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Background Extensive ablation in addition to pulmonary vein isolation (PVI) would be effective for modification of non-pulmonary vein (non-PV) substrates, whereas PVI might be sufficient for elimination of PV triggers. This study aimed to test the hypothesis that in patients with reproducible atrial fibrillation (AF) triggered by premature atrial contractions originating only from PVs, PVI alone can be sufficient to maintain sinus rhythm.Methods and Results:This study is a prespecified subanalysis of the EARNEST-PVI randomized controlled trial. This study investigated the efficacy of the PVI-alone strategy (PVI-alone) in comparison with the extensive strategy (PVI-plus) for persistent AF with a trigger-based mechanism vs. a substrate-based mechanism. Patients were stratified into 3 groups based on AF mechanisms: (1) Substrate group (N=236); (2) PV trigger group (N=236); and (3) non-PV trigger group (N=24). The hazard ratios for AF recurrence of the PVI-alone strategy with reference to the PVI-plus strategy were 1.456 (95% confidence interval [CI] [0.864-2.452]) in the substrate group, 1.648 (95% CI 0.969-2.801) in the PV trigger group, and 0.937 (95% CI 0.252-3.488) in the non-PV trigger group. No significant interaction between ablation strategy and AF mechanism was observed (P for interaction=0.748). Conclusions This study indicated that the efficacies of the PVI-alone strategy compared with the PVI-plus strategy were consistent across persistent AF with trigger-based and substrate-based mechanisms.

BACKGROUND The optimum cut-off value of premature atrial contraction (PAC) burden (CV-PACb) in 24-h Holter electrocardiography (24-h ECG) for predicting atrial fibrillation (AF) is debatable, with few validation data.Methods and Results:We retrospectively analyzed 61 patients already diagnosed with AF (AD-AF) and 147 patients never diagnosed with AF (ND-AF), aged ≥50 years, free of heart disease, and who had undergone 24-h ECG and transthoracic echocardiography (TTE). Receiver operating characteristic analysis demonstrated that 0.4% was the optimal CV-PACb differentiating AD-AF from ND-AF, with 69% sensitivity and 72% specificity (area under the curve [AUC] 0.72; 95% confidence interval [CI] 0.65-0.79); however, the left atrial volume index was not significant (AUC 0.60; 95% CI 0.51-0.68). To verify the CV-PACb, new propensity-matched cohorts (i.e., subjects with a PAC burden ≥0.4% and

BackgroundThyrotoxic atrial fibrillation (TAF) is a recognized significant complication of hyperthyroidism. Early identification of the individuals predisposed to TAF would improve thyrotoxic patients’ management. However, to our knowledge, an instrument that establishes an individual risk of the condition is unavailable. Therefore, the aim of this study is to build a TAF prediction model and rank TAF predictors in order of importance using machine learning techniques.MethodsIn this retrospective study, we have investigated 36 demographic and clinical features for 420 patients with overt hyperthyroidism, 30% of which had TAF. At first, the association of these features with TAF was evaluated by classical statistical methods. Then, we developed several TAF prediction models with eight different machine learning classifiers and compared them by performance metrics. The models included ten features that were selected based on their clinical effectuality and importance for model output. Finally, we ranked TAF predictors, elicited from the optimal final model, by the machine learning tehniques.ResultsThe best performance metrics prediction model was built with the extreme gradient boosting classifier. It had the reasonable accuracy of 84% and AUROC of 0.89 on the test set. The model confirmed such well-known TAF risk factors as age, sex, hyperthyroidism duration, heart rate and some concomitant cardiovascular diseases (arterial hypertension and conjestive heart rate). We also identified premature atrial contraction and premature ventricular contraction as new TAF predictors. The top five TAF predictors, elicited from the model, included (in order of importance) PAC, PVC, hyperthyroidism duration, heart rate during hyperthyroidism and age.ConclusionsWe developed a machine learning model for TAF prediction. It seems to be the first available analytical tool for TAF risk assessment. In addition, we defined five most important TAF predictors, including premature atrial contraction and premature ventricular contraction as the new ones. These results have contributed to TAF prediction investigation and may serve as a basis for further research focused on TAF prediction improvement and facilitation of thyrotoxic patients’ management.

Background Electrocardiogram (ECG) is a widely accessible diagnostic tool that can easily be obtained on admission and can reduce excessive contact with coronavirus disease 2019 (COVID‐19) patients. A systematic review and meta‐analysis were performed to evaluate the latest evidence on the association of ECG on admission and the poor outcomes in COVID‐19. Methods A literature search was conducted on online databases for observational studies evaluating ECG parameters and composite poor outcomes comprising ICU admission, severe illness, and mortality in COVID‐19 patients. Results A total of 2,539 patients from seven studies were included in this analysis. Pooled analysis showed that a longer corrected QT (QTc) interval and more frequent prolonged QTc interval were associated with composite poor outcome ([WMD 6.04 [2.62‐9.45], P = .001; I 2:0%] and [RR 1.89 [1.52‐2.36], P, Electrocardiography abnormalities on admission, including longer QTc interval and prolonged QTc interval, longer QRS duration, a faster heart rate, the presence of LBBB, PAC, PVC, T‐wave inversion, and ST‐depression are significantly associated with an increased composite poor outcome in patients with COVID‐19.

Background Atrial fibrillation (AF) is the world’s most common heart rhythm disorder and even several minutes of AF episodes can contribute to risk for complications, including stroke. However, AF often goes undiagnosed owing to the fact that it can be paroxysmal, brief, and asymptomatic. Objective To facilitate better AF monitoring, we studied the feasibility of AF detection using a continuous electrocardiogram (ECG) signal recorded from a novel wearable armband device. Methods In our 2-step algorithm, we first calculate the R-R interval variability–based features to capture randomness that can indicate a segment of data possibly containing AF, and subsequently discriminate normal sinus rhythm from the possible AF episodes. Next, we use density Poincaré plot-derived image domain features along with a support vector machine to separate premature atrial/ventricular contraction episodes from any AF episodes. We trained and validated our model using the ECG data obtained from a subset of the MIMIC-III (Medical Information Mart for Intensive Care III) database containing 30 subjects. Results When we tested our model using the novel wearable armband ECG dataset containing 12 subjects, the proposed method achieved sensitivity, specificity, accuracy, and F1 score of 99.89%, 99.99%, 99.98%, and 0.9989, respectively. Moreover, when compared with several existing methods with the armband data, our proposed method outperformed the others, which shows its efficacy. Conclusion Our study suggests that the novel wearable armband device and our algorithm can be used as a potential tool for continuous AF monitoring with high accuracy.

Background Premature atrial contractions (PACs) are associated with increased risk of atrial fibrillation (AF) and ischemic stroke. Although lifestyle and risk factor modification reduces AF incidence, their relationship to PACs frequency is unclear. We assessed the association of Life's Simple 7 (LS7) and individual LS7 factors in midlife with PACs frequency in late life in the Atherosclerosis Risk in Communities (ARIC) Study. Methods We followed 1924 participants from ARIC clinic Visit 3 (1993‐–95) to Visit 6 (2016–17) when a 2-week continuous heart rhythm monitor (Zio®XT Patch) was applied. LS7 factors were assessed at Visit 3 and a composite score was calculated. PACs frequency was categorized as minimal ( ≥ 0.1%–5%) and frequent (>5%). Logistic regression was used to evaluate the association of LS7 score and individual factors with PACs frequency. Results Each 1-point LS7 score increase was associated with lower odds of frequent PACs vs. no PACs (OR [95% CI]: 0.87 [0.78, 0.98]) and frequent PACs vs. occasional PACs (OR [95% CI]: 0.88 [0.79, 0.98]). Of the individual LS7 factors, compared with ideal physical activity, poor physical activity was associated with 81% higher odds of frequent PACs vs. no PACs. Compared with ideal BMI, poor BMI was associated with 41% higher odds of occasional PACs vs. no PACs. Conclusion Lifestyle risk factors, particularly physical activity and BMI, are associated with higher odds of PACs frequency. More research is needed to determine whether modifying these risk factors in midlife would prevent frequent PACs, and thereby prevent AF and stroke in older age.

To evaluate the association of premature atrial contraction (PAC) frequency with cognitive test scores and prevalence of dementia or mild cognitive impairment (MCI).We conducted a cross-sectional analysis using Atherosclerosis Risk in Communities study visit 6 (January 1, 2016, through December 31, 2017) data. We included 2163 participants without atrial fibrillation (AF) (age mean ± SD, 79±4 years; 1273 (58.9%) female; and 604 (27.97.0% Black) who underwent cognitive testing and wore a leadless, ambulatory electrocardiogram monitor for 14 days. We categorized PAC frequency based on the percent of beats: less than 1%, minimal; 1% to5%, occasional; greater than or equal to 5%, frequent. We derived cognitive domain-specific factor scores (memory, executive function, language, and global z-score). Dementia and MCI were adjudicated.During a mean analyzable time of 12.6±2.6 days, 339 (15.7%) had occasional PACs and 107 (4.9%) had frequent PACs. Individuals with frequent PACs (vs minimal) had lower executive function factor scores by 0.30 (95% CI, -0.46 to -0.14) and lower global factor scores by 0.20 (95% CI, -0.33 to -0.07) after multivariable adjustment. Individuals with frequent PACs (vs minimal) had higher odds of prevalent dementia or MCI after multivariable adjustment (odds ratio, 1.74; 95% CI, 1.09 to 2.79). These associations were unchanged with additional adjustment for stroke.In community-dwelling older adults without AF, frequent PACs were cross-sectionally associated with lower executive and global cognitive function and greater prevalence of dementia or MCI, independently of stroke. Our findings lend support to the notion that atrial cardiomyopathy may be a driver of AF-related outcomes. Further research to confirm these associations prospectively and to elucidate underlying mechanisms is warranted.

