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Background: The utility of long-term intermittent heart rhythm monitoring after atrial fibrillation (AF) ablation remains undear. Therefore, we compared the efficacy and usability of long-term intermittent (AliveCor Kardia (R) (ACK)) versus short continuous (Hotter) heart rhythm monitoring for the detection of AF recurrences after AF ablation and evaluated ACK accuracy to detect AF.Methods: Patients were provided with Hotter (for >= 24 h) simultaneously with an ACK (4 weeks) used three times a day and in case of symptoms. The primary endpoint was the difference in proportion of patients diagnosed with recurrent AF by ACK as compared to Holier monitoring. Secondary endpoints were the usability (System Usability Scale and a four-item questionnaire) of ACK and Holler monitoring; and the accuracy of the ACK algorithm for AF detection.Results: Out of 126 post-ablation patients, 115 (91.3%; 35 females, median age 64.0 [58.0-68.0] years) transmitted overall 7838 ACK ECG recordings. ACK and Holler monitoring detected 29 (252%) and 17 (14.8%) patients with AF recurrences, respectively (p < 0.001). More than 2 weeks of ACK monitoring did not have additional diagnostic yield for detection of AF recurrences. Patients graded ACK higher than Hotter monitoring and found ACK more convenient in daily usage than Holler (p < 0.001). Sensitivity and specificity of ACK for AF detection were 95.3% and 97.5%, respectively.Conclusions: Long-term intermittent monitoring by ACK more effectively detects AF recurrences after AF ablation and has a higher patients' usability than short continuous Holter monitoring. ACK showed a high accuracy to detect AF. (C) 2021 Elsevier B.V. All rights reserved.

Background Up to two-thirds of patients with obstructive coronary artery disease (CAD) have silent ischemia (SI), which predicts an adverse prognosis and can be a treatment target in obstructive CAD. Over 50% of women with ischemia and no obstructive CAD have coronary microvascular dysfunction (CMD), which is associated with adverse cardiovascular outcomes. We aimed to investigate the prevalence of SI in CMD in order to consider it as a potential treatment target. Methods 36 women with CMD by coronary reactivity testing and 16 age matched reference subjects underwent 24-h 12-lead ambulatory ECG monitoring (Mortara Instruments) after anti-ischemia medication withdrawal. Ambulatory ECG recordings were reviewed by two-physician consensus masked to subject status for SI measured by evidence of ≥1 minute horizontal or downsloping ST segment depression ≥1.0 mm, measured 80 ms from the J point. Results Demographics, resting heart rate, and systolic blood pressure were similar between CMD and reference subjects. Thirty-nine percent of CMD women had a total of 26 SI episodes vs. 0 episodes in the reference group (p = 0.002). Among these women 13/14 (93%) had SI, and few episodes (3/26, 12%) were symptomatic. Mean HR at the onset of SI was 96 ± 13 bpm and increased to 117 ± 16 bpm during the ischemic episodes. 87% reported symptoms that were not associated with ST depressions. Conclusions Ambulatory ischemia is prevalent in women with CMD, with a majority being SI, while most reported symptoms were not accompanied by ambulatory ischemia. Clinical trials evaluating anti-ischemic medications should be considered in the CMD population.

Objective The use of implantable cardiac monitors (ICM) is highly useful in syncope workup. Latest-generation devices can detect asymptomatic episodes of atrial fibrillation. The main objective of this study was to determine the incidence of subclinical atrial fibrillation (AF) detected in a patient population undergoing prolonged electrocardiographic monitoring with an ICM for the etiological workup of syncope. Methods Prospective observational study carried out in a tertiary hospital from April 2014 to October 2019. All consecutive adult patients monitored with a latest-generation ICM for syncope with no prior history of AF were included in the analysis. Results Of a total of 509 ICMs implanted during the study period, 208 patients fulfilled the inclusion criteria. 42 patients (20.2%) were found to have AF on ICM. The incidence of AF was 11.7 cases per 100 person-years (95% CI: 8.7–15.9 per 100 person-years). The median burden of AF was 0.2% (IQR 0–0.8%). Age, the presence of hypertension, chronic kidney disease, the size of the septum and left atrium on electrocardiogram and the presence of broad QRS on baseline electrocardiogram were predictors for the appearance of AF in the univariate analysis. Conclusion The incidental finding of atrial fibrillation in patients with syncope monitored with ICM is common. The burden of AF is low, and it is generally subclinical. These findings create added value for the use of ICM in the workup for syncope, although further studies are needed to determine the clinical benefit of documenting subclinical AF.

