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Premature ventricular contraction (PVC) burden is a risk factor for heart failure and cardiovascular death in patients with structural heart disease. Long-term electrocardiographic monitoring can have a significant impact on PVC burden evaluation by further defining PVC distribution patterns. This study aimed to ascertain the optimal duration of electrocardiographic monitoring to characterize PVC burden and to understand clinical characteristics associated with frequent PVCs and nonsustained ventricular tachycardia in a large US cohort. Commercial data (iRhythm's Zio patch) from June 2011 to April 2022 were analyzed. Inclusion criteria were age >18 years, PVC burden ≥5%, and wear period ≥13 days. PVC burden cutoffs were determined on the basis of AHA/ACC/HRS guidelines for very frequent PVCs (10,000–20,000 during 24 hours). Patients were assigned to categories by PVC densities: low, <10%; moderate, 10% to <20%; and high, ≥20%. Mean measured error was assessed at baseline and daily until the wear period's end for overall PVC burden and different PVC densities. Analysis of 106,705 patch monitors revealed a study population with mean age of 70.6 ± 14.6 years (33.6% female). PVC burden was higher in male patients and those >65 years of age. PVC burden mean error decreased from 2.9% at 24 hours to 1.3% at 7 days and 0.7% at 10 days. Number of ventricular tachycardia episodes per patient increased with increasing PVC burden (P <.0001). Extending ambulatory monitoring beyond 24 hours to 7 days or more improves accuracy of assessing PVC burden. Ventricular tachycardia frequency and duration vary by initial PVC density, highlighting the need for prolonged cardiac monitoring. [ABSTRACT FROM AUTHOR]

This research is aimed at evaluating the efficacy and safety of ablation of ventricular tachyarrhythmias using high-density mapping in patients with non-ischemic etiology. This study analyzed 60 patients with ventricular tachyarrhythmias, using diagnostic tools like electrocardiography and MRI. Treatment involved epicardial ablation following the E. Sosa method, with efficacy evaluated through the SF-36 survey and MRI. Success rates were categorized, and post-treatment care included troponin monitoring and aspirin. Data was analyzed using Excel and Statistika 11.0. Of the 60 patients, 30 underwent surgery at the City Cardiological Center in Almaty and 30 patients were operated on at the National Research Cardiac Surgery Center in Astana. Prior to surgery, all patients underwent a standard clinical diagnostic examination followed by ablation of ventricular tachyarrhythmias using high-density mapping. After six and 12 months from the beginning of the study, all patients underwent a follow-up examination, with an assessment of the effectiveness of the above treatment. After 12 months, follow-up examination of patients showed good results. Left ventricular ejection fraction in patients after 12 months increased from 47 ± 2.4 to 58 ± 4.5%. The end-diastolic diameter of the left ventricle decreased from 61.2 ± 2.31 to 50.1 ± 1.9 mm. In summary, the study highlights the efficacy and safety of high-density mapping ablation in treating ventricular tachyarrhythmias, especially from the right ventricular outflow tract in patients with reduced left ventricular ejection fraction. The success rate of the procedure was 95%. This approach proves beneficial for patients unresponsive to antiarrhythmic therapy, enhancing both the quality of life and potentially reducing mortality in patients with ventricular arrhythmias. [ABSTRACT FROM AUTHOR]

Despite impressive developments in the field of ventricular arrhythmias, there is still a relevant number of patients with ventricular arrhythmias who require antiarrhythmic drug therapy and may, e.g., in otherwise drug and/or ablation refractory situations, benefit from agents known for decades, such as mexiletine. Through its capability of blocking fast sodium channels in cardiomyocytes, it has played a minor to moderate antiarrhythmic role throughout the recent decades. Nevertheless, certain patients with structural heart disease suffering from drug-refractory, i.e., mainly amiodarone refractory ventricular arrhythmias, as well as those with selected forms of congenital long QT syndrome (LQTS) may nowadays still benefit from mexiletine. Here, we outline mexiletine's cellular and clinical electrophysiological properties. In addition, the application of mexiletine may be accompanied by various potential side effects, e.g., nausea and tremor, and is limited by several drug-drug interactions. Thus, we shed light on the current therapeutic role of mexiletine for therapy of ventricular arrhythmias and discuss clinically relevant aspects of its indications based on current evidence. [ABSTRACT FROM AUTHOR]

Background: The occurrence of ventricular tachyarrhythmias represents an established risk factor of mortality in heart failure (HF). However, data concerning their prognostic impact in heart failure with mildly reduced ejection fraction (HFmrEF) is limited. Therefore, the present study aims to investigate patient characteristics associated with ventricular tachyarrhythmias and their prognostic impact in patients with HFmrEF. Methods: Consecutive patients hospitalized with HFmrEF (i.e., left ventricular ejection fraction 41–49% and signs and/or symptoms of HF) were retrospectively included at one institution from 2016 to 2022. The prognosis of patients with HFmrEF and different types of ventricular tachyarrhythmias (i.e., non-sustained ventricular tachycardia (nsVT), sustained VT (sVT), and ventricular fibrillation (VF) was investigated for the primary endpoint of long-term all-cause mortality at 30 months. Secondary endpoints included in-hospital all-cause mortality and long-term HF-related rehospitalization at 30 months. Results: From a total of 2184 patients with HFmrEF, 4.4% experienced ventricular tachyarrhythmias (i.e., 2.0% nsVT, 0.7% sVT, and 1.6% VF). The occurrence of nsVT was associated with higher New York Heart Association (NYHA) functional class, whereas the incidence of sVT/VF was associated with acute myocardial infarction and ischemic heart disease. However, nsVT (25.0%; HR = 0.760; 95% CI 0.419–1.380; p = 0.367) and sVT/VF (28.8%; HR = 0.928; 95% CI 0.556–1.549; p = 0.776) were not associated with a higher risk of long-term all-cause mortality compared to patients with HFmrEF without ventricular tachyarrhythmias (31.5%). In-hospital cardiovascular mortality was more frequently observed in patients with HFmrEF and sVT/VF compared to those with HFmrEF but without sustained ventricular tachyarrhythmias (7.7% vs. 1.5%; p = 0.004). Finally, the risk of rehospitalization for worsening HF was not affected by the presence of ventricular tachyarrhythmias. Conclusions: The occurrence of ventricular tachyarrhythmias in patients hospitalized with HFmrEF was low and not associated with long-term prognosis. [ABSTRACT FROM AUTHOR]

Implantable cardioverter‐defibrillators (ICDs) have revolutionized the prognosis for patients at elevated risk of ventricular tachyarrhythmias. For safety, defibrillation should be effective with a minimum of 10 J below the device's maximum energy. While modern ICDs rarely deliver ineffective shocks in primary prevention, the surge in managing severe heart failure patients has led to an increased number of patients with high defibrillation thresholds (DFTs). This article elucidates the potential causes of high DFT, including clinical factors, lead and device placement, the presence of a Left Ventricular Assist Device (LVAD), prolonged ventricular arrhythmias, shock vectors, waveform tilt, medications, and manufacturer‐specific options. We also detail management strategies, highlighting alternative shock coil placements, practical recommendations, and case studies from our institution. Our management algorithm suggests addressing preventable causes, re‐evaluating coil positions, considering non‐invasive system modifications, upgrading to a higher‐capacity device, and adding extra coil(s). [ABSTRACT FROM AUTHOR]

Cardiac sarcoidosis (CS), a rare condition characterized by non-caseating granulomas, can manifest with symptoms such as atrioventricular block and ventricular tachycardia (VT), as well as mimic inherited cardiomyopathies. A 48-year-old male presented with recurrent VT. The initial 18F-fluorodeoxyglucose positron emission tomography (18FDG-PET) scan showed uptake of the mediastinal lymph node. Cardiovascular magnetic resonance (CMR) demonstrated intramyocardial fibrosis. The follow-up 18FDG-PET scan revealed the presence of tracer uptake in the left ventricular (LV) septum, suggesting the likelihood of CS. Genetic testing identified a pathogenic LMNA variant. A 47-year-old female presented with complaints of palpitations and syncope. An Ajmaline provocation test confirmed Brugada syndrome (BrS). CMR revealed signs of cardiac inflammation. An endomyocardial biopsy (EMB) confirmed the diagnosis of cardiac sarcoidosis. Polymorphic VT was induced during an electrophysiological study, and an implantable cardioverter-defibrillator (ICD) was implanted. A 58-year-old woman presented with sustained VT with a prior diagnosis of hypertrophic cardiomyopathy (HCM). A genetic work-up identified the presence of a heterozygous MYBC3 variant of unknown significance (VUS). CMR revealed late gadolinium enhancement (LGE), while the 18FDG-PET scan demonstrated LV tracer uptake. The immunosuppressive therapy was adjusted, and no further VTs were observed. A 28-year-old male athlete with right ventricular dilatation and syncope experienced a cardiac arrest during training. Genetic testing identified a pathogenic mutation in PKP2. The autopsy has confirmed the presence of ACM and a distinctive extracardiac sarcoidosis. Cardiac sarcoidosis and inherited cardiomyopathies may interact in several different ways, altering the clinical presentation. Overlapping pathologies are frequently overlooked. Delayed or incomplete diagnosis risks inadequate treatment. Thus, genetic testing and endomyocardial biopsies should be recommended to obtain a clear diagnosis.