BACKGROUND: Binge drinking is a common atrial fibrillation (AF) trigger, however the mechanisms are poorly understood. OBJECTIVE: To investigate the effects of alcohol intoxication and hangover with rhythm monitoring and cardiac MRI. METHODS: Patients underwent serial cardiac MRI pre- and post-binge with continuous Holter monitoring. Time periods analyzed: baseline (24 h pre-binge), consumption, hangover (0- 24 h post-consumption) and post-hangover (24-48 h post-consumption). RESULTS: 50 patients (age 49 ± 15 years, 40% paroxysmal AF) completed the study (intake 8.4 ± 3.1 standard drinks). Mean heart rate increased from 72 ± 10 to 80 ± 13 beats per minute (bpm) during consumption (p

The number of confirmed COVID-19 cases has increased drastically; however, information regarding the impact of this disease on the occurrence of arrhythmias is scarce. The aim of this study was to determine the impact of COVID-19 on arrhythmia occurrence. This prospective study included patients with COVID-19 treated at the Leishenshan Temporary Hospital of Wuhan City, China, from February 24 to April 5, 2020. Demographic, comorbidity, and arrhythmias data were collected from patients with COVID-19 (n = 84) and compared with control data from patients with bacterial pneumonia (n = 84) infection. Furthermore, comparisons were made between patients with severe and nonsevere COVID-19 and between older and younger patients. Compared with patients with bacterial pneumonia, those with COVID-19 had higher total, mean, and minimum heart rates (all P < 0.01 ). Patients with severe COVID-19 (severe and critical type diseases) developed more atrial arrhythmias compared with those with nonsevere symptoms. Plasma creatine kinase isoenzyme (CKMB) levels ( P = 0.01 ) were higher in the severe group than in the nonsevere group, and there were more deaths in the severe group than in the nonsevere group (6 (15%) vs. 3 (2.30%); P = 0.05 ). Premature atrial contractions (PAC) and nonsustained atrial tachycardia (NSAT) were significantly positively correlated with plasma CKMB levels but not with high-sensitive cardiac troponin I or myoglobin levels. Our data demonstrate that COVID-19 patients have higher total, mean, and minimum heart rates compared with those with bacterial pneumonia. Patients with severe or critical disease had more frequent atrial arrhythmias (including PAC and AF) and higher CKMB levels and mortality than those with nonsevere symptoms.

Shengwei Wang,1 Hao Cui,2 Keshan Ji,3 Changsheng Zhu,4 Xiaohong Huang,3 Yongqiang Lai,1 Shuiyun Wang4 1Cardiovascular Surgery Center, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart, Lung and Blood Vascular Diseases, Beijing, People’s Republic of China; 2Department of Cardiovascular Surgery, Mayo Clinic, Rochester, MN, USA; 3Special Medical Treatment Center, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China; 4Department of Cardiovascular Surgery, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of ChinaCorrespondence: Yongqiang LaiCardiovascular Surgery Center, Beijing Anzhen Hospital, Capital Medical University, Beijing Institute of Heart, Lung and Blood Vascular Diseases, No. 2, Anzhen Road, Chaoyang District, Beijing, 100029, People’s Republic of ChinaEmail yongqianglai@yahoo.comShuiyun WangDepartment of Cardiovascular Surgery, State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 167, Beilishi Road, Xicheng District, Beijing, 100037, People’s Republic of ChinaEmail wsymd@sina.comPurpose: Obstructive sleep apnea (OSA) and myocardial fibrosis are associated with cardiac arrhythmia. The purpose of this study was to explore the relationship between OSA and myocardial fibrosis, as well as their impact on cardiac arrhythmia in hypertrophic obstructive cardiomyopathy (HOCM) patients.Methods: We prospectively studied 151 consecutive patients with a confirmed diagnosis of HOCM at the Fuwai Hospital between September 2017 and 2018. Polysomnography, Holter electrocardiography, and cardiac magnetic resonance imaging were performed on all patients. Myocardial fibrosis was reflected by late gadolinium enhancement (LGE), detected using cardiac magnetic resonance imaging.Results: Myocardial fibrosis, measured using LGE%, was found to increase with increasing OSA severity [6.8% (3.6– 12.9%), 6.1% (3.4– 10.0%), 9.6% (5.5– 14.5%), and 15.5% (9.3– 20.0%) for no-OSA, mild OSA, moderate OSA, and severe OSA, respectively; p=0.003]. LGE% correlated with the New York Heart Association functional classifications (p=0.018), septal thickness (p=0.026), and apnea-hypopnea index (AHI) (p< 0.001). The prevalence of isolated premature ventricular contraction (PVC) (p=0.028), paired PVC (p=0.036), ventricular bigeminy (p=0.005)/trigeminy (p< 0.001), non-sustained ventricular tachycardia (NSVT) (p=0.001), isolated premature atrial contraction (PAC) (p=0.032), and supraventricular tachycardia (p=0.029) was significantly higher in patients with OSA. Additionally, LGE% and AHI were independent risk factors for isolated PVC (OR: 1.04, p=0.001 and OR: 1.07, p=0.039, respectively), ventricular bigeminy (OR: 1.04, p=0.003 and OR: 1.26, p=0.002, respectively)/trigeminy (OR: 1.07, p=0.040 and OR: 1.06, p=0.001, respectively), and NSVT (OR: 1.17, p< 0.001 and OR: 1.08, p< 0.001, respectively) after adjustment for age, sex, and other parameters.Conclusion: Both OSA and LGE% were associated with a greater likelihood and increased frequency of ventricular arrhythmias (including NSVT) in patients with HOCM. Thus, the severity of OSA was independently associated with more severe myocardial fibrosis in patients with HOCM.Keywords: hypertrophic obstructive cardiomyopathy, obstructive sleep apnea, cardiac arrhythmia

Objective. Low-dose nonselective β blockade is an effective treatment for problematic infantile hemangioma (PIH). Screening electrocardiograms (ECG) are performed prior to the initiation of propranolol to minimize the risk of exacerbating undiagnosed heart block. How ECG results affect subsequent propranolol usage and patient management remains unclear. We examined the value of ECG prior to propranolol therapy in a quaternary pediatric hospital. Methods. A retrospective chart review was performed on all infants who received propranolol (2 mg/kg/day divided three times daily) to treat PIH at Arkansas Children’s Hospital from Sept. 2008 to Sept. 2015. All available demographic, historical, and clinical data were obtained. ECGs and echocardiographic data were reviewed and summarized. A pediatric cardiologist read all ECGs. Results. A total of 333 patients (75% female) received propranolol therapy. ECG information was available for 317 (95%). Abnormal findings were present on 44/317 (13.9%) of study ECGs. The most common abnormal finding was “voltage criteria for ventricular hypertrophy” ( n = 35 , 76.1%). Two patients had abnormal rhythms; one had first-degree atrioventricular (AV) block, and one had occasional premature atrial contractions. Of the 31 patients who underwent echocardiograms, 20 (35%) were abnormal. 2.9% of infants with PIH treated with propranolol required a follow-up with a cardiologist. No patient was precluded from taking propranolol due to the findings on screening ECG. Conclusions. Screening ECGs prior to propranolol therapy are abnormal in nearly 14% of patients with PIH but are unlikely to preclude therapy. In the absence of prior cardiac history, this cohort offers further evidence suggesting that screening ECGs may be of limited value in determining the safety of propranolol in otherwise healthy infants with PIH.

Premature atrial complexes (PACs) are a common finding in patients with structural heart disease, as well as in healthy subjects. In addition to the clinical spectrum ranging from asymptomatic patients to irritating palpitations, PACs are suggested to be associated with an increased risk of atrial fibrillation and stroke. Medical treatment leads to a significant reduction in PACs with clear symptom relief in a large proportion of patients, but is limited in cases of PACs that are refractory to antiarrhythmic drug (AAD) treatment. Furthermore, proarrhythmic effects of AAD or the patient’s refusal of AAD treatment due to side effects need to be considered. Ablation of PACs is a good alternative to medical therapy with a comparable safety profile and at least comparable efficacy. In recent years, ultra-high-density (UHD) mapping with multiple improvements for successful ablation has been evolving. Before the introduction of UHD mapping, ablation strategies included activation mapping with single-tip catheters or conventional mapping aiming for the earliest activation of the PAC locally, with the earliest activation suspected to be the origin of the PAC and targeted by radiofrequency (RF) ablation. Using UHD mapping, a three-dimensional local activation map of the atrium can be acquired, identifying the point of earliest activation within the high-resolution map. PAC ablation has therefore developed into a true alternative for the treatment of symptomatic PACs.

Background Tachycardia and heart rate irregularity are proposed triggers of premature ventricular contraction–induced cardiomyopathy (PVC-cardiomyopathy). Bigeminal premature atrial and ventricular contractions (PACs and PVCs) increase heart rate and result in rhythm irregularities but differ in their effects on ventricular synchrony. Comparing chronic bigeminal PACs with PVCs would provide insights into mechanisms of PVC-cardiomyopathy. Objective To compare the impact of chronic PACs and PVCs on ventricular hemodynamics, structure, and function. Methods Pacemakers were implanted in 27 canines to reproduce atrial (PACs, n = 7) or ventricular bigeminy (PVCs, n = 11) for 12 weeks, and compared to sham-operated animals (n = 9). Four additional animals were exposed to long-term bigeminal PVCs (48 weeks). Hemodynamic changes were assessed using a pressure-transducing catheter at baseline and 12 weeks. Cardiac remodeling was monitored by transthoracic echocardiography throughout the 12- and 48-week protocols in the respective groups. Results PVC group demonstrated a significant decrease in left ventricular (LV) ejection fraction and contractility (max dP/dt), impaired LV lusitropy (min dP/dt), and increase in LV dimensions and LV mass at 12 weeks without further deterioration beyond 16 weeks. Despite increased LV mass, relative wall thickness decreased, consistent with eccentric hypertrophy. No significant cardiac remodeling was noted in either sham or PAC groups at 12 weeks. Conclusion In contrast to bigeminal PACs, PVCs result in a cardiomyopathy characterized by reduced LV ejection fraction, LV dilation, and eccentric hypertrophy that plateaus between 12 and 16 weeks. The lack of remodeling in chronic PACs suggests that tachycardia and heart rate irregularity do not play a significant role on the development of PVC-cardiomyopathy., Graphical abstract

Background Atrial fibrillation (AF) is the most common sustained arrhythmia, with growing evidence identifying obesity as an important risk factor for the development of AF. Although defective atrial myocyte excitability due to stress-induced remodeling of ion channels is commonly observed in the setting of AF, little is known about the mechanistic link between obesity and AF. Recent studies have identified increased cardiac late sodium current (INa,L) downstream of calmodulin-dependent kinase II (CaMKII) activation as an important driver of AF susceptibility. Methods Here, we investigated a possible role for CaMKII-dependent INa,L in obesity-induced AF using wild-type (WT) and whole-body knock-in mice that ablates phosphorylation of the Nav1.5 sodium channel and prevents augmentation of the late sodium current (S571A; SA mice). Results A high-fat diet (HFD) increased susceptibility to arrhythmias in WT mice, while SA mice were protected from this effect. Unexpectedly, SA mice had improved glucose homeostasis and decreased body weight compared to WT mice. However, SA mice also had reduced food consumption compared to WT mice. Controlling for food consumption through pair feeding of WT and SA mice abrogated differences in weight gain and AF inducibility, but not atrial fibrosis, premature atrial contractions or metabolic capacity. Conclusions These data demonstrate a novel role for CaMKII-dependent regulation of Nav1.5 in mediating susceptibility to arrhythmias and whole-body metabolism under conditions of diet-induced obesity.