Wrist-worn heart rate (HR) monitors are increasingly popular. A paucity of data exists on their accuracy in atrial fibrillation (AF) in ambulatory patients. We sought to assess the HR accuracy of two commercially available smart watches [SW] (Fitbit Charge HR [FB] and Apple Watch Series 3 [AW]) compared with Holter monitoring in an ambulant patient cohort.Thirty-two participants ≥18 years referred for 24-hour Holter monitoring were prospectively recruited. Each participant was randomly allocated to wear either a FB or AW along with their Holter monitor.Across all devices, 53,288 heart rate values were analysed from 32 participants. Twenty wore the AW (17 had persistent AF and 3 had sinus rhythm [SR]) while 12 participants wore the FB (9 in persistent AF and 3 in SR). Participants in SR demonstrated strong agreement compared to Holter monitoring (bias1 beat, limits of agreement [LoA] -11 to 11 beats). In AF, both devices underestimated HR measurements (bias -9 beats, LoA -41 to 23). The degree of underestimation was more pronounced when HR 100 bpm (bias of -28 beats for HR range 100-120 bpm, -48 for 120-140 bpm, and -69 for140 bpm) compared to a slower HR (bias of -6 for HR range 80-100 bpm,1 for 60-80 bpm, and -1 for60 bpm).In ambulatory patients, smartwatches underestimated HR in AF particularly at HR ranges100 bpm. Further improvements in device technology are needed before integrating them into the clinical management of rate control in AF.

Background Patients at our pediatric outpatient clinic were offered 24-h Holter electrocardiogram (ECG) before and after 3-month period of dietary supplementation with omega-3 fatty acids to monitor the effect on heart rate variability (HRV) and arrhythmias. Methods The study included 17 children (mean age: 11.6 ± 4.9 years) with >1% premature ventricular contractions (PVC) at baseline. 24-h Holter ECG monitoring was performed before and after omega-3 fatty acid supplementation (mean duration: 143 days). Results Compared with 86 age-matched healthy control children, baseline HRV was significantly reduced and mean heart rate was significantly increased in children with frequent PVC. After omega-3-fatty acid supplementation, the mean heart rate decreased from 92.6 ± 3.4 bpm to 83.9 ± 9.9 bpm (p = 0.001), while global HRV showed a significant increase [standard deviation of all NN intervals (SDNN): 148.1 ± 34.4 ms vs. 126.5 ± 39.3 ms, p = 0.022)]. Enhanced vagal activity was indicated by significantly higher square root of the mean of the sum of the squares of differences between adjacent NN intervals (rMSSD) (42.3 ± 12.6 vs. 33.2 ± 14.8; p = 0.0003). PVC percentage significantly decreased by 45% (6.9 ± 7.0% vs. 12.1 ± 8.2%; p = 0.014). Conclusions Omega-3-fatty acid supplementation caused a 45% reduction in frequent PVC in children with structurally healthy hearts. This antiarrhythmic effect was likely attributable to improved autonomic function, which is consistent with previous findings in children with obesity, attention deficit disorder, and short stature.

Objectives To analyze the timing of appearance of conduction abnormalities (CAs) after transcatheter aortic valve implantation (TAVI), to identify predictors of delayed CAs requiring pacemaker (PM) implantation and to provide guidance regarding the duration of telemetry monitoring. Background How long patients remain at risk of development of CAs requiring PM implantation after TAVI and for how long they should be monitored remains unclear but is crucial when considering early discharge. Methods Development of CAs was studied in 701 consecutive patients treated with Edwards Sapien 3 valves and monitored with telemetry for 7 days in a single center. After excluding valve-in-valve procedures and patients with previous PM, 606 patients remained for analysis. Predictors of CAs requiring PM and the time of onset of CAs were analyzed. Results Of 606 patients 76 (12.5%) required a PM after TAVI. CAs requiring PM implantation occurred after 48 h in 22.4% (17 patients) and in 10.5% (8 patients) even after 5 days. Of the patients who developed high grade CAs requiring PM after 48 h, 47.1% had no CAs prior to TAVI, and 23.5% had neither pre-existing CAs nor new-developed CAs within the first 48 h after TAVI. Conclusion After TAVI using a new-generation balloon-expandable valve, delayed development of CAs requiring PM implantation is not uncommon, even after 5 days. More importantly, 23.5% of patients eventually requiring a delayed PM implantation had still no CAs at 48 h after TAVI in this study. These results question the safety of early discharge and support ECG monitoring for a longer time period. The most optimal way to monitor these patients is yet to be determined.

Background: The presence of reperfusion ventricular arrhythmias (VA) has been shown to correlate with larger infarct size (IS). However it is unclear whether the initial area at risk (AAR), also a determining factor for IS, is responsible for this correlation. We hypothesized that IS would be significantly larger in the presence of VA, while AAR would not differ. Methods: 68 STEMI patients from the MAST study with 24-hour, continuous, 12 lead Holter monitoring initiated prior to primary percutaneous coronary intervention (PCI) resulting in TIMI 3 flow post PCI were included. VA bursts were identified against subject-specific background VA rates using a previously validated statistical outlier method. IS, and infarct endocardial surface area (ESA) were obtained using CMR at mean 4.9 days after admission. Holter and CMR results were determined in core laboratories blinded to all other data. Results: VA bursts were present in 69% (45/65) of patients. No significant differences were found for demographic characteristics, comorbidities, infarct location, number of diseased coronary vessels, or duration of ischemia between groups with and without VA burst. IS was significantly smaller in the group without VA bursts (median 9.3% vs 17.0%; p=0.025). Infarct ESA did not significantly differ between the population with and without VA burst; median 24.3% vs 20.0%; p=0.15. Conclusion: VA bursts are a marker for larger IS independent of AAR, assessed by surrogate markers. These findings support the hypothesis that VA bursts are a marker of reperfusion damage occurring downstream at myocellular level. (c) 2018 Elsevier B.V. All rights reserved.