Aim: To compare clinical outcomes among patients with heart failure and reduced ejection fraction (HFrEF) according to body mass index (BMI) after initiating treatment with an angiotensin‐receptor neprilysin inhibitor (ARNI). Methods: We gathered data from 2016 to 2020 at the University Medical Center Mannheim; 208 consecutive patients were divided into two groups according to BMI (< 30 kg/m2; n = 116, ≥ 30 kg/m2; n = 92). Clinical outcomes, including mortality rate, all‐cause hospitalizations and congestion, were systematically analysed. Results: At the 12‐month follow‐up, the mortality rate was similar in both groups (7.9% in BMI < 30 kg/m2 vs. 5.6% in BMI ≥ 30 kg/m2; P =.76). All‐cause hospitalization before ARNI treatment was comparable in both groups (63.8% in BMI < 30 kg/m2 vs. 57.6% in BMI ≥ 30 kg/m2; P =.69). After ARNI treatment, the hospitalization rate was also comparable in both groups at the 12‐month follow‐up (52.2% in BMI < 30 kg/m2 vs. 53.7% in BMI ≥ 30 kg/m2; P =.73). Obese patients experienced more congestion compared with non‐obese patients at follow‐up, without statistical significance (6.8% in BMI < 30 kg/m2 vs. 15.5% in BMI ≥ 30 kg/m2; P =.11). Median left ventricular ejection fraction (LVEF) improved in both groups, but significantly more in non‐obese compared with obese patients at the 12‐month follow‐up (from 26% [3%‐45%] [min.‐max.] vs. 29% [10%‐45%] [min.‐max.] [P =.56] to 35.5% [15%‐59%] [min.‐max.] vs. 30% [13%‐50%] [min.‐max.] [P =.03], respectively). The incidence of atrial fibrillation (AF), non‐sustained (ns) and sustained ventricular tachycardia (VT) and ventricular fibrillation (VF) was less in non‐obese than in obese patients after initiation of sacubitril/valsartan at the 12‐month follow‐up (AF: 43.5% vs. 53.7%; P =.20; nsVT: 9.8% vs. 28.4%; P =.01; VT: 14.1% vs. 17.9%; P =.52; VF: 7.6% vs. 13.4%; P =.23). Conclusions: The incidence of congestion in obese patients was higher compared with non‐obese patients. LVEF improved significantly more in non‐obese compared with obese HFrEF patients. Furthermore, AF and the ventricular tachyarrhythmia rate were revealed more in obesity compared with those without obesity at the 12‐month follow‐up. [ABSTRACT FROM AUTHOR]

Aim. To conduct a comparative analysis of blood biomarker concentrations, to study their prognostic role in the occurrence of sustained ventricular tachyarrhythmia (VT) or VT episodes requiring electrotherapy in patients with heart failure (HF) and left ventricular ejection fraction (LVEF) ≤35% without prior syncope or sustained ventricular arrhythmias.Material and methods. This single-center prospective clinical study included 319 patients (men, 83%) aged 57 (51-63) years with LVEF of 29 (24-33)% receiving optimal therapy for HF, hospitalized for cardioverterdefibrillator implantation for the purpose of primary prevention of sudden cardiac death. Before the procedure, the concentration of blood biomarkers (blood electrolytes, C-reactive protein, creatinine, Soluble suppression of tumorigenicity 2 (sST2), N-terminal pro-brain natriuretic peptide (NT-proBNP), galectin-3) was determined. Based on blood creatinine concentration, glomerular filtration rate was calculated using the Chronic Kidney Disease Epidemiology Collaboration equation. Patients underwent a two-year prospective follow-up to record the end point of newly occurring clinically significant VT episodes detected by an implantable cardioverter-defibrillator.Results. The studied arrhythmic endpoint occurred in 84 (26,3%) patients. The multivariate analysis revealed three blood biomarkers, the concentration of which was associated with the first manifestation of VT. With sST-2 >35 ng/ml, this risk increased by ~3 times (odds ratio (OR)=2,86; 95% confidence interval (CI): 1,23-6,64 (p=0,013)). Galectin-3 level >12 ng/ml had a comparable prognostic value (OR=2,64; 95% CI: 1,06-6,53 (p=0,032)). In case of an increase in NT-proBNP >2000 pg/ml, the risk of the same outcome was 2,2 times lower (OR=0,46; 95% CI: 0,22-0,95 (p=0,034)).Conclusion. Pre-implantation laboratory screening of NT-proBNP, sST-2 and galectin-3 concentrations can help in personalized assessment of arrhythmic risk in patients with HF and LVEF ≤35% referred for interventional primary prevention of sudden cardiac death.

Background: The role of triggers in the occurrence of appropriate implantable cardioverter‐defibrillator (ICD) shocks due to ventricular tachyarrhythmias is not well known. The aim of the study was to assess the prevalence of trigger factors in appropriate ICD shocks and to analyze their prognostic impact on clinical outcome. Methods: A total of 710 consecutive patients of a prospective single‐center ICD‐registry who received a first appropriate ICD shock between 2000 and 9/2021 were analyzed. Results: In 35% of ICD patients with first ICD shock, at least one of the following triggers was found: Ischemia (22%), Compliance (9%), Decompensation (38%), Stress (12%), Technical (5%), Electrolyte/endocrinological disorder (22%) and Medication side effects (4%). The trigger factors can be summarized under the acronym ICD‐STEMi. The prospective application of the ICD‐STEMi scheme increased the rate of identified triggers from 32% to 56% (p <.001). Patients with triggered first ICD shock had an increased 5‐year mortality rate (50% vs. 38%, p <.001). Patients with triggers did not show different mortality outcomes or recurrent ICD shocks whether they received arrhythmia therapy or not. Conclusions: The evaluation of trigger factors after the occurrence of ICD shocks is mandatory and can be systematically evaluated using the acronym ICD‐STEMi. Systematic evaluation of triggers using the ICD‐STEMi scheme can identify triggers in about half of ICD patients with first appropriate ICD shock. Patients with triggered ICD shock have a 12% higher 5‐year mortality rate. [ABSTRACT FROM AUTHOR]

Background: The natural history of chronic lymphocytic leukemia (CLL) was dramatically improved by the introduction of ibrutinib, a Bruton's tyrosine kinase (BTK) inhibitor. In this review, we aimed to summarize and critically evaluate the association between first- and second-generation BTK inhibitors and the risk of atrial fibrillation (AF) and ventricular arrhythmias (VA). Summary: Since the first clinical experience, the development of AF was observed as the result of off-target effects that likely combined with patient's predisposing risk factors and concomitant cardiac morbidities. More recently, both ibrutinib dose reduction and arrhythmia management allowed long-term treatment, with positive effects on progression-free survival and reduced all-cause mortality as well. Second-generation BTK inhibitors, acalabrutinib, and zanubrutinib have been tested and validated in CLL. A lower occurrence of AF as compared with ibrutinib has been found, although AF has always been a secondary endpoint of all studies that probed these agents. Key Messages: For this reason, caution should be exercised before concluding that second-generation BTK inhibitors are safer than ibrutinib. Recent data on the effectiveness of ibrutinib over a follow-up of 8 years show a remarkable benefit on all-cause mortality, which is of great value also for interpreting the clinical impact of the few cases of VA and sudden cardiac death (SCD) reported for ibrutinib, independently of QT lengthening. Since a risk of VA and SCD has been recently reported also during treatment with second-generation BTK inhibitors, it appears that this risk, usually reaching its maximum size effect at long-term follow-up, likely denotes a class effect of BTK inhibitors. [ABSTRACT FROM AUTHOR]

Aim. To evaluate the impact of cardiac resynchronization therapy (CRT) on the risk of sustained ventricular tachyarrhythmias (VT) in patients with heart failure (HF) with a implantable cardioverter-defibrillator (ICD) for the primary prevention of sudden cardiac death.Material and methods. This single-center prospective clinical study included 470 patients (men, 84%) with HF at the age of 57 (51-62) years with a left ventricular ejection fraction (LVEF) of 29 (25-33)%. There were following exclusion criteria: indications for cardiac surgery, known channelopathies, previously registered VT. Depending on intraventricular conduction disorders, dual-chamber ICDs (42%) or CRT-D (58%) were implanted. After ICD implantation, patients were followed up for 24 months to register the end point — a first-time sustained paroxysm of VT detected by the ICD. A positive response to CRT was established in the case of an increase in LVEF by ≥5% of the initial level.Results. A total of 388 patients underwent full postoperative follow-up. The studied arrhythmic endpoint occurred on average 21 (0,6) months after implantation in 104 patients (27%) with higher frequency in the ICD group. However, the differences in the VT rate in the study groups were statistically unreliable (30% in the ICD group versus 24% in the CRT-D group, p=0,142). It was found that the VT rate was reliably lower in CRT-responders (118 patients, 53%): 15% compared to 32% in the group of inefficient CRT. A 5% increase in the LFEF reduced the probability of VT occurrence by 3 times (odds ratio [OR]=0,34; 95% of CI: 0,13-0,86; p=002). Significant modification of arrhythmic risk was verified by increasing LFEF to 36-40% (OR=0,72; 95% CI: 0,63-0,82; p=0,04).Conclusion. The results obtained indicate that effective CRT has the potential to modify arrhythmic risk in patients with HF, especially with an increase in LVEF to the level of 36-40%.