Newborn male with symptomatic bradycardia initially diagnosed with complete atrioventricular block. Isoproterenol drip was initiated, and the patient was scheduled for pacemaker implantation. During the hospital course, repeat electrocardiogram and Holter monitor revealed evidence of near continuous blocked atrial bigeminy with occasional aberrantly conducted premature atrial contractions. Flecainide was started, resulting in normal sinus rhythm, and the pacemaker implantation was cancelled.

Background The role of nonpulmonary vein (PV) triggers ablation in persistent atrial fibrillation (PEAF) was suggested but it is still under debate. Objectives We aimed to assess the effectiveness of non-PV trigger-targeted ablation for patients with PEAF. Methods Consecutive patients with PEAF undergoing catheter ablation (CA) between January 2015 and April 2017 were enrolled. Isoproterenol plus adenosine challenge was performed to provoke non-PV triggers. Non-PV triggers were defined as the trigger beats inducing AF (non-PV AF triggers) and/or frequent premature contractions (non-PV PACs) from other than PVs. Three groups were defined: Group 1 (n = 186) without non-PV triggers; Group 2 (n = 65) with non-PV triggers that could be completely eliminated with CA; Group 3 (n = 49) with non-PV triggers still inducible after CA. The primary endpoint was freedom from any atrial tachyarrhythmia (ATa) recurrence. Results A total of 300 patients (230 males, age 64 ± 10) were enrolled. The mean follow-up period was 27 ± 10 months. Freedom from ATa recurrence at 1 and 2 years were significantly lower in Group 3 compared to the other two groups (Group 1; 74.7%, 67.2% vs. Group 2; 75.8%, 68.3% vs. Group 3: 52.1%, 38.6%, p = .0005), irrespective of the type of non-PV triggers (non-PV AF triggers vs. non-PV PACs). On multivariate analysis, unsuccessful elimination of non-PV triggers was an independent predictor for ATa recurrence (hazard ratio = 1.80, 95% confidence interval = 1.07-2.95, p = .026). Conclusion Successful non-PV triggers elimination can improve the ATa recurrence rate in PEAF ablation. ATa recurrence rate is higher, if non-PV AF triggers or even non-PV PACs remain in patients with PEAF.

Aim The purpose of this study was to establish a simple method to distinguish premature ventricular contractions (PVC) from premature atrial contractions (PAC) using a fetal Doppler ultrasound arterial pulse waveform to measure time intervals between sinus node restarting. Methods We retrospectively identified 14 fetuses with premature contraction (8 with PAC, 6 with PVC). We measured two distinct parts of time intervals using an arterial pulsed‐wave Doppler: the two consecutive waveforms just before the premature contraction (2‐V interval) and two consecutive waveforms including the premature contraction (XV interval) to measure time intervals between sinus node restarting. We then evaluated the time difference between the 2‐V and XV intervals in PVC compared to PAC. Results For PVC, the difference between the 2‐V interval and the XV interval was significantly shorter than that for PAC. A cut‐off point of 33 ms, where a difference ≤33 ms was clearly shown to be associated with a PVC and a difference more than 33 ms signified a PAC was demonstrated. Conclusion The 2‐V and XV interval measurements, used to measure time intervals between sinus node restarting, could easily distinguish PVC from PAC in utero. Therefore, this study could potentially be a feasible and effective method for obstetricians or sonographers to employ usefully.

The incidence of ventricular arrhythmia in patients with an implanted pacemaker is not yet known. The aim of this study was to analyze non-sustained ventricular tachycardia (NSVT) episodes based on stored electrograms (EGM) and determine the occurrence rate and risk factors for NSVT in a pacemaker population.This study included 302 consecutive patients with a dual-chamber pacemaker. A total of 1024 EGMs stored in pacemakers as ventricular high-rate episodes were analyzed. The definition of NSVT was ≥ 5 consecutive ventricular beats at ≥ 150 bpm lasting < 30 seconds.In baseline, most patients (94.8%) had ≥ 60% left ventricular ejection fraction. Of 1024 EGMs, 420 (41.0%) showed appropriate NSVT episodes, as well as premature atrial contractions, atrial tachyarrhythmia, or atrial fibrillation with a rapid ventricular response, whereas other EGMs did not show an actual ventricular arrhythmia. On EGM analysis, during a mean follow-up period of 46.1 months, NSVT occurred one or more times in 82 patients (33.1%). On multivariate analysis, ≥ 50% right ventricular pacing was an independent risk factor for NSVT (odds ratios, 4.519; P < 0.001), but NSVT was not associated with increased all-cause mortality.Moreover, in the pacemaker population, ≥ 50% right ventricular pacing is an independent risk factor for NSVT; however, NSVT was not associated with increased all-cause mortality because of the preserved left ventricular function.

AimsNo data exist concerning the clinical performances of the subcutaneous implantable cardioverter-defibrillator (S-ICD) atrial fibrillation (AF) detection algorithm. We aimed to study the performances and implications of the latter in a ‘real-world’ setting.Methods and resultsBetween July 2017 and August 2019, 155 consecutive S-ICD recipients were included. Endpoint of the study was the incidence of de novo or recurrent AF using a combined on-site and remote-monitoring follow-up approach. After a mean follow-up of 13 ± 8 months, 2531 AF alerts were generated for 55 patients. A blinded analysis of the 1950 subcutaneous electrocardiograms available was performed. Among them 47% were true AF, 23% were premature atrial contractions or non-sustained AF, 29% were premature ventricular contractions or non-sustained ventricular tachycardia, and 1% were misdetection. Fourteen percent (21/155) patients had at least one correct diagnosis of AF by the S-ICD algorithm. One patient presented symptomatic paroxysmal AF not diagnosed by the S-ICD algorithm (false negative patient). Patient-based sensitivity, specificity, positive, and negative predictive values were respectively 95%, 74%, 38%, and 99%. Among patients with at least one correct diagnosis of AF, 38% (8/21) had subsequent clinical implications (anticoagulation initiation or rhythm control therapies).ConclusionThe S-ICD AF detection algorithm yields a high sensitivity for AF diagnosis. Low specificity and positive predictive value contribute to a high remote monitoring-notification workload and underline the necessity of a manual analysis. Atrial fibrillation diagnosis by the S-ICD AF detection algorithm might lead to significant therapeutic adjustments.

Background Direct-acting antiviral agents (DAAs) cure patients with hepatitis C virus (HCV) infection. Concerns have arisen the occurrence of significant bradyarrhythmias during treatment with DAAs. The aim of this study was to assess the impact of a DAA combination for the treatment of HCV infection on heart rate, rhythm, and heart rate variability (HRV) using 24-h ECG monitoring. Results A prospective randomized study of 50 treatment-naïve patients with HCV infection treated with a combination of sofosbuvir 400 mg daily and daclatasvir 60 mg daily for 12 weeks. Surface ECG and 24-h ECG monitoring were performed at baseline and after completion of therapy to assess PR interval, corrected QT interval (QTc), minimum heart rate (HR), maximum HR, average HR, HRV time-domain and frequency-domain measures, significant pauses, tachycardias, bradycardias, premature atrial contractions (PACs), and premature ventricular contraction (PVCs). No differences were detected in all examined parameters between baseline and after completion of treatment. PR interval was 154 ± 25.95 vs 151.4 ± 23.82 ms, respectively (p = 0.124). QTc interval was 397.34 ± 29.38 vs 395.04 ± 30.23 ms, respectively (p = 0.403). No differences were detected for minimum HR, maximum HR, average HR, HRV time-domain and frequency-domain measures, the occurrence of significant pauses, sinus tachycardia episodes, sinus bradycardia episodes, PACs, and PVCs. No episodes of bradyarrhythmias, syncope, and atrial fibrillation, supraventricular, or ventricular tachycardias were reported or detected. Conclusion In non-cardiac patients receiving no cardioactive medications, the combination of sofosbuvir and daclatasvir for the treatment of HCV infection has no effect on HR, rhythm, conductivity, or HRV. No symptomatic bradycardias, tachycardias, or syncope were reported or detected using 24-h ECG monitoring.

Purpose Chronic obstructive pulmonary disease (COPD) is associated with increased incidence of arrhythmias, which has been attributed to autonomic dysregulation. Detection of autonomic function may facilitate stratification of COPD patients with respect to their risk of development of arrhythmias. Patients and methods A total of 151 COPD patients and 45 non-COPD patients were included in this study. Heart rate deceleration runs (DRs) were detected by dynamic electrocardiogram (ECG); DRs successively occurring in 2, 4, or 8 cardiac cycles were denoted as DR2, DR4, and DR8, respectively. Indicators of arrhythmias including isolated premature atrial contractions (PAC), supraventricular tachycardia (SVT), isolated premature ventricular contractions (PVC), and ventricular tachycardia (VT) were recorded. Occurrence of SVT or PAC ≥70/day was considered positive for supraventricular arrhythmias, while positive ventricular arrhythmias category (PVAC) was defined as occurrence of VT or PVC ≥10/hour. Results Compared with non-COPD individuals, COPD patients were associated with increased number of PAC, PVC, higher incidence of PAC >70/d, SVT, PVAC, and decreased DRs (DR2, DR4, DR8) (P 70/d, SVT, and PVAC. The predictive power of DRs was significantly different from one another with the order ranged as DR4>DR8>DR2 for PAC >70/d, DR8>DR4>DR2 for SVT, and DR8>DR4>DR2 for PVAC. Conclusion Our study provides evidence of significant autonomic dysregulation in COPD patients. DRs may serve as a marker of the risk of arrhythmias in COPD patients.