To evaluate the performance of a single‑lead, 14-day continuous electrocardiogram (ECG) patch for the detection of arrhythmias compared to conventional 24-h monitoring.This prospective clinical trial enrolled patients suspected of arrhythmias but not diagnosed by 12‑lead ECGs. Each patient underwent a 24-h Holter and 14-day ECG patch simultaneously. Seven types of arrhythmias were classified: supraventricular tachycardia (SVT, repetitive atrial beats4 beats), irregular SVT without P wave (4 beats), AF/AFL (irregular SVT without P wave ≥30 s), pause ≥3 s, atrioventricular block (AVB; Mobitz type II, third-degree, two to one or high degree AVB), ventricular tachycardia (VT), and polymorphic VT.A total of 158 patients were recruited (mean wear time:12.3 ± 3.2 days). The overall arrhythmia detection rate was higher with 14-day ECG patches (59.5%) compared to 24-h Holter (19.0%, P0.001). Up to 87.2% of arrhythmias recorded with 14-day ECG patches were not associated with symptoms. The 14-day ECG patch was associated with higher detection rates compared to the 24-h Holter in patients with SVT (52.5% versus 15.8%, P0.001), irregular SVT without P wave (12.7% versus 4.4%, P = 0.002), AF/AFL (9.5% versus 3.8%, P = 0.042), and critical arrhythmias (pause ≥3 s, AVB, VT, polymorphic VT) (16.5% versus 2.5%, P0.001). The 14-day ECG patch detected more than 2 types of arrhythmias in 5.1% of patients. No serious adverse events in patients wearing the 14-day ECG patch were reported.The 14-day ECG patch outperformed 24-h Holter to detect overall, asymptomatic, critical and multiple arrhythmias. It is safe and has the potential to identify individuals with hidden arrhythmias, especially those with critical arrhythmias.

We hypothesized patients implanted with ILRs for cryptogenic stroke in "real life" clinical practice will show an AF detection rate comparable to prior clinical studies, and that clinical or imaging features may help to identify those at higher risk of AF detection.A retrospective chart review was conducted of all patients who presented with cryptogenic stroke and received an ILR at an academic medical center from 2015 to 2017 with an active inpatient stroke service. The electronic health record and remote monitoring were used to identify occurrence of AF.A total of 178 patients who received ILRs for cryptogenic stroke were included. Overall, after a thorough evaluation for other etiologies of stroke, 35 (19.6%) were found to have AF detected. Mean follow-up was 365 days with a median time to detection of 131 days. Advanced age (p = 0.001), diastolic dysfunction on echo (p = 0.03), as well as ECG findings of premature atrial contractions (PACs) and p wave dispersion (PWD) 40 ms were found to be predictive of AF detection (p = 0.04, p 0.001, respectively). On multiple regression analysis, the only independent predictor of AF detection was PWD 40 ms.After a thorough evaluation to exclude other etiologies for stroke, approximately 20% of patients of our cryptogenic stroke population were found to have AF with ILR surveillance. Advanced age, diastolic dysfunction, as well as ECG findings of PACs and increased PWD may help to predict those at higher risk of AF detection, while PWD was the only independent predictor. This has important clinical implications, as better prediction of AF may help identify those at highest risk and might subsequently aid in guiding therapy.

Background Screening strategies to diagnose previously undetected atrial fibrillation (AF), especially silent AF (SAF), in at-risk populations may help reduce the number of strokes. We prospectively assessed the incidence rate of AF, including SAF, using an automated AF-detection capable sphygmomanometer in the General Practitioner (GP) setting. Methods This was a population-based prospective study of unselected general population of ≥65 years without prior AF. Participating GPs were requested, in the period February 2018–April 2019, to record all AF diagnoses including those derived from the AF-detection capable sphygmomanometer and confirmed by 12‑lead ECG or ECG Holter in asymptomatic patients. Results Overall, 14,987 patients assisted by 76 GPs accumulated 16,838 patient-years of follow up. The incidence rate of AF was 2.25% patient-years (95%CI 2.03–2.48). AF was more frequently detected in male, older, overweight, and patients with prior stroke, congestive heart failure, and chronic kidney disease. One in four patients had device-detected SAF (0.56% patient-years, 95%CI 0.46–0.69). Age, overweight, and the number of annual visits, were independent predictors of both SAF and AF. In addition, congestive heart failure, mitral valve disease were independent predictors of AF. Due to the interaction between blood pressure and age the risk of AF increased exponentially after 75 years of age in patients with higher systolic blood pressure values. Conclusion We found a higher than previously reported incidence rate of AF possibly by capturing SAF. Our simple protocol might be feasible in large-scale screening for AF and SAF in routine GP care.