Left ventricular hypertrophy (LVH) refers to a complex rebuilding of the left ventricle that can gradually lead to serious complications—heart failure and life-threatening ventricular arrhythmias. LVH is defined as an increase in the size of the left ventricle (i.e., anatomically), therefore the basic diagnosis detecting the increase in the LV size is the domain of imaging methods such as echocardiography and cardiac magnetic resonance. However, to evaluate the functional status indicating the gradual deterioration of the left ventricular myocardium, additional methods are available approaching the complex process of hypertrophic remodeling. The novel molecular and genetic biomarkers provide insights on the underlying processes, representing a potential basis for targeted therapy. This review summarizes the spectrum of the main biomarkers employed in the LVH valuation. [ABSTRACT FROM AUTHOR]

BackgroundImplantable cardioverter defibrillators (ICD) are effective as a primary prevention measure of ventricular tachyarrhythmias in patients with ST-segment elevation myocardial infarction (STEMI) and depressed left ventricular ejection fraction (LVEF). The implications of using cardiac magnetic resonance (CMR) instead of echocardiography (Echo) to assess LVEF prior to the indication of ICD in this setting are unknown.Materials and methodsWe evaluated 52 STEMI patients (56.6 ± 11 years, 88.5% male) treated with ICD in primary prevention who underwent echocardiography and CMR prior to ICD implantation. ICD implantation was indicated based on the presence of heart failure and depressed LVEF (≤ 35%) by echocardiography, CMR, or both. Prediction of ICD therapies (ICD-T) during follow-up by echocardiography and CMR before ICD implantation was assessed.ResultsCompared to echocardiography, LVEF was lower by cardiac CMR (30.2 ± 9% vs. 37.4 ± 7.6%, p < 0.001). LVEF ≤ 35% was detected in 24 patients (46.2%) by Echo and in 42 (80.7%) by CMR. During a mean follow-up of 6.1 ± 4.2 years, 10 patients received appropriate ICD-T (3.16 ICD-T per 100 person-years): 5 direct shocks to treat very fast ventricular tachycardia or ventricular fibrillation, 3 effective antitachycardia pacing (ATP) for treatment of ventricular tachycardia, and 2 ineffective ATP followed by shock to treat ventricular tachycardia. Echo-LVEF ≤ 35% correctly predicted ICD-T in 4/10 (40%) patients and CMR-LVEF ≤ 35% in 10/10 (100%) patients. CMR-LVEF improved on Echo-LVEF for predicting ICD-T (area under the curve: 0.76 vs. 0.48, p = 0.04).ConclusionIn STEMI patients treated with ICD, assessment of LVEF by CMR outperforms Echo-LVEF to predict the subsequent use of appropriate ICD therapies.

Despite the contemporary treatment of acute coronary syndromes, arrhythmic complications occurring prior to medical attendance remain significant, mandating in-depth understanding of the underlying mechanisms. Sympathetic activation has long been known to play a key role in the pathophysiology of ischemia-induced arrhythmias, but the regulating factors remain under investigation. Several lines of evidence implicate the endothelin system (a family of three isopeptides and two specific receptors) as an important modulator of sympathetic activation in the setting of acute coronary syndromes. Such interaction is present in the heart and in the adrenal medulla, whereas less is known on the effects of the endothelin system on the central autonomic network. This article summarizes the current state-of-the-art, placing emphasis on early-phase arrhythmogenesis, and highlights potential areas of future research. [ABSTRACT FROM AUTHOR]

Besides the diagnostic role in acute myocardial infarction, cardiac troponin I levels (cTNI) may be increased in various other clinical conditions, including heart failure, valvular heart disease and sepsis. However, limited data are available regarding the prognostic role of cTNI in the setting of ventricular tachyarrhythmias. Therefore, the present study sought to assess the prognostic impact of cTNI in patients with ventricular tachyarrhythmias (i.e., ventricular tachycardia (VT) and fibrillation (VF)) on admission. A large retrospective registry was used, including all consecutive patients presenting with ventricular tachyarrhythmias from 2002 to 2015. The prognostic impact of elevated cTNI levels was investigated for 30-day all-cause mortality (i.e., primary endpoint) using Kaplan–Meier, receiver operating characteristic (ROC), multivariable Cox regression analyses and propensity score matching. From a total of 1104 patients with ventricular tachyarrhythmias and available cTNI levels on admission, 46% were admitted with VT and 54% with VF. At 30 days, high cTNI was associated with the primary endpoint (40% vs. 22%; log rank p = 0.001; HR = 2.004; 95% CI 1.603–2.505; p = 0.001), which was still evident after multivariable adjustment and propensity score matching (30% vs. 18%; log rank p = 0.003; HR = 1.729; 95% CI 1.184–2.525; p = 0.005). Significant discrimination of the primary endpoint was especially evident in VT patients (area under the curve (AUC) 0.734; 95% CI 0.645–0.823; p = 0.001). In contrast, secondary endpoints, including all-cause mortality at 30 months and a composite arrhythmic endpoint, were not affected by cTNI levels. The risk of cardiac rehospitalization was lower in patients with high cTNI, which was no longer observed after propensity score matching. In conclusion, high cTNI levels were associated with increased risk of all-cause mortality at 30 days in patients presenting with ventricular tachyarrhythmias. [ABSTRACT FROM AUTHOR]

Limited data regarding the prognostic impact of ventricular tachyarrhythmias related to out-of-hospital (OHCA) compared to in-hospital cardiac arrest (IHCA) is available. A large retrospective single-center observational registry with all patients admitted due to ventricular tachyarrhythmias was used including all consecutive patients with ventricular tachycardia (VT) and fibrillation (VF) on admission from 2002 to 2016. Survivors discharged after OHCA were compared to those after IHCA using multivariable Cox regression models and propensity-score matching for evaluation of the primary endpoint of long-term all-cause mortality at 2.5 years. Secondary endpoints were all-cause mortality at 6 months and cardiac rehospitalization at 2.5 years. From 2.422 consecutive patients with ventricular tachyarrhythmias, a total of 524 patients survived cardiac arrest and were discharged from hospital (OHCA 62%; IHCA 38%). In about 50% of all cases, acute myocardial infarction was the underlying disease leading to ventricular tachyarrhythmias with consecutive aborted cardiac arrest. Survivors of IHCA were associated with increased long-term all-cause mortality compared to OHCA even after multivariable adjustment (28% vs. 16%; log rank p = 0.001; HR 1.623; 95% CI 1.002–2.629; p = 0.049) and after propensity-score matching (28% vs. 19%; log rank p = 0.045). Rates of cardiac rehospitalization rates at 2.5 years were equally distributed between OHCA and IHCA survivors. In patients presenting with ventricular tachyarrhythmias, survivors of IHCA were associated with increased risk for all-cause mortality at 2.5 years compared to OHCA survivors. [ABSTRACT FROM AUTHOR]

Background: Outcomes of patients with nonischemic cardiomyopathy and low ejection fraction implanted with an implantable cardioverter-defibrillator (ICD) or cardiac resynchronization therapy with a defibrillator (CRT-D), especially in contemporary, real-life cohorts, are not fully understood. Objective: We aimed to better characterize outcomes of death and ventricular tachyarrhythmias in patients with nonischemic cardiomyopathy, implanted with an ICD or CRT-D, and specifically assess differences by sex. Methods: The AnaLysIs of Both Sex and Device Specific FactoRs on Outcomes in PAtients with Non-Ischemic Cardiomyopathy (BIO-LIBRA) study was designed to prospectively assess outcomes of device-treated ventricular tachyarrhythmias and all-cause mortality events in nonischemic cardiomyopathy patients, indicated for an ICD or CRT-D implantation for the primary prevention of sudden cardiac death (SCD), with a specific focus on sex differences. We will enroll a total of 1000 subjects across 50 U.S. sites and follow patients for up to 3 years. Results: The primary objective of BIO-LIBRA is to evaluate the combined risk of all-cause mortality and treated ventricular tachycardia (VT) or ventricular fibrillation (VF) events by subject sex and by implanted device type. We will also assess all-cause mortality, VT or VF alone, cardiac death, and SCD in the total cohort, as well as by subject sex and by the implanted device type. In addition, the previously validated Seattle Proportional Risk Model (SPRM) will be used to compare the SPRM predicted incidence of SCD to the observed incidence. Conclusions: The BIO-LIBRA study will provide novel and contemporary information regarding outcomes in patients with a NICM who receive a defibrillator.