Introduction. Determination of ventricular and supraventricular arrhythmias with left bundle branch block morphology (LBBB) seems to be one of the most complex diagnostic tasks when P waves are not clearly identifiable on 12-lead ECG. Previously described criteria for differential diagnosis of wide QRS arrhythmias had low accuracy especially for patients from various clinical groups and also those taking antiarrhythmic drugs. When patient’s clinical data, medical history or physical examination results are not available the number of misdiagnosis may increase leading to improper treatment. Therefore, development of new temporal and amplitude based characteristics of wide QRS complex arrhythmias with LBBB morphology in patients of any clinical groups is an important task.Methods. Twenty-eight consecutive patients with wide QRS premature beats and LBBB morphology identified by 24-hour and long-term ECG monitoring (ZAO “INCART”, Russia) were enrolled in the study. Fourteen patients had premature atrial contractions (PAC) and fourteen patients had premature ventricular contractions (PVC) during sinus rhythm. For each patient 10 typical single wide QRS complexes in 12 ECG leads were analyzed. The duration of QRS complexes, time intrinsic deflection (TID) and electrical axis of the heart were determined automatically in 12 leads ECG using KT Result 3 software (ZAO “INCART”, Russia). The experts assessed morphology of the QRS complexes and transition zone location in leads V1-V6. ROC analysis with optimal cut-off value level evaluation as well as calculation of sensitivity (SV), specificity (SP) and diagnostic accuracy (ACC) were performed for qualitative and quantitative assessment of diagnostic value of PAC and PVC amplitude and temporal characteristics. Comparison of diagnostic values of wide QRS complex morphological and temporal criteria was performed based on the AUC difference and the corresponding p-value assessment.Results. The results of study found out that V5, V1 leads were more informative for assessment of QRS complex morphology and duration while V1 and V4 leads were more informative for TID calculation in differential diagnosis of wide QRS complexes arrhythmias with LBBB morphology. PAC with aberrant conduction had the following characteristics: TID < 68 ms in V1 lead and TID < 62 ms in V4 lead; QRS < 136 ms; transition zone in the leads V5, V6; QS, rS or RS complexes (with S> R) with low-amplitude r/R waves in leads V1-V4; electric axis of the heart less than 80° in standard leads. In all cases PVCs were characterized by QRS > 160 ms and TID > 88 ms in V1-V6 leads.Conclusions. New various criteria which can improve differential diagnosis of wide QRS complexes with LBBB morphology were identified in this study. These criteria should be tested in a larger group of patients with various forms of wide QRS complex arrhythmias and different PVC localizations including information of structural heart diseases due to the small sample size in this study.Conflicts of Interest: Viktor M. Tikhonenko - CEO (Director General) of the Institute of Cardiology Technics (INCART), Saint-Petersburg, Russia.

Background: Arrhythmias are common cardiovascular complications in multiple myeloma (MM) patients and are related to a poor prognosis.Objective: This study aimed to assess the burden of arrhythmias and their prognostic value in patients with MM.Methods: This was a retrospective study of patients with MM between January 2015 and April 2020 at the First Affiliated Hospital of Xi'an Jiaotong University. The incidence of arrhythmia and associated risk factors were evaluated. The relationship between the type of arrhythmia and survival was analyzed.Results: A total of 319 patients with MM were identified, and 48.0% (153/319) had arrhythmias. The most common type of arrhythmia was sinus tachycardia (ST) (15.0%, 48/319), followed by sinus bradycardia (SB) (14.4%, 46/319), premature atrial contractions (PACs) (6.3%, 20/319), conduction disorders (CDs) (6.0%, 19/319), atrial fibrillation (AF) (6.0%, 19/319), premature ventricular contractions (PVCs) (4.4%, 14/319) and paroxysmal supraventricular tachycardia (PSVT) (0.6%, 2/319). The patients with arrhythmias had higher levels of log NT-proBNP and creatinine, greater bortezomib use, and a higher incidence of diabetes than those without arrhythmias (P < 0.05). The all-cause mortality rates of patients without arrhythmias and those with AF, ST, PACs, CDs, SB, and PVCs were 50.6% (84/166), 73.7% (14/19), 60.4% (29/48), 60.0% (12/20), 52.6% (10/19), 34.8% (16/46), and 28.6% (4/14), respectively. In a subgroup analysis of patients experiencing different types of arrhythmias, patients with SB had lower all-cause mortality than patients with AF (P < 0.01). Univariate and multivariate Cox analyses showed that there was a positive statistically significant association between SB and survival (HR: 0.592 [0.352–0.998], P = 0.049) in a subgroup analysis of different arrhythmias.Conclusions: Patients with MM had a heavy arrhythmia burden, and in this study, approximately half of MM patients had arrhythmias. MM patients with SB were associated with lower all-cause mortality than those with AF. SB might be an independent positive factor for prognosis.

Background Frequent premature atrial contractions (PACs) are associated with substantially increased risk of atrial fibrillation (AF) and stroke, but PAC count varies substantially day-to-day. With the emergence of potential therapies for primary prevention of AF reliable estimation of PAC frequency is increasingly relevant, as is an understanding of PAC determinants. Purpose To determine the effect of daily activity and heart rate on an individuals' daily PAC count. Methods We included a random sample of patients 18–85 years without AF who recorded an ambulatory ECG for 7–31 days in the U.S.A during 2019 using a full-disclosure mobile cardiac telemetry device, and who had ≥500PACs on at least one recording day. PACs were algorithmically detected and manually verified. PAC count and activity was sampled for each individual and each recording day during daytime (06–22h). The effect of activity on daily PAC count was assessed in a negative binomial regression model including age, sex and with a random effect for individual, to account for confounding due to inter-individual differences. Results The study population consisted of 2,094 patients, of which 48% were men (Fig 1). Mean time spent in activity was 32% (standard deviation (SD 10%) for men and women 31% (SD 10%) for women (Fig 2). The median PAC count was 592 (inter-quartile range 1280). Beyond age, sex and intra-individual differences PAC frequency was determined by activity levels, (intercept 629 PACs; incidence rate ratio per 10 minute increase in activity 1.03, p Conclusions Physical activity is associated with increased PACs counts, implying both that a reliable diagnosis of PAC frequency needs to be conducted during a person's habitual level of activity and that PAC frequency is modifiable. In-hospital assessments of PACs while patients are mainly inactive may underestimate PAC frequency. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): the Swedish Society For Medical Researchthe Swedish Heart and Lung Foundation Age and sex distributionActivity levels by sex

Background Premature atrial contractions (PACs) are known predictor of atrial fibrillation; however very little has been revealed on its factors among Asian general population. We assessed the frequency of higher PAC counts and its association with relevant factors in general Japanese men. Methods We have conducted a population based cross sectional study among 517 healthy men from Kusatsu, Japan, aged between 40 and 79 years. 24 hours Holter electrocardiogram was performed to assess the PAC frequency. We divided participants into quartiles based on number of PACs/hour to compare the characteristics by using Cochran–Mantel–Hanzal test and ANOVA. We defined the highest quartile as event and multivariable logistic regression was performed to assess the significance with relevant factors. Results Median number of PACs was 2.84 PACs/hour. The highest quartile of PAC counts was >7.86PACs/hour. Age, triglycerides, blood pressure, ventricular contractions and heart rates were different among quartiles. In multivariable logistic regression analysis, higher age (OR, 95% CI: 1.35, 1.01-1.67), lower mean heart rates (OR, 95% CI: 0.97, 0.94-0.99), higher heart rate difference in a day (OR, 95% CI: 1.40, 1.12-1.75) and lower triglyceride (OR, 95% CI: 0.53, 0.33-0.82) were independently, significantly associated with highest quartile of PACs. Conclusions Higher PACs evaluated by Holter ECG was associated with higher age, lower heart rate, higher heart rate difference, and lower triglyceride in general Japanese men. Key messages The PAC frequency was high. Age, mean heart rates, difference between maximum and resting heart rates, triglycerides are possible risk factors for frequent PAC counts.

We evaluated the association of longitudinal changes in circulating levels of N-terminal pro B-type natriuretic peptide (NT-proBNP) and high sensitivity cardiac troponin T (hs-cTnT) with the burden of arrhythmias as captured by 2-week ambulatory ECG monitoring. This study included 1,930 Atherosclerosis Risk in Communities Study participants who wore a leadless, ambulatory ECG monitor (Zio XT Patch) at visit 6 (2016 to 2017) and had cardiac biomarkers measured at visit 6 and visit 4 (median of 19 years earlier). The mean age of participants at V6 was 79 ± 5 years, 41% were men, and 22% were black. Adjusting for demographics, body mass index, smoking, diabetes, hypertension, stroke, left ventricular mass, cardiac medications, patch wear time, visit 4 levels of NT-proBNP and hs-cTnT, and relative change in hs-cTnT, each log-transformed unit relative increase in NT-proBNP was associated with a higher likelihood of nonsustained ventricular tachycardia (odds ratio 1.29, 95% confidence interval [CI] 1.12 to 1.48), a higher number of daily atrial tachycardia episodes (geometric mean ratio [GMR] 1.16, 95% CI 1.10 to 1.21), and a higher daily ectopic burden (premature ventricular contractions -GMR 1.42, 95% CI 1.25 to 1.62; premature atrial contractions -GMR 1.40, 95% CI 1.25 to 1.57). In fully adjusted analyses, each log-transformed unit relative increase in hs-cTnT was only found to be weakly associated with a higher daily premature ventricular contraction burden (GMR 1.31, 95% CI 1.01 to 1.70). In conclusion, longitudinal change in NT-proBNP was associated with an increased atrial and ventricular arrhythmia burden.