Background Continuous monitoring by implantable loop recorder (ILR) can provide information relevant to rhythm control and oral anticoagulation (OAC) after atrial fibrillation (AF) ablation, but there is little agreement on patients' selection and appropriate management strategy. Methods An expert panel (EP) made up of eight Italian electrophysiologists with expertise in AF ablation, gathered to define an algorithm to guide continuous rhythm monitoring in AF patients who have undergone ablation. The process included a review of the current literature and two EP face-to-face meetings. Between the two meetings, an on-line survey was sent to 50 Italian electrophysiologists practicing AF ablation. Agreement level was considered reached when ≥70% of respondents agreed or were neutral. Results Two algorithms were developed to define patients for whom the ILR would be suggested support for (OAC) therapy discontinuation and rhythm management after AF ablation. Thirty-three out of 50 physicians responded to on-line survey (66% response rate). Together with EP members the responders accounted for electrophysiology centers performing about 50% of total yearly Italian AF ablation procedures. Agreement level was reached at the first survey round on all the questions, so the algorithms were not further modified and re-tested. Conclusions EP developed two algorithms for ECG monitoring to guide OAC therapy discontinuation and rhythm management after AF ablation. These suggestions, validated by wide feedback and consensus of physicians performing AF ablations, might support the decision on the choice and the use of ECG monitoring techniques, based on specific patient characteristics.

A correct measurement of the QT interval in the out-of-hospital setting is important whenever the long QT syndrome (LQTS) is suspected or a therapy might lead to drug-induced LQTS (diLQTS) because QT interval monitoring in the initial days of therapy could alert to dangerous QT prolongation. We explored whether automated QTc measurements (BGM) by BodyGuardian™ (BG), a wearable remote monitoring system, are sufficiently reliable compared to our own manual measurements (MM) performed on the same beats during 12‑lead Holter recordings in LQTS patients (pts) and in healthy controls.We performed 351 measurements in 20 LQTS pts and 16 controls. MM and BGM were compared by a Bland-Altman plot (BAp). High values of BAp indicate large differences between measurements.In all 36 subjects QTc was 446 ± 41 and 445 ± 47 ms in MM and BGM, respectively. The mean ± SE BAp was -1.4 ± 1.8 ms for QTc in all subjects, 8.3 ± 2.3 and -7.2 ± 2.5 ms respectively in controls and LQTS. The disagreement between BGM and MM15 ms in all, in controls, and in LQTS was respectively 57%, 63% and 54%. Among controls, there were only 3/132 false positive measurements (BGM QTc470 ms when MM QTc440 ms) in 3 different subjects. Among LQTS, there were 10/219 false negative measurements (BGM QTc440 ms when MM QTc470 ms) in 6 pts, but only two had multiple false negative values.This wearable monitoring system reliably identifies a prolonged QT interval and probably also subjects at risk for diLQTS.

Background Despite studies demonstrating the accuracy of smart watches (SW) and wearable heart rate (HR) monitors in sinus rhythm, no data exists regarding their utility in arrhythmias. Methods 102 hospitalized patients were evaluated at rest using continuous electrocardiogram (ECG) monitoring with concomitant SW-HR (FitBit, FB, Apple Watch, AW) for 30 min. Results Across all devices, 38,616 HR values were recorded. Sinus rhythm cohort demonstrated strong agreement for both devices with a low bias (FB & AW Bias = 1 beat). In atrial arrhythmias, AW demonstrated a stronger correlation than FB (AW rs = 0.83, FB rs = 0.56, both p Conclusions SW demonstrate strong agreement for HR estimation in sinus rhythm and atrial flutter but underestimates HR in AF. Tachycardic episodes recorded at rest on a SW may be suggestive of an underlying atrial tachyarrhythmia and warrant further clinical evaluation. Clinical trial registration Australian New Zealand Clinical Trials Registry (www.anzctr.org.au) ACTRN: 12616001374459.

We describe the feasibility of monitoring with a Textile Wearable Holter (TWH) in patients included in Crypto AF registry.We monitored cryptogenic stroke patients from stroke onset (3days) continuously during 28days. We employed a TWH composed by a garment and a recorder. We compared two garments (Lead and Vest) to assess rate of undiagnosed Atrial Fibrillation (AF) detection, monitoring compliance, comfortability (1 to 5 points), skin lesions, and time analyzed. We describe the timing of AF detection in three periods (0-3, 4-15 and 16-28days).The rate of undiagnosed AF detection with TWH was 21.9% (32 out of 146 patients who completed the monitoring). Global time compliance was 90% of the time expected (583/644h). The level of comfortability was 4 points (IQR 3-5). We detected reversible skin lesions in 5.47% (8/146). The comfortability was similar but time compliance (in hours) was longer in Vest group 591 (IQR [521-639]) vs. Lead 566 (IQR [397-620]) (p=0.025). Also, time analyzed was more prolonged in Vest group 497 (IQR [419-557]) vs. Lead (336h (IQR [140-520]) (p=0.001)). The incidence of AF increases from 5.6% (at 3days) to 17.5% (at 15th day) and up to 20.9% (at 28th day). The percentage of AF episodes detected only in each period was 12.5% (0-3days); 21.7% (4-15days) and 19% (16-28days).28days Holter monitoring from the acute phase of the stroke was feasible with TWH. Following our protocol, only five patients were needed to screen to detected one case of AF.