Purpose: To elucidate the electrophysiological predictors of the intramural origins of left ventricular outflow tract-ventricular tachyarrhythmias (LVOT-VAs), and to clarify the involvement of anatomical factors. Methods: Twenty-nine successfully ablated LVOT-VAs patients with origins in the aortomitral continuity (AMC) (n = 8), aortic sinus of valsalva (ASV) (n = 9), great cardiac vein (GCV) (n = 5), and intramural myocardium (n = 7) were enrolled. Intramural origins were defined as when effective ablation from AMC and epicardium (ASV and/or GCV) was needed. The local activation time difference (LATD) was calculated as follows: (earliest AMC activation) − (earliest epicardial activation), and was presented as an absolute value. Electrophysiological parameters and anatomical factors predisposing the intramural origins were investigated. Results: LATD of intramural origins was significantly shorter than that of AMC and GCV (4.5 ± 2.6 vs. 12.1 ± 7.4 vs. 17.4 ± 4.7, P < 0.05), respectively. In multivariate logistic regression analysis, LATD was associated with intramural origins (odds ratio: 0.711, confidence interval: 0.514−0.985, P = 0.040). ROC analysis revealed LATD of 7 ms as cut-off value. In computed tomography analysis, some patients who had thick fat tissue below the GCV, and an unusual GCV running pattern might be misdiagnosed as intramural origins. Conclusion: LATD ≤ 7 ms was associated with intramural origins, but with some anatomical limitations. [ABSTRACT FROM AUTHOR]

Our study aims to establish trends and frequencies of ventricular tachyarrhythmia (VTA) among patients with chronic coronary total occlusion (CCTO). We identified CCTO hospitalizations with and without VTA using the National Inpatient Sample. A total of 911,579 CCTO-related hospitalizations were identified, with 92,450 (10.1%) encounters associated with VTA. The CCTO-VTA cohort showed higher all-cause mortality (adjusted odds ratio [aOR] = 4.45, P < 0.001), longer hospital stays (6.8 vs 4.6 days; P < 0.001), and higher hospital charges ($117,382 vs $75,419; P < 0.001) compared to the CCTO non-VTA group. Rates and odds of cardiogenic shock (aOR = 4.19), venous thromboembolism (aOR = 2.09), respiratory failure (aOR = 2.85), and requirement of mechanical ventilation (aOR = 4.23) were higher in the CCTO-VTA group (P < 0.001). Over time, there was an increase in VTA (9.2% in 2010 to 12.1% in 2014) and all-cause mortality (7.5% in 2010 to 12.4% in 2014; P < 0.001). Trends in VTA among patients with CCTO increased by 4.8% for undergoing percutaneous coronary intervention and by 2.5% for undergoing both percutaneous coronary intervention and coronary artery bypass grafting (P < 0.001). Occurrence of VTA among CCTO patients is associated with worse outcomes and higher resource utilization. [ABSTRACT FROM AUTHOR]

According to current clinical guidelines, the risk of life-threatening ventricular tachyarrhythmias (VTAs) in patients with heart failure (HF) is determined by left ventricular ejection fraction (LVEF). The available clinical and experimental data indicate the imperfection of this one-factor approach, which specifies the need to search for new predictors of VTAs. In this prospective study, we performed a comparative analysis of surface electrocardiographic parameters in HF patients with LVEF ≤35% without syncope or sustained ventricular arrhythmias in history, who were implanted with cardioverter defibrillator as a primary prevention of sudden cardiac death. During the two-year follow-up, the primary endpoint (new-onset persistent VTA episode, or VTA/ventricular fibrillation that required electrotherapy) was recorded in 42 patients (25,5%). The secondary endpoint (an increase in LVEF by 5% or more of the initial level against the background of cardiac resynchronization therapy) was more often recorded in the group of patients without VTAs (41 (33%) vs 4 (9,5%), p=0,005). The studied cohort of patients was characterized by a left axis deviation (72%), LV hypertrophy signs (84%), impaired intra-atrial (P wave duration of 120 (101-120) ms) and intraventricular conduction (QRS duration of 140 (110-180) ms), ventricular electrical systole prolongation (QTcor — 465 (438-504) ms). Differences between the groups divided depending on reaching the primary endpoint in terms of the Cornell product, Cornell voltage index and ICEB, as well as the detection rate of complete left bundle branch block morphology had levels of significance close to critical (p=0,09; p=0,05; p=0,1; p=0,09, respectively). The multivariate predictive model included following factors: Cornell product, Tp-Te/ QRS, P wave duration (diagnostic efficiency of the model was 60%: sensitivity, 61,1%, specificity, 59,6%; p=0,007).

Left ventricular hypertrophy (LVH) refers to a complex rebuilding of the left ventricle that can gradually lead to serious complications—heart failure and life-threatening ventricular arrhythmias. LVH is defined as an increase in the size of the left ventricle (i.e., anatomically), therefore the basic diagnosis detecting the increase in the LV size is the domain of imaging methods such as echocardiography and cardiac magnetic resonance. However, to evaluate the functional status indicating the gradual deterioration of the left ventricular myocardium, additional methods are available approaching the complex process of hypertrophic remodeling. The novel molecular and genetic biomarkers provide insights on the underlying processes, representing a potential basis for targeted therapy. This review summarizes the spectrum of the main biomarkers employed in the LVH valuation.

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Despite the contemporary treatment of acute coronary syndromes, arrhythmic complications occurring prior to medical attendance remain significant, mandating in-depth understanding of the underlying mechanisms. Sympathetic activation has long been known to play a key role in the pathophysiology of ischemia-induced arrhythmias, but the regulating factors remain under investigation. Several lines of evidence implicate the endothelin system (a family of three isopeptides and two specific receptors) as an important modulator of sympathetic activation in the setting of acute coronary syndromes. Such interaction is present in the heart and in the adrenal medulla, whereas less is known on the effects of the endothelin system on the central autonomic network. This article summarizes the current state-of-the-art, placing emphasis on early-phase arrhythmogenesis, and highlights potential areas of future research.

The TBX5 gene encodes the T-box transcription factor 5 (Tbx5) involved in the regulation of developmental processes in both vertebrates and invertebrates. Mutations in this gene cause rare monogenic Holt–Oram syndrome (HOS) characterized by skeletal anomalies of the upper limbs, a congenital heart defect, and/or сardiac сonduction system diseases. Next generation sequencing (NGS) made it possible to detect a new nucleotide variant c.713G>C (p.Gly238Ala) in the TBX5 gene in a patient with a mild Holt–Oram syndrome phenotype (thoracic spine deformity (scoliosis) and scapula dysplasia and showing signs of mitral and triсuspid valve insufficiency with first- and second-degree regurgitation and atrial septal thinning) and life-threatening tachyarrhythmias that required a cardioverter-defibrillator implantation (CDI). The mutation is localized in the "hot spot" of the TBX5 gene. Evaluation of its pathogenicity by in silico analysis showed that the c.713G>C nucleotide substitution can lead to changes in the protein structure and/or its function. Non-sustained ventricular tachycardia/ventricular fibrillation, which is not characteristic of HOS, could have resulted from two additional rare substitutions (MAF < 0.01%): p.Val3634Asp, rs66785829 in the ANK2 gene and p.Arg1193Gln, rs41261344 in the SCN5A gene. Mutations in these genes affect the voltage-gated sodium channel functioning and cause hereditary arrhythmia. [ABSTRACT FROM AUTHOR]