Background: Excessive supraventricular ectopic activity (ESVEA), defined as ≥720 premature atrial contractions (PAC) per day or any runs of ≥20 PACs, has been proposed as a surrogate marker for paroxysmal atrial fibrillation (PAF). Objective: We aimed to estimate the prognostic impact of ESVEA on the future development of PAF in consecutive patients referred to ambulatory cardiac monitoring. Methods: The cohort consists of a population with comorbidities referred to 48-hour ambulatory electrocardiogram aged 30–98 (n = 1316) between 2009 and 2011. After exclusion of known or current atrial fibrillation (AF) (n = 527) and patients with pacemakers (n = 7), 782 patients were included, with a median follow-up of 8.1 years. Events of incident AF and death were retrieved from patient records. Results: Mean age was 58.6 ± 15.5 years and 56.5% were women. A total of 101 patients had ESVEA at baseline (12.9%). During follow-up, 69 (8.9%) developed incidental AF. Twenty-three patients with ESVEA developed AF (23%). Incidence rate of AF in patients with and without ESVEA was 37.1/1000 person-years and 9.1 per 1000 person-years, respectively (P < .001). ESVEA was associated with incident AF after adjustment for potential confounders in Cox regression analysis (hazard ratio [HR]: 2.39; 95% confidence interval [CI]: 1.40–4.09) and in competing risk analysis with death as competing risk (subdistribution HR: 2.35; 95% CI: 1.30–4.17). Conclusion: ESVEA increases the risk of incident AF substantially in a population referred to ambulatory cardiac monitoring.

Background Dysrhythmia and sudden cardiac arrest occur more likely in HIV patients than healthy subjects. Thus, we need to examine dysrhythmias adverse effects of medications including Efavirenz as early as possible especially in young subjects. Hypothesis Efavirenz might have contributed to increased risk of developing common types of dysrhythmia in young HIV infected patients. Methods We performed a retrospective cohort study among 62 patients on Efavirenz and 38 controls. All participants were under 40 years old without cardiovascular disease. Total significant dysrhythmia in 24‐hour ECG monitoring was the primary endpoint determined as the composite of high premature ventricular contraction (PVC) (>500 beats per 24 hours), high premature atrial contraction (PAC) (>500 bp24h), sinus pause, atrioventricular blocks, ventricular tachycardia, prolonged QTc, and low heart rate variability (HRV). Modified composite dysrhythmia consisted of low HRV (SD of normal‐to‐normal [SDNN]), high PVC and prolonged QT. Results Mean heart rate, Efavirenz regimen, male gender, and CD4 count predicted total dysrhythmia. Odds ratios were 1.108, 2.90, 4.36, and 0.96, respectively. The incidence of total dysrhythmia, high PVC, high PAC, low HRV(SDNN), and prolonged QTc were 54.8%, 41.85%, 9.71%, 45.2%, and 12.9% in patients on Efavirenz against 42.11%, 31.64%, 0%, 34.2%, and 7.91% in controls, respectively (p‐values: .031, .001

This is a case of a 63‐year‐old female presenting with diabetes mellitus, hypertension, hypothyroidism, and postmenopausal osteoporosis with findings showing abnormal AFT with reduced heart rate variability (HRV) and multiple lobed Poincaré plot, pointing to premature atrial contractions.

Infective endocarditis (IE) is a focus of infection which effects the endocardium, specifically the heart valves or intra-cardiac devices. A 64-year-old male with gastric carcinoma and no prior cardiac history presented to the emergency room with altered mental status. Initial investigations showed the patient had a leukocytosis with a left shift. Blood cultures taken upon arrival eventually grew Esherichia coli, thought to be from the urinary tract, although initial urinalysis was delayed until after initiation of antibiotics. Electrocardiogram showed sinus bradycardia with frequent premature atrial contractions. Chest X-Ray showed bilateral pleural effusions, which were eventually drained and found to be growing E. coli. Transthoracic echocardiogram was done which showed moderate-sized tricuspid valve vegetation with severe tricuspid regurgitation. IE has been increasing in incidence throughout the years. In prior decades IE was a disease primarily affecting patients with known rheumatic heart disease, prosthetic heart valves, and intravenous drug abusers however more commonly it is becoming healthcare acquired. E. coli is not often seen to be a culprit of IE. We present a rare case of E. coli endocarditis of a native tricuspid valve.