Excessive atrial ectopic activity (EAEA) has been related with an increased risk of atrial fibrillation (AF) and stroke but different cutoff values have been used. We aimed to determine the association between EAEA and stroke, AF and overall death.Consecutive 24-hour Holter monitoring performed between 2005 and 2010 in a single center was evaluated. Patients with a previous diagnosis of stroke or AF were excluded. The number of premature atrial contractions (PACs) during 24h was analyzed in 2480 subjects and according to that 3 sub-groups were defined:97PACs/h (above the top 5th percentile of the population) (EAEA+); intermediate value of PACs/h (below the top 5th percentile but above 30PACs/h) (EAEA+/-) and30PACs/h (EAEA-).After adjusting for risk factors, laboratory findings and medication, EAEA+ was associated with ischemic stroke (hazard ratio [HR] 2.83; 95% confidence interval [CI], 1.65-4.84, p0.001). Both EAEA+ and EAEA+/- were independently associated with AF (HR 2.05; 95% CI 1.31-3.23, p=0.010 for EAEA+ and HR 1.90; 95% CI 1.10-2.78, p=0.020 for EAEA+/-) and overall death (HR 2.17; 95% CI 1.48-3.28, p=0.031 for EAEA+; HR 2.01; 95% CI 1.06-2.52, p=0.029 for EAEA+/-).In this population, having30PACs/h was independently associated with a higher risk of AF and overall death but only subjects with97PACs/h had a higher risk of ischemic stroke. In the majority of subjects with stroke and EAEA+, AF has not been detected before stroke event.

This editorial refers to “Real-world experience with implantable loop recorder monitoring to detect subclinical atrial fibrillation in patients with cryptogenic stroke: the value of p wave dispersion in predicting arrhythmia occurrence” by Marks et al., published in the International Journal of Cardiology (2020).

Background The NECTAR-HF study evaluated safety and feasibility of vagal nerve stimulation (VNS) for the treatment of heart failure patients. The first six-month randomized phase of the study did not show improvement in left ventricular remodelling in response to VNS. This study reports the 18-month results and provides novel findings aiming to understand the lack of efficacy of VNS, including a new technique assessing the effects of VNS. Methods Ninety-six patients were randomized 2:1 to active or inactive VNS for 6months, thereafter VNS was activated for all patients. The primary safety endpoint was 18-month all-cause mortality. Results Ninety-one patients continued in the long-term evaluation with active VNS. The on-therapy survival estimate at 18months was 95% with a 95% one-sided lower confidence limit of 91%, (better than the predefined criterion). Left ventricular systolic volume decreased in the crossover group (VNS OFF→ON; 144±37 to 139±40, p 0.05) and LVEF (33.2±4.9 to 33.3±6.5, p>0.05) did not change. A new technique to detect subtle heart rate changes during Holter recordings, i.e. "heat maps", revealed that VNS evoked heart rate response in only 13/106 studies (12%) at 6 and 12months with active VNS. Conclusions Although a favourable long-term safety profile was found, improvements in the efficacy endpoints were not seen with VNS. A new technique for detecting acute heart rate responses to VNS suggests that the recruitment of nerve fibres responsible for heart rate changes were substantially lower in NECTAR-HF than in pre-clinical models.

Premature ventricular contraction (PVC) QRS duration (QRSd) and high PVCs burden are known as a risk factor of PVC-induced cardiomyopathy (CMP). The aim of this study is to find useful algorithm to predict PVC-induced CMP.180 patients (99 males, 51±14years) with frequent PVCs (10%/24h), who underwent successful PVC ablation, were studied. Typical PVC-related symptoms were defined as the presence of palpitations or dropped beats during PVC. Group A (n=144) was symptomatic and Group B (n=36) was asymptomatic.The incidence of CMP was significantly higher in group B (group A=19%, group B=66%, p0.001). In group A, there were significant differences, between the patients with normal EF and CMP, in terms of sex (p=0.005), daily PVC burden (p=0.012), distribution of PVCs with a LV site (p0.009), and PVC QRSd (p0.001). In group B, the PVC QRSd was significantly wider in patients with CMP. Multivariate analysis showed that PVC QRSd (p0.001), PVC burden (p=0.022), and LV site (p=0.043) were risk factors for CMP.Using our scoring algorithm for this patient sample, we are able to predict the development of PVC-induced CMP with 80% sensitivity, 81% specificity, 64% positive predictive value, and 91% negative predictive value.