Background: Coronavirus disease 2019 (COVID‐19) primarily causes lung infection, but recent studies have shown that cardiac involvement is associated with a worse prognosis. Objectives: We conducted a systematic review and meta‐analysis to examine the prevalence of cardiac arrhythmias detected by the electrocardiogram and their relationships with adverse outcomes in patients with COVID‐19. Methods: PubMed and Google were searched for studies that reported on cardiac arrhythmias and/or examined the relationship between arrhythmias and adverse outcomes. Results: Thirty studies with 12,713 participants were included in the systematic review, and 28 studies (n = 12,499) in the meta‐analysis. The mean age was 61.3 ± 16.8 years; 39.3% were female. In 25 studies with 7578 patients, the overall prevalence of cardiac arrhythmias was 10.3% (95% confidence interval [CI]: 8.4%–12.3%). The most common arrhythmias documented during hospitalization were supraventricular arrhythmias (6.2%, 95% CI: 4.4%–8.1%) followed by ventricular arrhythmias (2.5%, 95% CI: 1.8%–3.1%). The incidence of cardiac arrhythmias was higher among critically ill patients (relative risk [RR]: 12.1, 95% CI: 8.5–17.3) and among non‐survivors (RR: 3.8, 95%, CI: 1.7–8.7). Eight studies reported changes in the QT interval. The prevalence of QTc > 500 ms was 12.3% (95% CI: 6.9%–17.8%). ST‐segment deviation was reported in eight studies, with a pooled estimate of 8.7% (95% CI: 7.3% to 10.0%). Conclusion: Our meta‐analysis showed that QTc prolongation, ST‐segment deviation, and various other cardiac arrhythmias were observed in patients hospitalized with COVID‐19. The presence of cardiac arrhythmias was associated with a worse prognosis. [ABSTRACT FROM AUTHOR]

Abstract Objectives The study sought to assess the impact of statin therapy on survival in patients presenting with ventricular tachyarrhythmias. Background Data regarding the outcome of patients with statin therapy presenting with ventricular tachyarrhythmias is limited. Methods A large retrospective registry was used including all consecutive patients presenting with ventricular tachycardia (VT) or fibrillation (VF) from 2002 to 2016. Patients with statin were compared to patients without statin therapy (non-statin). The primary prognostic endpoint was long-term all-cause death at 3 years. Uni- and multivariable Cox regression analyses were applied in propensity-score matched cohorts. Results A total of 424 matched patients was included. The rates of VT and VF were similar in both groups (VT: statin 71% vs. non-statin 68%; VF: statin 29% vs. 32%; p = 0.460). Statin therapy was associated with lower all-cause mortality at long-term follow-up (mortality rates 16% versus 33%; log rank, p = 0.001; HR = 0.438; 95% CI 0.290–0.663; p = 0.001), irrespective of the underlying type of ventricular tachyarrhythmia (VT/VF), left ventricular ejection fraction (LVEF) > 35%, presence of an activated implantable cardioverter defibrillator (ICD), cardiogenic shock or cardiopulmonary resuscitation (CPR). Conclusion Statin therapy is independently associated with lower long-term mortality in patients presenting with ventricular tachyarrhythmias on admission. Trial registration Clinicaltrials.gov, NCT02982473, 11/29/2016, Retrospectively registered.

Non-compaction cardiomyopathy (NCM) is a rare heart disease characterized by a two-layered ventricular wall, comprising a thinner compact epicardial layer and an inner non-compacted layer. However, only structural and morphological data without a thorough clinical assessment does not determine the NCM (regardless of the diagnostic criterion used).Aim. To study the NCM-related genes, phenotypic and genetic correlations, predictors of life-threatening ventricular tachyarrhythmias (VTA) and adverse clinical outcomes.Material and methods. Of 93 individuals with identified morphological criteria of NCM (median follow-up, 5 years), the study included 60 unrelated patients (38,5±13,8 years of age; men, 33 (55%); left ventricular ejection fraction (LVEF), 42,1±12,9%) with clinical verification of NCM (>1 obligate phenotypic trait). Adverse cardiovascular events were taken as the composite end point: life-threatening VTA, death, heart transplantation.Results. Pathogenic (or probably pathogenic) mutations were detected in 33 (55%) patients with NCM. The most common variants (57,9%) were identified in the sarcomere protein genes (TTN, MYBPC3, MYH7); digenic mutations were found in 21,6% of patients. Digenic mutations were associated with low LVEF and the highest risk of systolic dysfunction (OR, 38; 95% CI, 4,74-305; p=0,0001). Multivariate regression provided a predictive model (R=0,90; R2=0,81; F (5,41) =34,8; p

Aim. To study the changes in N-terminal pro-brain natriuretic peptide (NT-proBNP) and growth stimulation gene-2 (sST2) to predict isolated episodes of ventricular tachyarrhythmias (VTA) and electrical storm (ES) in patients with systolic heart failure and implanted cardioverter-defibrillators, cardiac resynchronization therapy (CRT) defibrillators, as well as cardiac contractility modulation (CCM) devices.Material and methods. The study included 69 patients (mean, 59; women, 10; mean age, 59±13 years) with class I-III systolic HF and ischemic (n=36) or nonischemic (n=33) cardiomyopathy. The survey was carried out at baseline, as well as 1, 3, 6 and 12 months after device implantation. This included data collection, physical examination, determination of NT-proBNP and sST2, 6-minute walk test, electrocardiography (ECG), 24-hour Holter monitoring, echocardiography, assessment of device performance. Predictors of isolated VTA and ES were identified using ROC and multivariate analyzes.Results. According to the follow-up (median, 28 months) results, 3 groups of patients were formed: group 1 — without VTA (n=45); group 2 — isolated VTA (n=15); group 3 — ES (n=9). According to multivariate analysis, predictors of isolated VTA were as follows: 1) baseline NT-proBNP >3200 pg/ml; 2) minimum NTproBNP >1100 pg/ml during 12-month follow-up; 3) sST2 >26 ng/ml 3 months after device implantation; 4) presence of old myocardial infarction; 5) no echocardiographic signs of response to CRT or CCM therapy. There were following predictors of ES: 1) left ventricular end-systolic dimension >7,0 cm; 2) presence of VTA runs according to 24-hour Holter monitoring; 3) no echocardiographic signs of response to CRT or CCM therapy.Conclusion. The results obtained indicate that NT-proBNP and sST2 assessment in patients with systolic heart failure is promising for predicting isolated VTA, but not ES. Cardiac reverse remodeling as a result of effective CRT or CCM therapy is associated with a significant risk reduction for isolated VTA and ES.

Left stellate or right stellate ganglion stimulation (LGSG or RSGS, respectively) is associated with ventricular tachyarrhythmias; however, the electrophysiological mechanisms remain unclear. We assessed 1) regional dispersion of myocardial repolarization during RSGS and LSGS and 2) regional electrophysiological mechanisms underlying T-wave changes, including T-peak to T-end (Tp-e) interval, which are associated with ventricular tachyarrhythmia/ventricular fibrillation. In 10 pigs, a 56-electrode sock was placed around the heart, and both stellate ganglia were exposed. Unipolar electrograms, to asses activation recovery interval (ARI) and repolarization time (RT), and 12-lead ECG were recorded before and during RSGS and LSGS. Both LSGS and RSGS increased dispersion of repolarization; with LSGS, the greatest regional dispersion occurred on the left ventricular (LV) anterior wall and LV apex, whereas with RSGS, the greatest regional dispersion occurred on the right ventricular posterior wall. Baseline, LSGS, and RSGS dispersion correlated with Tp-e. The increase in RT dispersion, which was due to an increase in ARI dispersion, correlated with the increase in Tp-e intervals (R(2) = 0.92 LSGS; and R(2) = 0.96 RSGS). During LSGS, the ARIs and RTs on the lateral and posterior walls were shorter than the anterior LV wall (P < 0.01) and on the apex versus base (P < 0.05), explaining the T-wave vector shift posteriorly/inferiorly. RSGS caused greater ARI and RT shortening on anterior versus lateral or posterior walls (P < 0.01) and on base versus apex (P < 0.05), explaining the T-wave vector shift anteriorly/superiorly. LSGS and RSGS cause differential effects on regional myocardial repolarization, explaining the ECG T-wave morphology. Sympathetic stimulation, in line with its proarrhythmic effects, increases Tp-e interval, which correlates with increases in myocardial dispersion of repolarization.