Пізні потенціали передсердь (ППП) і шлуночків (ППШ) – неінвазивні електрокардіографічні критерії наявності високої аритмічної готовності та ризику появи небезпечних для життя аритмій. Електричні властивості міокарда у хворих на гіпертонічну хворобу II стадії, що поєднана з субклінічним гіпотиреозом, раніше не вивчали.Мета роботи – дослідити зміни електричних властивостей міокарда передсердь і шлуночків у хворих на артеріальну гіпертензію, що поєднана з субклінічним гіпотиреозом (СГ).Матеріали та методи. Після підписання інформованої згоди у дослідження залучили 122 особи, які хворі на гіпертонічну хворобу (ГХ) ІІ стадії, та 16 практично здорових осіб. Критерії залучення в дослідження: наявність АГ II стадії без тиропатій і поєднаної з СГ (для хворих основної групи). Залежно від рівня тиреотропного гормона (ТТГ) пацієнтів із ГХ поділили на 2 групи: з нормальним (0,4–4,0 мкОД/мл) і помірно підвищеним рівнем ТТГ (4,0–15,6 мкОД/мл, за умови нормального рівня тиреоїдних гормонів). У групи хворих на гіпертонічну хворобу без СГ увійшли 92 пацієнти (75 жінок – 81,52 %, 17 чоловіків – 18,48 % ), у групи хворих на ГХ із супутнім СГ залучили 30 пацієнтів (26 жінок – 86,7 %, 4 чоловіки – 13,3 %). Усім хворим виконали добове моніторування АТ та ЕКГ (комбінований монітор ЕКГ та АТ «Кардіотехніка-04-АД-3», Санкт-Петербург, РФ). Використовували фільтр зі зрізом 40 Гц, запис – в ортогональних відведеннях X, Y, Z за Сімпсоном. Опрацювання даних здійснили за допомогою програми Statistica 6.0. Дані наведено як медіана і міжквартильний розмах Ме (25 %; 75 %).Результати. У хворих на ГХ без супутнього субклінічного гіпотиреозу (на відміну від практично здорових осіб) визначили переважання пізніх передсердних потенціалів (63 % проти 84 %; р = 0,0419) зі зростанням в 16,4 раза (р = 0,018) кількості надшлуночкових екстрасистол. Також у хворих на ГХ без супутнього субклінічного гіпотиреозу пізні потенціали шлуночків (ППШ) виявляли в 5,7 раза частіше (6 % проти 34 %, р = 0,0302), вони асоціюються з вірогідним (р = 0,004) збільшенням кількості шлуночкових екстрасистол за добу.У хворих на ГХ із супутнім субклінічним гіпотиреозом, на відміну від практично здорових осіб, переважала передсердна ектопічна активність (ППП виявили у 87 % проти 63 %, р = 0,0498), що супроводжувалось закономірним зростанням у 27,2 раза (р = 0,038) кількості надшлуночкових екстрасистол, та ектопічна активність шлуночків. Зміни електричних властивостей шлуночків супроводжувались збільшенням питомої ваги виявлених ППШ (77 % проти 6 %, р = 0,0001), котре асоціювалося з вірогідним (р = 0,001) збільшенням кількості шлуночкових екстрасистол за добу в цієї категорії хворих (441,53 ± 1414,97 проти 0,00 ± 0,00 у практично здорових осіб, р = 0,001).Хворі на ГХ із/без супутнього субклінічного гіпотиреозу не розрізнялися за показниками, що характеризують пізні потенціали передсердь. Не виявили також статистично вірогідної різниці показників кількості надшлуночкових екстрасистол (р = 0,527), парних надшлуночкових екстрасистол (р = 0,449), групових надшлуночкових екстрасистол (р = 0,314). Однак у хворих на ГХ із супутнім субклінічним гіпотиреозом спостерігали вірогідне зростання ектопічної активності шлуночків – ППШ виявили у 77 % проти 33 % в осіб без субклінічного гіпотиреозу (р = 0,0001), зміни електричних властивостей шлуночків у хворих на ГХ із супутнім субклінічним гіпотиреозом також асоціювалися зі зростанням кількості шлуночкових екстрасистол у 6,69 раза (з 42,56 ± 36,96 до 441,53 ± 1414,97, р = 0,026) порівняно з аналогічним показником у хворих на ГХ без супутнього субклінічного гіпотиреозу, що свідчить про негативний вплив субклінічного гіпотиреозу на електричні властивості шлуночків.Висновки. У хворих на АГ II стадії порівняно зі здоровими особами вірогідно змінені показники, що характеризують пізні потенціали передсердь і шлуночків, які супроводжуються збільшенням кількості надшлуночкових і шлуночкових порушень ритму. Субклінічний гіпотиреоз має додатковий проаритмічний вплив на міокард шлуночків при АГ., Late atrial and ventricular potentials are non-invasive electrocardiographic criteria for presence of high arrhythmic readiness and risk of life-threatening arrhythmias. The electrical properties of the myocardium in patients with stage II arterial hypertension (AH) combined with subclinical hypothyroidism have not been studied previously.Aim. To study the changes of electrical properties of the atrial and ventricular myocardium in patients with AH combined with subclinical hypothyroidism.Materials and methods. The criteria for inclusion in the study were the presence of stage II AH without thyroid gland pathology and combined with subclinical hypothyroidism (SH) (for patients of the main group). Depending on the level of thyroid-stimulating hormone (TSH), the AH patients were divided into 2 groups – with normal (0.4–4.0 mU/ml) and moderately elevated level of TSH (4.0–15.6 mU/l, with normal levels of thyroid hormones).The group of patients with AH without SH included 92 patients (women – 81.52 % (75), men – 18.48 % (17)); the group of patients with AH with concomitant SH included 30 patients (women – 86.7% (26), men – 13.3 % (4)). All patients underwent 24-h BP monitoring and ECG (combined ECG and BP monitor “Kardiotechnica-04-AD-3”,St. Petersburg,Russia). A 40 Hz cutoff filter was used recording in the X, Y, Z orthogonal leads. Data were processed with the help of a program Statistica 6.0. Data were presented as the median and inter-quartile range of Me (25 %; 75 %).Results. In AH patients without concomitant subclinical hypothyroidism, unlike in relatively healthy patients, late atrial potential predominance was seen (63 % vs. 84 %; P = 0.0419) with a 16.4 times (P = 0.018) increase in the number of premature atrial contractions. Also, in patients with AH without concomitant subclinical hypothyroidism late ventricular potentials (LVPs) occurred 5.7 times more often (6 % vs. 34 %, P = 0.0302) and were associated with a significant (P = 0.004) increase in the number of premature ventricular contractions per day in this category of patients.In SH patients with a concomitant subclinical hypothyroidism, unlike in relatively healthy individuals, atrial ectopic activity was significantly more predominant (LAP was found in 87 %; versus 63 %, P = 0.0498), which was accompanied by a logical 27.2 times (P = 0.038) increase in the number of premature atrial contractions and ventricular ectopic activity. Changes in the electrical properties of the ventricles were accompanied by an increase in the percentage of detected LVPs (77 % versus 6 %, P = 0.0001), which was associated with a significant (P = 0.001) increase in the number of premature ventricular contractions per day in this category of patients (441.53 ± 1414.97 versus 0.00 ±0.00 inalmost healthy subjects, P = 0.001).AH patients with and without concomitant SH did not differ from each other in terms of indexes characterizing late atrial potentials. There was also no statistically significant difference in the number of premature atrial contractions (P = 0.527), paired premature atrial contractions (P = 0.449), salvos of atrial premature contractions (P = 0.314). However, in AH patients with concomitant SH there was a significant increase in the ectopic activity of the ventricles – LVPs were found in 77 % vs. 33 % in individuals without SH (P = 0.0001), changes in the electrical properties of ventricles in AH patients with concomitant SH were also associated with an increase in the number of premature ventricular contractions by 6.69 times (from 42.56 ± 36.96 to 441.53 ± 1414.97, P = 0.026) compared with the same index in patients with AH without concomitant SH, indicating the negative effect of SH on the electrical properties of the ventricles.Conclusions. In patients with stage II arterial hypertension in comparison to relatively healthy subjects, indicators that characterize the late potentials of the atria and ventricles are significantly changed, which is accompanied by an increase in the number of supraventricular and ventricular rhythm disorders. Subclinical hypothyroidism causes an additional pro-arrhythmic effect on the ventricular myocardium in arterial hypertension., Поздние потенциалы предсердий (ППП) и желудочков (ППЖ) – неинвазивные электрокардиографические критерии наличия высокой аритмической готовности и риска появления опасных для жизни аритмий. Электрические свойства миокарда у больных гипертонической болезнью II стадии, сочетанной с субклиническим гипотиреозом, ранее не изучали.Цель работы – исследовать изменения электрических свойств миокарда предсердий и желудочков у больных с артериальной гипертензией, сочетанной с субклиническим гипотиреозом (СГ).Материалы и методы. После подписания информированного согласия в исследование включены 122 больных гипертонической болезнью (ГБ) II стадии и 16 практически здоровых лиц. Критерии включения в исследование: наличие АГ II стадии без тиропатий и сочетанной с СГ (для больных основной группы). В зависимости от уровня тиреотропного гормона (ТТГ) пациенты с ГБ разделены на 2 группы: с нормальным (0,4–4,0 мкЕД/мл) и умеренно повышенным уровнем ТТГ (4,0–15,6 мкЕД/мл, при нормальном уровне тиреоидных гормонов). В группу больных гипертонической болезнью без СГ вошли 92 пациента (75 женщин – 81,52 %, 17 мужчин – 18,48 %), в группу больных ГБ с сопутствующим СГ включены 30 пациентов (26 женщин – 86,7 %, 4 мужчины – 13,3 %). Всем больным выполнено суточное мониторирование АД и ЭКГ (комбинированный монитор ЭКГ и АД «Кардиотехника-04-АД-3», Санкт-Петербург, РФ). Использовали фильтр со срезом 40 Гц, запись – в ортогональных отведениях X, Y, Z по Симпсону. Обработка данных проведена с помощью программы Statistica 6.0. Данные представлены в виде медианы и межквартильного размаха Ме (25 %; 75 %).Результаты. У больных ГБ без сопутствующего СГ, в отличие от практически здоровых лиц, отмечено преобладание поздних предсердных потенциалов (63 % против 84 %; р = 0,0419) с ростом в 16,4 раза (р = 0,018) количества наджелудочковых экстрасистол. Также у больных ГБ без сопутствующего СГ поздние потенциалы желудочков отмечают в 5,7 раза чаще (6 % против 34 %, р = 0,0302), они ассоциируются с достоверным (р = 0,004) увеличением количества желудочковых экстрасистол.У больных ГБ с сопутствующим субклиническим гипотиреозом, в отличие от практически здоровых лиц, значительно преобладала предсердная эктопическая активность (ППП обнаружены у 87 %, против 63 %, р = 0,0498), что сопровождалось закономерным ростом в 27,2 раза (р = 0,038) количества наджелудочковых экстрасистол, и эктопическая активность желудочков. Изменения электрических свойств желудочков сопровождались увеличением удельного веса установленных ППЖ (77 % против 6 %, р = 0,0001), которое ассоциировалось с достоверным (р = 0,001) увеличением количества желудочковых экстрасистол в сутки у этой категории больных (441,53 ± 1414, 97 против 0,00 ± 0,00 у практически здоровых лиц, р = 0,001).Больные ГБ с и без сопутствующего СГ не различались по показателям, которые характеризуют поздние потенциалы предсердий. Не установлена также статистически достоверная разница показателей количества наджелудочковых экстрасистол (р = 0,527), парных наджелудочковых экстрасистол (р = 0,449), групповых наджелудочковых экстрасистол (р = 0,314). Однако у больных ГБ с сопутствующим субклиническим гипотиреозом наблюдали достоверное повышение эктопической активности желудочков: ППЖ отмечены у 77 % против 33 % у лиц без СГ (р = 0,0001), изменения электрических свойств желудочков у больных ГБ с сопутствующим субклиническим гипотиреозом также ассоциировались с ростом количества желудочковых экстрасистол в 6,69 раза (с 42,56 ± 36,96 до 441,53 ± 1414,97, р = 0,026) по сравнению с аналогичным показателем у больных ГБ без сопутствующего СГ, что свидетельствует об отрицательном влиянии СГ на электрические свойства миокарда желудочков.

Atrial arrhythmias occur at a higher than expected prevalence amongst endurance athletes. Few studies have examined both atrial structure and arrhythmias in middle-aged endurance athletes. We examined the relationship between P-wave duration, atrial dimensions, and the presence of atrial ectopy in long-standing, middle-aged endurance athletes.Middle-aged athletes with a minimum of 10 years of competitive endurance sport history and no history of structural heart disease or clinical atrial arrhythmias, had 12-lead ECGs to assess P-wave duration, signal-averaged ECGs (SAECG) to assess filtered P-wave duration, a 24 h Holter monitor to assess atrial ectopy, and echocardiography and cardiac magnetic resonance imaging to assess atrial structural characteristics.Amongst endurance athletes (n = 104; mean age = 54 ± 5 years; 63% male), filtered P-wave duration on SAECG was correlated with P-wave duration on 12-lead ECG (r = 0.36, p, 0.0001), as well as with larger CMR-derived RA areas (r = 0.30, p = 0.01) and volumes (r = 0.24, p 0.05). There was no correlation between filtered P-wave duration and any LA measures on imaging (p 0.05). There was no correlation between the incidence of atrial ectopy (premature atrial contractions or atrial tachycardia) and any electrocardiographic or structural measures.Longer filtered P-wave duration was associated with larger RA areas and volumes, without an increase in atrial ectopy.

BackgroundLow resting heart rate and premature atrial contractions (PACs) predict incident atrial fibrillation (AF) and could be interdependent, since PACs occur in the gaps between normal beats.ObjectiveTo study the association between low heart rate at 24hECG, PACs and incident AF in a prospective population-based cohort.MethodsIn the Malmö Diet and Cancer study, 24hECGs were performed in 377 AF-free subjects. The endpoint was clinical AF retrieved from national hospital (mean follow-up 17 years). The interaction between increased supraventricular activity (SVA) top quartile of either PACs/hour or supraventricular tachycardias/hour) and mean heart rate (mHR) as regards AF risk was assessed in multivariable Cox regression analyses adjusted for age, sex, height, BMI, systolic blood pressure, antihypertensive medication, smoking and homeostasis model assessment of insulin resistance.ResultsThere were 80 (21%) incident cases of AF. Below median mHR (80 bpm/75 bpm for women/men) was associated with increased AF incidence (HR: 1.89, 95% CI 1.18 to 3.02, p=0.008). There was no correlation between mHR and SVA (p=0.6) or evidence of a multiplicative interaction between these factors for AF risk (p for interaction=0.6) In the group with both increased SVA and below median mHR (17% of the population) the relative risk of AF was very high (HR 4.5, 95% CI 2.2 to 9.1, p=0.001).ConclusionLow mHR at 24hECG independently predicts AF, but there is no association between mHR and SVA, and these factors are independent as regards AF risk. Subjects with both low mHR and increased SVA have high AF risk.