Background Guidelines recommend that implantable loop recorders (ILRs) are used in the evaluation of people with recurrent unexplained syncope in the absence of high-risk criteria, and in high-risk patients after a negative evaluation. The aim of this systematic review was to analyze the diagnostic yield of ILRs in these patients. Methods We performed a systematic search in order to retrieve studies enrolling adults undergoing ILR implantation for undetermined syncope. The primary outcome was the overall diagnostic yield, defined as the proportion of patients with syncope recurrence and an available ILR recording or an automatic detection of a significant arrhythmia. Secondary outcomes were the proportions of patients with the specific etiologic diagnoses on the total of subjects and the proportion of an analyzable ECG recording during symptoms. We used a random effects model for the meta-analyses. Results Forty-nine studies, enrolling 4381 subjects, were included. The overall diagnostic yield was 43.9% (95% CI=40.2%, 47.6%; I 2 =79.8%). The proportions of subjects finally diagnosed with arrhythmic syncope, ventricular arrhythmias, supraventricular arrhythmias and bradyarrhythmias were 26.5%, 2.7%, 4.9% and 18.2%, respectively. The proportion of an analyzable ECG recording during symptoms was 89.5% (95% CI=86.1%, 92.1%; 1236 subjects; 36 studies; I 2 =44.9%). Median time to diagnosis was 134days. Heterogeneity is an important limitation to be acknowledged. Conclusions About a half of unexplained syncope subjects implanted with an ILR were diagnosed, and around 50% of them had an arrhythmia. Life-threatening arrhythmias as well as ILR complications and death due to arrhythmic events were very rare.

Background Gender differences in the penetrance and clinical expression of genetic mutations have been reported in patients with arrhythmogenic right ventricular (RV) dysplasia/cardiomyopathy (ARVD/C). Our study aimed at clarifying the impact of gender on ventricular substrates and clinical outcomes after radiofrequency catheter ablation (RFCA). Methods Patients with ARVD/C underwent RFCA for drug-refractory ventricular arrhythmias (VAs) were consecutively enrolled. Baseline characteristics, electrocardiograms, ventricular substrates, and VA recurrences after RFCA were extracted for comparison between genders. Results A total of 70 consecutive unselected patients with definite ARVD/C (36 men [51%], age 45±14years) were studied. Male patients had a higher incidence of sustained ventricular tachycardia and ventricular fibrillation or sudden cardiac arrest as initial manifestations. Electroanatomical mapping demonstrated that men with ARVD/C had a larger epicardial RV unipolar low-voltage zone, a larger endocardial and epicardial area with late potentials, and longer local abnormal ventricular activity. Cox regression analysis demonstrated that gender and late potential area predicted the recurrences of VAs. Conclusion Patients with ARVD/C displayed different characteristics of VAs and substrate properties between men and women. Male gender and the presence of larger area of abnormal electrograms independently predicted VA recurrences after RFCA.

Background The increasing use of conducted electronic weapons (CEW) cause concern regarding its secure application, specially regarding the implications in the cardiovascular system. Methods The objective was to determine Spark CEW safety through cardiovascular parameters analysis of healthy volunteers subjected to its use. Results Volunteers over 18years without cardiovascular disease or recent use of illegal drugs were submitted, before and after being affected with Spark CEW, to clinical evaluation; blood collection for serum laboratory tests; transthoracic electrocardiography at rest, transthoracic echodopplercardiogram and 24hour Holter. Results All 71 patients reported being incapable of any voluntary reaction during the shock of the application time. No arrhythmia or myocardial necrosis was related to the use of non-lethal weapon SPARK. Reported adverse events were self-limited, and mostly mild. Conclusions SPARK brand CEW is effective in incapacitating individuals by the shock of the application time, without causing.

Background This study assessed the acute effect of 21 days of challenging exercise on heart structure and function in recreationally active people across a range of age categories. Methods 15 recreationally active people completed a 21-day fundraising cycling ride (MADRIDE) over a distance of 3515 km. Twenty-four hour Holter electrocardiography and blood biochemistry analyses were performed before and after the MADRIDE. Results Incidence of cardiac arrhythmia was higher after MADRIDE (OR: 5.93; 95% CI: 5.68–6.19), with increases in both ventricular arrhythmias (OR: 9.90; 95% CI: 9.27–10.57) and supraventricular arrhythmias (OR: 3.09; 95% CI: 2.91–3.29). Adults (OR: 11.45; 95% CI: 7.41–17.69) and older adults (OR: 10.42 95% CI 9.83–11.05) were approximately 10 times more likely to experience arrhythmias after the MADRIDE. Whereas, young participants experienced 18% less cardiac arrhythmias after MADRIDE (OR: 0.82; 95% CI: 0.75–0.90). Aortic valve max velocity was reduced (MD: −0.12 m/s; 95% CI: −0.19–0.05 m/s) and mitral valve deceleration time was slower (MD: −28.91 m/s; 95% CI: −50.97–6.84 m/s) after MADRIDE. Other structural and functional characteristics along with heart rate variability were not different after MADRIDE. Conclusions Multi-day challenging exercise increased the incidence of both supraventricular and ventricular arrhythmias in active adults and older adults. Increases in arrhythmia rates after MADRIDE occurred without changes in cardiac structure and autonomic control. Further exploration is necessary to identify the causes of exercise-induced cardiac arrhythmia in adult and older adults.