Background: Despite a few studies evaluating the prognostic impact of coronary chronic total occlusion (CTO) in implantable cardioverter defibrillator (ICD) recipients, the impact of CTO on different types of recurrences of ventricular tachyarrhythmias, as well as their predictors has not yet been investigated in CTO patients. Methods: A large retrospective registry was used including all consecutive patients with ventricular tachyarrhythmias undergoing coronary angiography at index from 2002 to 2016. Only ICD recipients with CTO were compared to patients without (non-CTO). Kaplan–Meier and Cox regression analyses were applied for the primary end point of first recurrence of ventricular tachyarrhythmias at 5 years. Secondary end points comprised of the different types of recurrences, first appropriate ICD therapy and all-cause mortality at 5 years. Results: From a total of 422 consecutive ICD recipients with ventricular tachyarrhythmias at index, at least one CTO was present in 25%. CTO was associated with the primary end point of first recurrence of ventricular tachyarrhythmias at 5 years (55% vs. 39%; log rank p = 0.001; HR = 1.665; 95% CI 1.221–2.271; p = 0.001), as well as increased risk of first appropriate ICD therapy (40% vs. 31%; log rank p = 0.039; HR = 1.454; 95% CI 1.016–2.079; p = 0.041) and all-cause mortality at 5 years (26% vs. 16%; log rank p = 0.011; HR = 1.797; 95% CI 1.133–2.850; p = 0.013). Less developed collaterals (i.e., either ipsi- or contralateral compared to bilateral) and a J-CTO score ≥ 3 were strongest predictors of recurrences in CTO patients at 5 years. Conclusion: A coronary CTO even in the presence of less developed collaterals and more complex CTO category is associated with increasing risk of recurrent ventricular tachyarrhythmias at 5 years in consecutive ICD recipients. [ABSTRACT FROM AUTHOR]

Background: Patients with post‐infarct cardiomyopathy and ventricular arrhythmias (VT) necessitating implantable cardioverter defibrillators (ICD) are at risk of recurrent shocks with increased morbidity. Methods: A comprehensive search of electronic databases for all randomized clinical trials that evaluated the role of catheter ablation as a preventive strategy at the time of secondary prevention ICD implantation was performed. We calculated hazard ratios (HR) and 95% confidence intervals (CI) using random‐effects model. Results: Four trials were identified with a total of 505 patients (average age 66.4 ± 9.0 years; 87.7% were male). Preventive ablation was associated with a significant reduction in appropriate device therapies (shocks and/or anti‐tachycardia therapy) (HR = 0.62; 95% CI = 0.46‐0.82; P <.01), sustained VT (HR = 0.74; 95% CI = 0.55‐0.99; P =.04) compared to control. There were no differences in inappropriate device shocks (HR = 0.80; 95% CI = 0.38‐1.71), all‐cause death (HR = 0.93; 95% CI = 0.53‐1.64), cardiac death (HR = 0.63; 95% CI = 0.29‐1.36), arrhythmic death (HR = 0.26; 95% CI = 0.05‐1.31), or cardiac hospitalization (HR = 0.79; 95% CI = 0.57‐1.11) between strategies. Preventive ablation was associated with improved SF‐36 physical component (mean difference = 2.81; 95% CI‐0.53‐5.10; P =.02), but not the mental component (mean difference = 1.30; 95% CI = ‐2.06‐4.66). Conclusion: Among patients with post‐infarct cardiomyopathy and VT, preventive catheter ablation at the time of ICD implantation is associated with a significant reduction of appropriate ICD therapy and sustained VT, and improvement in the physical component of quality‐of‐life, but no reduction in mortality. [ABSTRACT FROM AUTHOR]

Abstract Objectives The study sought to assess the prognostic impact of type 2 diabetes in patients presenting with ventricular tachyarrhythmias on admission. Background Data regarding the prognostic outcome of diabetics presenting with ventricular tachyarrhythmias is limited. Methods A large retrospective registry was used including all consecutive patients presenting with ventricular tachycardia (VT) and fibrillation (VF) on admission from 2002 to 2016. Patients with type 2 diabetes (diabetics) were compared to non-diabetics applying multivariable Cox regression models and propensity-score matching for evaluation of the primary prognostic endpoint of long-term all-cause mortality at 2 years. Secondary prognostic endpoints were cardiac death at 24 h, in-hospital death at index, all-cause mortality at 30 days, all-cause mortality in patients surviving index hospitalization at 2 years (i.e. “after discharge”) and rehospitalization due to recurrent ventricular tachyarrhythmias at 2 years. Results In 2411 unmatched high-risk patients with ventricular tachyarrhythmias, diabetes was present in 25% compared to non-diabetics (75%). Rates of VT (57% vs. 56%) and VF (43% vs. 44%) were comparable in both groups. Multivariable Cox regression models revealed diabetics associated with the primary endpoint of long-term all-cause mortality at 2 years (HR = 1.513; p = 0.001), which was still proven after propensity score matching (46% vs. 33%, log rank p = 0.001; HR = 1.525; p = 0.001). The rates of secondary endpoints were higher for in-hospital death at index, all-cause mortality at 30 days, as well as after discharge, but not for cardiac death at 24 h or rehospitalization due to recurrent ventricular tachyarrhythmias. Conclusion Presence of type 2 diabetes is independently associated with an increase of all-cause mortality in patients presenting with ventricular tachyarrhythmias on admission.

• The reference values for ambulatory-based frequency domain T wave alternans (FD-TWA) were established. • Ambulatory-based FD-TWA values were mostly influenced by heart rate. • Also, ambulatory-based FD-TWA values related to age. • Maximum FD-TWA was observed mostly in the Z lead regardless of the age group and position. Conventional frequency domain T wave alternans (FD-TWA) is a noninvasive risk stratification marker for identifying arrhythmic sudden cardiac death, but the conventional FD-TWA device that was considered the gold standard device has been discontinued commercially. Recently, a newly developed ambulatory electrocardiogram (AECG) device that can detect FD-TWA continuously for 24 hours is available in clinical settings. However, information on the normal values using the novel AECG-based frequency domain TWA (FD-TWA) is lacking. FD-TWA for AECG was examined in 312 subjects without heart disease (Sb-wHD) (range 20-89 years, 146 men) and 30 heart disease patients (HD-P) (mean age 57±17 years, 24 men). The maximum FD-TWA amplitude over 24 hours was measured with manual editing. The upper limit of local noise levels for measurement of FD-TWA was set to both <10 μV and <20 μV (acceptable noise level <10 μV and <20 μV). The reference values (95th percentiles) of FD-TWA in Sb-wHD were 19.9 μV for the acceptable noise level <10 μV and 23.6 μV for the acceptable noise level <20 μV. The 75th percentile of FD-TWA amplitude in HD-P was 19.5 µV at an acceptable noise level <10 µV and 21.5 µV at an acceptable noise level <20 µV. FD-TWA amplitude without heart disease was significantly affected by heart rate when the maximum FD-TWA was measured (β = 0.274 p < 0.001 for the acceptable noise level <10 μV; β = 0.263, p < 0.001 for the acceptable noise level <20 μV) and age (β = 0.204, p = 0.004 for the acceptable noise level <10 μV; β = 0.149, p = 0.034 for the acceptable noise level <20 μV). In the present study, the reference values for a novel FD-TWA in Sb-wHD and the distribution of TWA values in HD-P were established. In future research, the cut-off values of FD-TWA in HD-P will need to be examined. [ABSTRACT FROM AUTHOR]

Aims: The primary aim of the VIP‐HF study was to examine the incidence of sustained ventricular tachyarrhythmias (VTs) in heart failure (HF) with mid‐range (HFmrEF) or preserved ejection fraction (HFpEF). Secondary aims were to examine the incidence of non‐sustained VTs, bradyarrhythmias, HF hospitalizations and mortality. Methods and results: This was an investigator‐initiated, prospective, multicentre, observational study of patients with HF and left ventricular ejection fraction (LVEF) >40%. Patients underwent extensive phenotyping, after which an implantable loop recorder was implanted. We enrolled 113 of the planned 250 patients [mean age 73 ± 8 years, 51% women, New York Heart Association class II/III 54%/46%, median N‐terminal pro B‐type natriuretic peptide 1367 (710–2452) pg/mL and mean LVEF 54 ± 6%; 75% had LVEF >50%]. Eighteen percent had non‐sustained VTs and 37% had atrial fibrillation on Holter monitoring. During a median follow‐up of 657 (219–748) days, the primary endpoint of sustained VT was observed in one patient. The incidence of the primary endpoint was 0.6 (95% confidence interval 0.2–3.5) per 100 person‐years. The incidence of the secondary endpoint of non‐sustained VT was 11.5 (7.1–18.7) per 100 person‐years. Five patients developed bradyarrhythmias [3.2 (1.4–7.5) per 100 person‐years], three were implanted with a pacemaker. In total, 23 patients (20%) were hospitalized for HF [16.3 (10.9–24.4) per 100 person‐years]. Fourteen patients (12%) died [8.7 (5.2–14.7) per 100 person‐years]; 10 due to cardiovascular causes, and four sudden deaths, one with implantable loop recorder‐confirmed bradyarrhythmias as terminal event, three others undetermined. Conclusion: Despite the lower than expected number of included patients, the incidence of sustained VTs in HFmrEF/HFpEF was low. Clinically relevant bradyarrhythmias were more often observed than expected. [ABSTRACT FROM AUTHOR]