INTRODUCTION Frequent premature ventricular contractions (PVCs) can cause cardiomyopathy (CM). Postextrasystolic potentiation (PESP) and irregularity have been in implicated as triggers of PVC-CM. Because both phenomena can also be found in premature atrial contractions (PACs), it is speculated that frequent PACs have similar consequences. METHODS AND RESULTS A single-center, retrospective study included all consecutive patients undergoing a 14-day Holter monitors (November 2014 to October 2016). Patients were divided into four groups by ectopy burden group 1 (

Arrhythmia-induced cardiomyopathy has been reported with a range of sustained supraventricular tachycardia including atrial fibrillation, atrial tachycardia, inappropriate sinus tachycardia,1 dual atrioventricular nodal nonreentrant tachycardia,2 and double fire tachycardia, as well as frequent premature ventricular contractions (PVCs).3 Although the hallmark of both tachycardia-mediated and PVC-induced cardiomyopathy is resolution upon treating the inciting arrhythmia,4 underlying mechanisms likely differ based on differing time course of onset and associated structural changes.5, 6 We present a patient with frequent symptomatic premature atrial contractions (PACs) who had normalization of left ventricular (LV) systolic dysfunction upon successful PAC catheter ablation. To date, we are aware of only one prior report of PAC-mediated cardiomyopathy.7

This article reviews important features for improving the diagnosis and management of fetal arrhythmias. The normal fetal heart rate ranges between 110 and 160 beats per minute. A fetal heart rate is considered abnormal if the heart rate is beyond the normal ranges or the rhythm is irregular. The rate, duration, and origin of the rhythm and degree of irregularity usually determine the potential for hemodynamic consequences. Most of the fetal rhythm disturbances are the result of premature atrial contractions (PACs) and are of little clinical significance. Other arrhythmias include tachyarrhythmias (heart rate in excess of 160 beats/min) such as atrioventricular (AV) reentry tachycardia, atrial flutter, and ventricular tachycardia, and bradyarrhythmias (heart rate

Aims Premature atrial contractions (PACs) are a common cardiac phenomenon, traditionally considered to be of little clinical significance. Recent studies, however, suggest that PACs are associated with atrial fibrillation (AF), as well as ischaemic stroke, transient ischaemic attack, and mortality. This systematic review aims to investigate the association between PACs on standard electrocardiogram (ECG) as well as PAC-count on Holter monitor and future detection of AF, brain ischaemia, and all-cause mortality in patients without a history of AF. Methods and results We searched PubMed, Embase (OVID), and Cochrane Database of Systematic Reviews from inception through 11 April 2018 and performed a systematic review and meta-analysis. We assessed risk of bias using a modified Quality In Prognosis Studies tool. The primary expression of associations in meta-analysis was the unadjusted hazard ratio (HR) using a random effects model. We identified 33 eligible studies including 198 876 patients from Western and East Asian populations with mean age ranging 52-76 years. Frequent PACs on 24-48 h Holter was associated with AF [HR 2.96, 95% confidence interval (CI) 2.33-3.76; 15 cohorts, n = 16 613], first stroke (HR 2.54, 95% CI 1.68-3.83; 3 cohorts, n = 1468), and all-cause mortality (HR 2.14, 95% CI 1.94-2.37; 6 cohorts, n = 7571). There was insufficient evidence to conclude that presence of ≥1 PAC on standard 12-lead ECG is associated with future AF detection. Conclusion In older patients without a history of AF, frequent PACs on 24-48 h Holter are significantly associated with AF, first stroke, and mortality.

Background: The aim of the study was to evaluate the impact of premature atrial contractions (PACs) burden, and the presence of non-sustained ventricular tachycardia (NSVT) on prognosis and type of major adverse cardiovascular events in patients with frequent premature ventricular contractions (PVCs). Methods: We retrospectively studied 285 consecutive patients with frequent PVCs defined as PVC count equal or higher than 1% of total beats assessed with 24-h Holter recording. Patients with atrial fibrillation (AF) were excluded. We evaluated the impact of PAC burden and the presence of NSVT on the primary end points of all-cause mortality, stroke and new-onset AF, and secondary end points; arrhythmic end point (arrhythmic death or hospitalizations for ventricular arrhythmias) or heart failure (HF)-related end point (death or hospitalizations due to HF). Results: The PAC number showed an adjusted hazard ratio (HR) (95% confidence interval (CI), P value) of 1.077 (1.014 - 1.145, P = 0.017) for all-cause mortality, 1.250 (1.080 - 1.447, P = 0.003) for stroke, 1.090 (1.006 - 1.181, P = 0.036) for new-onset AF and 1.376 (1.128 - 1.679, P = 0.002) for the HF end point. The presence of NSVT showed an adjusted HR (95% CI) of 3.644 (1.147 - 11.57, P = 0.028) for the arrhythmic end point. Conclusions: In patients with frequent PVCs a high PAC count was independently associated with increased mortality, higher rate of AF, stroke and HF adverse events, but not with arrhythmic adverse events. The presence of NSVT was independently associated with increased arrhythmic adverse events, but not with overall mortality, AF, stroke or HF events. Cardiol Res. 2019;10(5):268-277 doi: https://doi.org/10.14740/cr935

Background: AMAZFIT®, a novel wearable electrocardiogram (ECG)-recording system is used for the measurement, acquisition, and storage of single-lead cardiac waveforms for adults. The aim of the study was to evaluate the accuracy of AMAZFIT® for diagnosing arrhythmia in older patients.Methods: From May to December 2019, we recruited 291 elderly individuals with an average age of 78±10 years old, and 41.9% women. All cardiac waveforms were obtained from the AMAZFIT® which included limb and chest leads. Two trained technicians reviewed all ECG data to determine cardiac rhythm using standard diagnostic criteria. We evaluated the accuracy of AMAZFIT® for identifying arrhythmia by comparing the sensitivity, specificity, accuracy, positive predictive value (PPV), negative predictive value (NPV), and positive and negative likelihood ratios with those of a standard 12-lead ECG.Results: Of the 291 participants, 197 older adults had arrhythmias, including AF (n = 119), first-degree AVB (n = 28), PACs (n = 25), and PVCs (n = 28). Three of these participants had arrhythmias of AF and PVCs. Chest lead data from 100% and limb lead data from 4.7% of the participants were analyzed. An evaluation of AMAZFIT® for atrial fibrillation (AF) reported a sensitivity, specificity, PPV, NPV PLR, and negative likelihood ratio (NLR) of 93.28, 95.35, 93.28, 95.35, 20.06, and 0.07%, respectively. AMAZFIT® also demonstrated excellent sensitivity for premature atrial contractions (PACs) (84.00%) and premature ventricular contractions (PVCs) (89.29%). However, the device demonstrated a low sensitivity for first-degree atrioventricular block (32.14%).Conclusions: The AMAZFIT® showed significantly higher sensitivity and specificity for AF, PACs, and PVCs. This portable ECG-recording device based on an algorithm has a potential auxiliary diagnostic value for identifying arrhythmia compared with a standard 12-lead ECG device.

The relationship between premature atrial complexes (PACs) and atrial fibrillation (AF), stroke and myocardium degradation is unclear. Current PAC detectors are beat classifiers that attain low sensitivity on PAC detection. The lack of a proper PAC detector hinders the study of the implications of this event and its monitoring. In this work a PAC and ventricular detector is presented. Two PhysioNet open-source databases were used: the long-term ST database (LTSTDB) and the supraventricular arrhythmia database (SVDB). A combination of heart rate variability (HRV) and morphological features were used to classify beats. Morphological features were extracted from the ECG as well as on the 4th scale of the discrete wavelet transform (DWT). After feature selection, a random forest algorithm was trained for a binary classification of PAC (S) vs. others and for a multi-labels classification to discriminate between normal (N), S and ventricular (V) beats. The algorithm was tested in a 10-fold cross-validation following a patient-wise train-test division (i.e., no beats belonging to the same patient were included both in the test and train set). The resultant median sensitivity, specificity and positive predictive value (PPV) were 99.29, 99.54, and 100% for (N), 95.83, 99.39, and 35.68% for (S), 100, 99.90, and 79.63% for (V). The proposed method attains a greater PAC and ventricular beat sensitivity and PPV than the state-of-the-art classifiers.

Rationale: Recent studies have shown that QT interval prolongation is associated with disease severity and predicts mortality in systemic inflammatory diseases, particularly rheumatoid arthritis. Systemic pro-inflammatory cytokines released from synovial tissues in rheumatoid arthritis, such as interleukin (IL)-1β, IL-6, and tumor necrosis factor-α, could have direct effects on cardiac electrophysiology, particularly changes in the expression and function of potassium and calcium channels, resulting in QT interval prolongation on surface electrocardiogram (ECG) and an increased predisposition to develop lethal ventricular arrhythmias. However, reports on torsade de pointes (TdP) due to acquired long QT syndrome in patients with polymyalgia rheumatica (PMR) are limited. Patient concerns: An 85-year-old Japanese woman with active PMR developed first syncope. Diagnosis: Frequent premature atrial contractions (PACs) with multiple patterns of aberrant conduction, QT interval prolongation, and morphological T-U wave variability followed by TdP were documented. PACs were the first beat of TdP. Interventions: Amiodarone, together with magnesium and potassium, was intravenously administered. However, TdP resulted in a ventricular arrhythmic storm, for which sedation with mechanical ventilatory support, temporary overdrive cardiac pacing, and intravenous landiolol administration in addition to multiple direct current shocks were effective. Outcomes: Approximately 2 years later, the patient was treated with amiodarone, propranolol, and prednisolone. She did not undergo implantable cardioverter-defibrillator implantation and was quite well, with no recurrence of ventricular tachyarrhythmia. Lessons: IL-6 hyperproduction in inflamed tissues has been widely confirmed in PMR. Frequent PACs with various patterns of aberrant conduction, QT interval prolongation, and morphological T-U wave variability followed by TdP, for which IL-6-mediated enhancement of L-type Ca2+ current and inhibition of the rapid component of the delayed rectifier K+ current are the most likely mechanisms, were documented in an elderly Japanese woman with PMR. ECG may be recorded once in patients with active PMR even when these patients do not complain of palpitation or syncope. If QT interval prolongation or arrhythmia, including even PACs, is observed, follow-up ECG may be warranted, particularly for patients with some risk factors for QT prolongation that could lead to TdP, such as advanced age, female sex, hypopotassemia, and polypharmacy.

There are few reports on head-to-head comparisons of electrocardiogram (ECG) monitoring between adhesive single-lead and Holter devices for arrhythmias other than atrial fibrillation (AF). This study aimed to compare 24 h ECG monitoring between the two devices in patients with general arrhythmia. Twenty-nine non-AF patients with a workup of pre-diagnosed arrhythmias or suspicious arrhythmic episodes were evaluated. Each participant wore both devices simultaneously, and the cardiac rhythm was monitored for 24 h. Selective ECG parameters were compared between the two devices. Two cardiologists independently compared the diagnoses of each device. The two most frequent monitoring indications were workup of premature atrial contractions (41.4%) and suspicious arrhythmia-related symptoms (37.9%). The single-lead device had a higher noise burden than the Holter device (0.04 ± 0.05% vs. 0.01 ± 0.01%, p = 0.024). The number of total QRS complexes, ventricular ectopic beats, and supraventricular ectopic beats showed an excellent degree of agreement between the two devices (intraclass correlation coefficients = 0.991, 1.000, and 0.987, respectively). In addition, the minimum/average/maximum heart rates showed an excellent degree of agreement. The two cardiologists made coherent diagnoses for all 29 participants using both monitoring methods. In conclusion, the single-lead adhesive device could be an acceptable alternative for ambulatory ECG monitoring in patients with general arrhythmia.