Background Severe mitral stenosis is usually symptomatic and is treated by BMV or surgery, whereas mild to moderate mitral stenosis is usually asymptomatic or mildly symptomatic and managed medically. Patients in the later group may become symptomatic during episodes of exercise and increased heart rate. Beta-blockers are frequently used in patients with mitral stenosis to control the heart rate and alleviate exercise-related symptoms. The objective of our study was to investigate the comparative efficacy of ivabradine versus metoprolol in patients with mitral stenosis in sinus rhythm. Methods We studied 97 patients of mitral stenosis in sinus rhythm presented with exertional symptoms. The effectiveness of Metoprolol was compared with ivabradine in alleviating these exertional symptoms in a randomized, open label non crossover study. We also assessed various stress ECG parameters, 24 hour Holter parameters and 2D Echo parameters to objectively compare the effects of ivabradine and metoprolol in these patients. Results Ivabradine and metoprolol both were effective in controlling exertional symptoms. Significant improvement in objective parameters like TMT (work capacity, baseline heart rate and maximal heart rate) and 2D echocardiography (right ventricular systolic pressure) are seen with both drugs. Ivabradine controls the exertional symptoms significantly more than metoprolol. On head to head comparison there was a significant benefit of working capacity and heart rate at maximal exercise in favour of ivabradine. Conclusions Ivabradine should be strongly considered in medical management of mitral stenosis patients where beta blockers are contraindicated such as reactive airway disease. The cost of ivabradine is higher than metoprolol which might possess constraints as most of the rheumatic heat disease patients belong to low socio economic status.

In patients with frequent premature ventricular contractions (PVCs), little is known about the profile of PVCs and the outcome of treatment in patients with mitral valve prolapse (MVP) compared to those without MVP.Patients with documented PVCs between January 2001 and October 2012 were divided into 2 groups: MVP and non-MVP. The PVC characteristics, efficacy of therapy, and outcome were compared between the 2 groups. A total of 112 patients with MVP and 952 without MVP were identified. The frequency of PVCs was similar between the 2 groups (P.05). In patients who underwent cardiac mapping, PVCs originating in papillary muscles (26.7% vs 2.3%; P.001) and fascicle (13.3% vs 3.4%; P.001) were more frequently seen in the MVP group than in the non-MVP group, which raises the difficulty of catheter ablation. The 2 groups had similar response to catheter ablation or medical therapy (P.05). The survival rate was similar between the 2 groups (P=.95).In patients with significant PVC burden, MVP patients had similar PVC frequency, treatment outcome, and survival rate to those without MVP.

A tissue engineering approach to augment the left ventricular wall has been suggested as a means to treat patients with advanced heart failure. This study evaluated the safety and feasibility of Algisyl-LVR™ as a method of left ventricular augmentation in patients with dilated cardiomyopathy undergoing open-heart surgery.Eleven male patients (aged 44 to 74years) with advanced heart failure (NYHA class 3 or 4), a left ventricular ejection fraction (LVEF) of40% and requiring conventional heart surgery received Algisyl-LVR delivered into the LV myocardial free wall. Serial echocardiography, assessment of NYHA class, Kansas City Cardiomyopathy Questionnaire (KCCQ) and 24-hour Holter monitoring were obtained at baseline, days 3 and 8 (for echocardiography and Holter monitoring), and at 3, 6, 12, 18 and 24months. A total of 9 (81.8%) patients completed 24months of follow-up. Two patients withdrew consent after day 8 and at the 3month visit. Operative mortality was 0% (n=10 with 30day follow-up). There were no adverse events attributed to Algisyl-LVR. Mean LVEF improved from 27.1 (±7.3) % at screening to a mean LVEF of 34.8 (±18.6) % 24months post-discharge. Improvements of NYHA class were corroborated with improvements in KCCQ summary scores. Holter monitor data showed a significant decrease in the episodes of nonsustained ventricular tachycardia following administration of Algisyl-LVR.Administration of Algisyl-LVR to patients with advanced HF at the time of cardiac surgery is feasible and safe; warranting continued development of Algisyl-LVR as a potential therapy in patients with advanced HF.

Introduction The Heart Sentinel™ app (HS-app) is conceived to detect cardiac arrest during outdoor sports, automatically alerting contacts via SMS with GPS position data. It automatically starts the chain of survival in case no bystander has witnessed the event, using commercially-available chest strap heart monitor and a smartphone. The heart rate analysis arm of the algorithm is extremely sensitive, with specificity being addressed by motion analysis through smartphone sensors, since only unexpected prolonged absence of motion would confirm true cardiac arrest and start an alert code. We assessed the accuracy of such HS-app with simulated exercise-associated ventricular fibrillation (VF), and possible false positives in real-world athletes. Methods The occurrence of false positive alerts was tested in the outdoor field, through athletes regularly running and cycling, and with ECG simulators. The occurrence of false negatives for VF detection was assessed with 3 different ECG simulators, using VF simulation protocols. Results The false positive initiation of an alert countdown was recorded twice during 829 h of outdoor sports. Both athletes were able to stop such false positive 15-second countdown before the alert SMS was dispatched. No false positive SMS was dispatched. False negatives were not recorded under any simulation protocol. Conclusion A simple smartphone app, using commercially-available heart rate monitors, is promising to detect cardiac arrest caused by VF during sports, triggering automatic dispatch of emergency SMS with GPS position. During outdoor exercise, HS-app would be helpful for cases of exercise-associated cardiac arrest.