Objective: The objective of the study was to compare the incidence of post STEMI ventricular arrhythmias among patients with versus without LV dysfunction. Methodology: This prospective Cohort study was conducted in the department of cardiology of a tertiary care hospital, Isra University Hospital, Hyderabad over a period of eleven months from 1st September 2019 to 31st July 2020 and recruited a total of 95 patients with STEMI. Baseline data (age, gender, social class, and marital status) and clinical data (basal metabolic rate, systolic and diastolic blood pressure, random blood sugar, and LVSD) were recorded in a pre-structured questionnaire and analyzed using Statistical Package for the Social Sciences (SPSS) version 21 to see the comparative incidence of ventricular arrhythmias by applying chi-square test where applicable. Results: Out of total 95 STEMI patients, 53 patients had left ventricular systolic dysfunction (55.7%). The overall incidence of ventricular arrhythmias was 23.1% and it was significantly higher in patients with LVSD as compared to those with normal LV function, 36.3% and 72.7% respectively (p = 0.001). Conclusion: Our study shows that overall burden of ventricular tachyarrhythmias is two times higher in patients with left ventricular systolic dysfunction as compared to normal left ventricular systolic function. [ABSTRACT FROM AUTHOR]

Background: The study sought to assess the prognostic impact of potassium levels (K) in patients with ventricular tachyarrhythmias. Methods: A large retrospective registry was used including all consecutive patients presenting with ventricular tachyarrhythmias on admission from 2002 to 2016. Patients with hypokalemia (i.e., K < 3.3 mmol/L), normokalemia (i.e., K 3.3–4.5 mmol/L), and hyperkalemia (i.e., K > 4.5 mmol/L) were compared applying multi-variable Cox regression models and propensity-score matching for evaluation of the primary endpoint of all-cause mortality at 3 years. Secondary endpoints were early cardiac death at 24 h, in-hospital death, death at 30 days, as well as the composite endpoint of early cardiac death at 24 h, recurrences of ventricular tachyarrhythmias, and appropriate ICD therapies at 3 years. Results: In 1990 consecutive patients with ventricular tachyarrhythmias, 63% of the patients presented with normokalemia, 30% with hyperkalemia, and 7% with hypokalemia. After propensity matching, both hypokalemic (HR = 1.545; 95% CI 0.970–2.459; p = 0.067) and hyperkalemic patients (HR = 1.371; 95% CI 1.094–1.718; p = 0.006) were associated with the primary endpoint of all-cause mortality at 3 years compared to normokalemic patients. Hyperkalemia was associated with even worse prognosis directly compared to hypokalemia (HR = 1.496; 95% CI 1.002–2.233; p = 0.049). In contrast, potassium measurements were not associated with the composite endpoint at 3 years. Conclusion: In patients presenting with ventricular tachyarrhythmias, normokalemia was associated with best short- and long-term survival, whereas hyperkalemia and hypokalemia were associated with increased mortality at 30 days and at 3 years. [ABSTRACT FROM AUTHOR]

Aims: Inappropriate shocks (IAS) remain a challenge for patients and physicians after implantation of the subcutaneous implantable cardioverter-defibrillator (S-ICD). The aims were to assess and characterize different patterns of IAS.Methods and Results: Two hundred and thirty-nine patients were implanted with an S-ICD between 2010 and 2018 for primary and secondary prevention. Follow-up data of at least 6 months were analysed. During a mean follow-up of 34.9 ± 16.0 months, a total of 73 shocks occurred in 38 patients (6%). Forty-three (59%) shocks were considered appropriate due to ventricular tachycardia/ventricular fibrillation, while 30 (41%) were inappropriate and occurred in 19 patients (8%). Myopotentials/noise was the most frequent cause of inappropriate shocks (n = 8), followed by T-wave oversensing (n = 6) and undersensing of the QRS, resulting in adaptation of the automatic gain control and inappropriate shock (n = 5). Seventy-four percent of all IAS occurred on the primary vector, while no IAS occurred on the alternate vector. In seven of eight patients (88%), IAS related to myopotentials have occurred on the primary sensing vector. Multivariate analysis identified taller patients, primary sensing vector and first-generation S-ICD device as predictors for IAS. SMART pass effectively reduced the occurrence of IAS in the second-generation S-ICD system.Conclusion: Inappropriate therapies are less frequently observed on the alternate vector. The primary vector seems to be unfavourable with regard to oversensing caused by myopotentials. Inappropriate shocks were associated with an increased rate of rehospitalization but not mortality. These observations have implications for the prevention of inappropriate S-ICD shocks. [ABSTRACT FROM AUTHOR]

Background: Only few data evaluating the prognostic impact of blood-derived potassium levels (K) on arrhythmic endpoints in patients with implantable cardioverter-defibrillators (ICD) is available. Therefore, this study evaluates the prognostic impact of potassium levels on recurrences of ventricular tachyarrhythmias in consecutive ICD recipients. Methods: A large retrospective registry was used including all consecutive patients presenting with ventricular tachyarrhythmias on admission from 2002 to 2016 at one institution. Patients were divided into three subgroups: hypokalemia (i.e., K < 3.3 mmol/L), normokalemia (i.e., K 3.3 - 4.5 mmol/L), and hyperkalemia (i.e., K > 4.5 mmol/L). Kaplan-Meier and Cox regression analyses were applied for the evaluation of the primary endpoint of first recurrences of ventricular tachyarrhythmias at one year. Secondary endpoints comprised of first appropriate ICD therapy, first cardiac rehospitalization, and all-cause mortality at one year. Results: Five hundred and thirty ICD recipients with a median potassium level of 4.23 mmol/L were included (67%: normokalemia, 27%: hyperkalemia, and 6%: hypokalemia). Whereas hyperkalemia was not associated with increasing risk of recurrent ventricular tachyarrhythmias, hypokalemia was associated with decreasing freedom from recurrent ventricular tachyarrhythmias (HR = 2.135; 95% CI 1.158 - 3.937; p = 0.015), even after multivariable adjustment (HR = 2.577; 95% CI 1.236 - 5.372; p = 0.012). Higher risk of recurrences was especially attributed to higher rates of electrical storm in the presence of hypokalemia (15% vs. 3 - 4%). Negative impact of hypokalemia was mainly attributed to secondary preventive ICD (HR = 2.637; 95% CI 1.325 - 5.248; p = 0.006). Moreover, hypokalemia was associated with increasing risk of appropriate ICD therapies (HR = 1.920; 95% CI 0.912 - 4.042; statistical trend: p = 0.086), which was still demonstrated after multivariable adjustment. In contrast, risk of first cardiac rehospitalization and all-cause mortality were not affected by potassium levels. Conclusions: In consecutive ICD recipients with ventricular tachyarrhythmias at index, hypokalemia - but not hyperkalemia - was associated with increasing risk of recurrent ventricular tachyarrhythmias and appropriate ICD therapies. [ABSTRACT FROM AUTHOR]

Aims: To explore the association between resting heart rate (RHR) and ventricular tachyarrhythmias (VTA) events among patients who were enrolled in MADIT-RIT.Methods and Results: Multivariate Cox proportional hazards regression modelling was employed to evaluate the association between baseline RHR [dichotomized at the lower quartile (≤63 b.p.m.) and further assessed as a continuous measure] and the risk for any VTA, fast VTA (>200 b.p.m.), and appropriate implantable cardioverter-defibrillator (ICD) therapy, among 1500 patients who were enrolled in MADIT-RIT. Kaplan-Meier survival analysis showed that at 2 years of follow-up the rate of any VTA was significantly lower among patients with low baseline RHR (≤63 b.p.m.) as compared with faster RHR (11% vs. 19%, respectively; P = 0.001 for the overall difference during follow-up). Similar results were shown for the association with the rate of fast VTA (8% vs. 14%, respectively; P = 0.016), and appropriate ICD therapy (10% vs. 18%, respectively; P = 0.004). Multivariate analysis, after adjustment for medical therapy, showed that low baseline RHR was associated with a significant 45% (P = 0.002) reduction in the VTA risk as compared with faster baseline RHRs. When assessed as a continuous measure, each 10 b.p.m. decrement in RHR was associated with a corresponding 13% (P = 0.014) reduction in the VTA risk.Conclusion: In MADIT-RIT, low RHR was independently associated with a lower risk for life-threatening arrhythmic events. These findings suggest a possible role for RHR for improved selection of candidates for ICD therapy. [ABSTRACT FROM AUTHOR]