Introduction : A single-lead electrocardiogram (EKG) is routinely recorded with electroencephalogram (EEG). This study investigates the frequency and types of EKG abnormalities during routine EEG. Methods : All routine EEGs (20–60 min) over one year were retrospectively analyzed. A blinded cardiologist interpreted EKG recordings. An epileptologist evaluated EEGs. Demographic data, underlying comorbidities, and indications for the EEG were extracted. Results : A total of 433 recordings for 365 patients were included. Mean (±SD) age was 46.8 (±21.3) years and 50.4% were females. EKG abnormalities were detected in 28.5% of patients; sinus tachycardia (11%), premature ventricular contractions (7.9%), atrial fibrillation (Afib) (6.3%), sinus bradycardia (2.2%) and premature atrial contractions (1.1%). Afib was more common in females than males (p = 0.020), confirmed in six out of seven patients and discovered in 17 patients. Age (OR: 1.67, 95%CI: 1.05–2.66, p = 0.031), prior diagnosis of epilepsy (OR: 2.25, 95% CI: 1.22 – 4.14, p = 0.009), history of seizure (OR: 1.97, 95%CI: 1.09–3.54, p = 0.024), abnormal EEG (OR: 2.14, 95%CI: 1.25 – 3.66, p = 0.005) and EEGs evaluating seizures/epilepsy (OR: 4.18, 95% CI: 1.32 – 13.21, p = 0.015) or syncope (OR: 3.21, 95% CI: 1.16 – 8.84, p = 0.024) were independently associated with abnormal EKG. Conclusion : The frequency of EKG abnormalities captured during routine EEGs was high, with Afib being the most significant. Older age, history of epilepsy or seizure, abnormal EEGs, and EEGs evaluating seizures/epilepsy or syncope were significant predictors. These findings suggest neurologists to become more vigilant to EKG recorded during routine EEG as such findings might have diagnostic and therapeutic implications.

Background Frequent supraventricular arrhythmia is associated with increased incidence of atrial fibrillation. However, it is unknown whether the prognostic significance of supraventricular arrhythmia is modified by plasma levels of N-terminal pro-brain natriuretic peptide (NT-proBNP) or troponin T (TnT). This study examined the interrelationships between NT-proBNP, TnT levels and frequent supraventricular arrhythmia, and whether these biomarkers and a measure of frequent supraventricular arrhythmia could improve risk assessment for incidence of AF. Methods Supraventricular extrasystoles (SVEs) and supraventricular tachycardias were assessed from 24-h electrocardiograph recordings in 373 individuals initially without AF. Elevated NT-pro-BNP, TnT and SVEs was defined as a measurement in the top quartile of the study population distribution. Incident cases of AF were retrieved by linkage with the Swedish National Patient Register. Results During a mean follow-up of 15.4 years, 88 subjects had a diagnosis of AF. After multivariable adjustment, individuals with both elevated NT-proBNP and frequent SVEs had a significantly increased incidence of AF, compared to subjects without elevated NT-proBNP or frequent SVEs (hazard ratio (HR) 4.61, 95% confidence interval (CI) 2.45–8.69), and compared to individuals with either elevated NT-proBNP or frequent SVEs (both P P = 0.015). Conclusion Subjects with both elevated NT-proBNP and frequent SVEs have substantially increased risk of AF, and the use of these variables could improve long-term prediction of incident AF.

Background and ObjectiveTo identify clinical, ECG, and blood-based biomarkers associated with atrial fibrillation (AF) detection after ischaemic stroke or TIA that could help inform patient selection for cardiac monitoring.MethodsWe performed a systematic review and meta-analysis and searched electronic databases for cohort studies from January 15, 2000, to January 15, 2020. The outcome was AF ≥30 seconds within 1 year after ischemic stroke/TIA. We used random effects models to create summary estimates of risk. Risk of bias was assessed using the Quality in Prognostic Studies tool.ResultsWe identified 8,503 studies, selected 34 studies, and assessed 69 variables (42 clinical, 20 ECG, and 7 blood-based biomarkers). The studies included 11,569 participants and AF was detected in 1,478 (12.8%). Overall, risk of bias was moderate. Variables associated with increased likelihood of AF detection are older age (odds ratio [OR] 3.26, 95% confidence interval [CI] 2.35–4.54), female sex (OR 1.47, 95% CI 1.23–1.77), a history of heart failure (OR 2.56, 95% CI 1.87–3.49), hypertension (OR 1.42, 95% CI 1.15–1.75) or ischemic heart disease (OR 1.80, 95% CI 1.34–2.42), higher modified Rankin Scale (OR 6.13, 95% CI 2.93–12.84) or National Institutes of Health Stroke Scale score (OR 2.50, 95% CI 1.64–3.81), no significant carotid/intracranial artery stenosis (OR 3.23, 95% CI 1.14–9.11), no tobacco use (OR 1.93, 95% CI 1.48–2.51), statin therapy (OR 2.07, 95% CI 1.14–3.73), stroke as index diagnosis (OR 1.59, 95% CI 1.17–2.18), systolic blood pressure (OR 1.61, 95% CI 1.16–2.22), IV thrombolysis treatment (OR 2.40, 95% CI 1.83–3.16), atrioventricular block (OR 2.12, 95% CI 1.08–4.17), left ventricular hypertrophy (OR 2.21, 95% CI 1.03–4.74), premature atrial contraction (OR 3.90, 95% CI 1.74–8.74), maximum P-wave duration (OR 3.19, 95% CI 1.40–7.25), PR interval (OR 2.32, 95% CI 1.11–4.83), P-wave dispersion (OR 7.79, 95% CI 4.16–14.61), P-wave index (OR 3.44, 95% CI 1.87–6.32), QTc interval (OR 3.68, 95% CI 1.63–8.28), brain natriuretic peptide (OR 13.73, 95% CI 3.31–57.07), and high-density lipoprotein cholesterol (OR 1.49, 95% CI 1.17–1.88) concentrations. Variables associated with reduced likelihood are minimum P-wave duration (OR 0.53, 95% CI 0.29–0.98), low-density lipoprotein cholesterol (OR 0.73, 95% CI 0.57–0.93), and triglyceride (OR 0.51, 95% CI 0.41–0.64) concentrations.DiscussionWe identified multimodal biomarkers that could help guide patient selection for cardiac monitoring after ischaemic stroke/TIA. Their prognostic utility should be prospectively assessed with AF detection and recurrent stroke as outcomes.

Background Cardiovascular events have been reported in the setting of coronavirus disease‐19 (COVID‐19). It has been hypothesized that systemic inflammation may aggravate arrhythmias or trigger new‐onset conduction abnormalities. However, the specific type and distribution of electrocardiographic disturbances in COVID‐19 as well as their influence on mortality remain to be fully characterized. Methods Electrocardiograms (ECGs) were obtained from 186 COVID‐19‐positive patients at a large tertiary care hospital in Northern Nevada. The following arrhythmias were identified by cardiologists: sinus bradycardia, sinus tachycardia, atrial fibrillation (A‐Fib), atrial flutter, multifocal atrial tachycardia (MAT), premature atrial contraction (PAC), premature ventricular contraction (PVC), atrioventricular block (AVB), and right bundle branch block (RBBB). The mean PR interval, QRS duration, and corrected QT interval were documented. Fisher's exact test was used to compare the ECG features of patients who died during the hospitalization with those who survived. The influence of ECG features on mortality was assessed with multivariable logistic regression analysis. Results A‐Fib, atrial flutter, and ST‐segment depression were predictive of mortality. In addition, the mean ventricular rate was higher among patients who died as compared to those who survived. The use of therapeutic anticoagulation was associated with reduced odds of death; however, this association did not reach statistical significance. Conclusion The underlying pathogenesis of COVID‐19‐associated arrhythmias remains to be established, but we postulate that systemic inflammation and/or hypoxia may induce potentially lethal conduction abnormalities in affected individuals. Longitudinal studies are warranted to evaluate the risk factors, pathogenesis, and management of COVID‐19‐associated cardiac arrhythmias.

The presence of bradycardic arrhythmias during volitional apnea at altitude may be caused by chemoreflex activation/sensitization. We investigated whether bradyarrhythmic episodes became prevalent in apnea following short‐term hypoxia exposure. Electrocardiograms (ECG; lead II) were collected from 22 low‐altitude residents (F = 12; age=25 ± 5 years) at 671 m. Participants were exposed to normobaric hypoxia (Spo 2 ~79 ± 3%) over a 5‐h period. ECG rhythms were assessed during both free‐breathing and maximal volitional end‐expiratory and end‐inspiratory apnea at baseline during normoxia and hypoxia exposure (20 min [AHX]; 5 h [HX5]). Free‐breathing HR became elevated at AHX (78 ± 10 bpm; p, In this study, voluntary apnea was used to determine whether significant chemoreceptor sensitivity develops following 5 h of normobaric hypoxia, as evident through significant bradycardia and arrhythmogenesis. The results showed that bradycardia and the incidence of arrhythmogenesis was similar between initial hypoxia exposures, as well as after 5 h of exposure. These findings demonstrate previously documented bradyarrhythmogenesis is a unique phenomenon to chronic hypoxia exposure (i.e., several days residency at altitude).

The medical community's understanding of the consequences of premature ventricular contractions (PVCs) and PVC-induced cardiomyopathy has been derived mostly from observational and large population-based studies. Due to the difficulty of predicting the development of PVC-cardiomyopathy, the acute and chronic cardiac effects of PVCs and the mechanism of PVC-cardiomyopathy have been derived from pre-clinical studies with large animal models. Recently, these studies have described myocardial substrates that could potentially increase morbidity and mortality in patients with frequent PVCs and PVC-cardiomyopathy. In this paper, we provide an up-to-date comprehensive review of these pre-clinical and clinical studies.