Ischemic cardiomyopathy often presents with advanced heart failure necessitating an intensive multidisciplinary approach to management. These patients constitute a very difficult population presenting with angina and ventricular tachyarrhythmias sometimes presenting as sudden cardiac death. In those patients presenting with spontaneous ventricular tachyarrhythmias, treatment with automated intracardiac defibrillator implantation has a significant mortality benefit. In patients with significant left ventricular (LV) dilatation and a left ventricular ejection fraction ≤ 30%, guidelines state that device implantation should be preceded by programmed electrical stimulation, which demonstrates inducible ventricular tachyarrhythmia. The treatment options for patients with moderate LV dilatation and ejection fraction ≥ 30% is individualized. Devices have their associated problems. Radiofrequency ablation has mixed results. Surgical cryoablation when performed concomitantly with surgical ventricular restoration has shown promising results. But, this option remains isolated to patients eligible for surgical ventricular restoration. Programmed electrical stimulation for inducibility of ventricular tachyarrhythmias in these patients also has a questionable role. The need for programmed electrical stimulation prior to cryoablation also seems highly individualized. In this review, we discuss the mechanisms of ischemic ventricular tachyarrhythmias and treatment options in heart failure. The mechanisms of ventricular arrhythmogenesis in ischemic cardiomyopathy help in formulating novel technical modifications for cryoablation when performed concomitantly with surgical ventricular restoration. [ABSTRACT FROM AUTHOR]

Several studies have indicated that early repolarization (ER) is a risk factor for ventricular tachyarrhythmias (VTAs) in acute myocardial infarction (AMI) patients. The prognostic values of ER detail characteristics except J-point morphology, and inferior leads ER location for VTAs are still unclear. We searched PubMed, Embase, and the Cochrane Library for eligible studies up to March 4, 2019. Studies to investigate the relationship between ER and the incidence of VTAs in AMI patients were extracted. A total of 10 studies with 2,672 participants were included in the analysis. ER significantly predicted the incidence of VTAs (odds ratio [OR] 3.62, 95% confidence intervals [CI] 2.77–4.73), regardless of the type of AMI. The presence of ER before AMI (OR 5.58, 95% CI 3.41 to 9.12) and after AMI (OR 3.02, 95% CI 2.19–4.15) increased the risk of VTAs. The prognostic value of ER for VTAs in the long follow-up (≥30 days) (OR 2.39, 95% CI 1.59–3.59) fell by half compared to the short follow-up duration (<30 days) (OR 4.97, 95% CI 3.48–7.09). Patients with ER displayed a higher risk of developing ventricular fibrillation (VF) (OR 6.94, 95% CI 3.87–12.43) than those without ER. However, neither J-point elevation with OR = 2.48 nor lateral leads' ER location with OR = 3.83 remarkably increased the risk of VTAs in patients with AMI. ER is significantly associated with increasing risk of VTAs, particularly VF, in AMI patients. This relationship is weaker in the 30-day follow-up and is not reinforced by J-point elevation and lateral leads' ER location. [ABSTRACT FROM AUTHOR]

Cardiac metaiodobenzylguanidine (MIBG) imaging provides prognostic information in patients with heart failure (HF). Recent studies showed that the highest rate of ventricular tachyarrhythmias (VTs) is seen in HF patients with an intermediate decrease in MIBG uptake, rather than in those with the lowest values. However, prolonged QRS duration (QRSd) has been shown to be associated with VTs in HF patients. This study assessed the prognostic value of the combination of an intermediate decrease in MIBG uptake and prolonged QRSd for predicting VTs in patients with implantable cardioverter defibrillators (ICDs) in relation to the presence of heart failure (HF). A total of 196 outpatients with ICDs (age: 64 ± 14 years, male: 81%, left ventricular ejection fraction [LVEF]: 49% ± 16%) were prospectively enrolled; 135 had HF (NYHA class: 2.0 ± 0.6). At entry, cardiac MIBG imaging was performed, and QRSd was measured on standard 12‑lead electrocardiography. An intermediate decrease in the heart-to-mediastinum ratio on the delayed planar image (ID-H/M) was defined as 1.40–1.89. During the 3.3 ± 2.2-year follow-up, 59 patients had appropriate ICD discharges (ATx) for VTs. On multivariate Cox analysis, ID-H/M and prolonged QRSd (≥147 ms) were significantly and independently associated with ATx. In both patients with and without HF, ATx were significantly more frequent in patients with ID-H/M and/or prolonged QRSd than in those with neither (with HF: 40% vs. 14%, p = 0.020; without HF: 43% vs. 10%, p = 0.0028). The combination of ID-H/M and prolonged QRSd provided more prognostic information for predicting VTs in ICD patients, with and without HF. • Combination of MIBG imaging and QRS duration could predict appropriate ICD therapy. • Highest rate of the therapy was seen in the intermediate decrease in MIBG uptake. • The therapy was more frequent in patients with than without prolonged QRS duration. • This combination was useful even in patients with and without heart failure. [ABSTRACT FROM AUTHOR]

Aim: In acute phase of acute coronary syndrome (ACS), ventricular tachycardia (VT) and/or ventricular fibrillation (VF) leading to resuscitation are not considered to be associated with increased long-term sudden cardiac death (SCD) because the cause - acute ischemia - is believed to be reversible.Aim of this study was to investigate whether ventricular arrhythmias leading to sudden cardiac arrest during ACS associate with the risk of incident SCD in patients with normal or mildly impaired left ventricular ejection fraction (LVEF)., Methods: This study is based on a retrospective analysis of all 8,062 consecutive ACS patients undergoing coronary angiography with baseline LVEF ≥40% between 2007-2018 (follow-up until December 31st, 2021). The primary outcome was SCD equivalent life-threatening ventricular arrhythmias (LTVA) composing of true SCDs, aborted SCDs by successful resuscitation or appropriate ICD therapy. The risk of sudden LTVA was estimated with multivariate subdistribution hazard model using other deaths as competing events., Results: Two-hundred and thirteen (n=211, 2.6%) patients suffered acute phase VF/VT leading to resuscitation and survived to discharge and most happened before angiography (80.6%, N=170) and were VF (92.9%, N=196). During a median follow-up of 7.6 years, 3.9% (N=316) of all the patients had LTVA (10.0% in VF/VT group vs 3.8% in other patients). VF/VTs during ACS associated with an increased risk for future SCD (HR 3.07; 95% CI 1.94-4.85, p<0.001). Most LTVAs occurred in patients without ICDs., Conclusions: VF/VT in ACS associates with remarkably high long-term risk for SCD in patients with LVEF ≥40%., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)

QT interval prolongation is common in patients hospitalized with Takotsubo syndrome (TTS), however, only a minority experience ventricular tachyarrhythmias. Our aim was to characterize the electromechanical window (EMW) in patients with TTS and to evaluate its association with ventricular tachyarrhythmias. We preformed aretrospective analysis of 84 patients hospitalized with TTS in the Tel-Aviv Medical Center between 2013 and 2022. All patients underwent a comprehensive echocardiographic evaluation and the EMW was calculated by subtracting the QT interval from the QRS onset to the aortic valve closure obtained from a continuous-wave Doppler for the same beat. Of the 84 patients with TTS, 74 (88%) were female and the mean age was 70 ± 11 years. The mean left ventricular ejection fraction was 42 ± 8%. The EMW was negative in 81 patients (96%), and the mean EMW was -69 ± 50 ms. Ventricular tachyarrhythmias occurred in 7 patients (8%). The EMW of patients who experienced ventricular tachyarrhythmias was more negative than patients who did not (-133 ± 23 ms vs -63 ± 48 ms, p = 0.001). In the univariate analysis, EMW and QT were associated with ventricular tachyarrhythmias (univariate odds ratio [OR] EMW  1.03, 95% confidence interval [CI] 1.01 to 1.05, p = 0.003 and univariate OR QTc  1.02, 95% CI 1.01 to 1.03, p = 0.02); however, only EMW remained significant in the multivariate analysis (OR EMW  1.03 95% CI 1.03 to 1.05, p = 0.023). EMW was more effective than corrected QT interval in identifying patients who had ventricular tachyarrhythmias (AUC EMW : 0.89, 95% CI 0.82 to 0.97 vs AUC QTc  0.77, 95% CI 0.61 to 0.93, p = 0.02), and a cut-off value of -108 ms was predictive of ventricular tachyarrhythmias with a sensitivity of 86% and a specificity of 79%. In conclusion, EMW is negative in patients with TTS and is associated with increased risk for ventricular tachyarrhythmias. The role of EMW in the risk stratification of patients with TTS warrants further investigation., Competing Interests: Declaration of Competing Interest The authors have no competing interest to declare., (Copyright © 2023 Elsevier Inc. All rights reserved.)