Objective: To investigate the inflammatory biomarker signature associated with classical orthostatic hypotension (OH). Methods: A cross-sectional study including 778 patients with unexplained syncope and/or orthostatic intolerance undergoing head-up tilt test (HUT) and supine blood sampling. Of these, 98 met diagnostic criteria of classical OH and 181 demonstrated normal haemodynamic response during HUT. Blood plasma samples were analysed by antibody-based Proximity Extension Assay technique simultaneously measuring 57 inflammatory and cancer-related human protein biomarkers. The discovery algorithm was a sequential two-step process of biomarker signature identification by multivariate principal component analysis (PCA), and verification by univariate ANOVA with Bonferroni correction. Results: Patients with classical OH were older (68 vs. 60 years; p < 0.001) and more likely to be men (58 vs. 41%; p < 0.001). PCA and Bonferroni-adjusted ANOVA identified midkine (MK), immunoglobulin-like transcript 3 (ILT-3), regenerating islet-derived protein 4 (REG-4), and tartrate-resistant acid phosphatase type 5 (TR-AP) as the most robust targeted biomarker signature for OH. In multivariate regression analysis adjusting for age, sex, cardiovascular disease and risk factors, the results remained significant for ILT-3 (p = 0.036), MK (p = 0.008) and REG-4 (p = 0.024), but not for TR-AP. Conclusions: Targeted protein profiling in classical orthostatic hypotension reveals a biomarker signature associated with immunoregulatory functions and vascular inflammation. Circulating levels of midkine, immunoglobulin-like transcript-3, regenerating islet-derived protein-4 are elevated in orthostatic hypotension, suggesting a complex interplay among inflammation, autonomic dysfunction and atherothrombosis. (Less)

BackgroundPatients with autosomal-recessively inherited Friedreich's ataxia (FA) may develop a hypertrophic cardiomyopathy (CM), which potentially progresses towards a life-limiting problem. The typical features of this CM and the sequence of progression are widely unknown.MethodsThirty-two consecutive patients with genetically confirmed FA were included. All patients received resting electrocardiogram (ECG), 24-hour Holter-ECG, echocardiography with speckle tracking imaging, cardiac magnetic resonance imaging (cMRI) with late enhancement imaging (for replacement fibrosis), and measurement of high-sensitive troponin-T (hsTNT). In addition, morphological parameters were retrospectively compared to data obtained five years before.ResultsBased on criteria comprising ejection fraction (

Aim To assess the degree and progression of cardiac involvement in patients with limb-girdle type 2 (LGMD2) and Becker muscular dystrophies (BMD). Methods A follow-up study of 100 LGMD2 (types A–L) and 30 BMD patients assessed by electrocardiogram (ECG) and echocardiography, supplemented by Holter-monitoring at follow-up. Results After a median of 8.9years (range 0.4–13.7), twelve patients had died: LGMD2 (n=10, mean age 61±11years), BMD (n=2, age 43 and 45years). Of the remaining 118 patients, 89 completed follow-up: LGMD2 (n=64, age 48±13years) and BMD (n=25, age 40±13years). In BMD, LVEF decreased from 60% (10–62) to 50% (10–64), p=0.02 corresponding to a one percentage drop annually. Among patients with LGMD2, LVEF decreased significantly in patients with LGMD type 2I (n=28) from 59% (15–72) to 55% (20–61), p=0.03, i.e. a 0.4 percentage drop annually, and LVEF≤50% was associated with increased mortality in this subgroup. In LGMD2E, 3/5 patients (60%) at baseline and 4/5 (80%) at follow-up had LVEF≤50%. ECG abnormalities were non-progressive in BMD and in all subgroups of LGMD2. SVT and NSVT were present in both groups: BMD (3/14 (21%) and (2/14 (14%)), LGMD2 (16/51 (31%) and 8/51 (16%)), respectively, all asymptomatic. Conclusion LVEF decreased significantly in patients with BMD and LGMD2I, and the majority of patients with LGMD2E had left ventricular systolic dysfunction. This study emphasizes the need for tailored regular cardiac assessments according to molecular diagnosis with special focus on BMD and LGMD types 2I and 2E.

Background Multiform premature ventricular complexes (PVCs) are common electrocardiographic abnormalities in patients with structurally normal hearts. However, the prognostic value of these complexes remains unclear. This study aimed to clarify the role of PVC polymorphism in predicting adverse outcomes. Methods and result We examined the database for 24-hour electrocardiography monitoring between January 1, 2002 and December 31, 2004. We analyzed 3351 individuals with apparently normal hearts. Kaplan–Meier curves and multivariate Cox proportional hazards models were employed to estimate the effect of multiform PVC and uniform PVC on the number of incident adverse events. Average follow-up time was 10±1years. Patients with multiform PVC were older and had a higher prevalence of comorbidities. In multivariate analysis, patients with multiform PVC had an increased incidence of mortality (hazard ratio [HR]: 1.642, 95% confidence interval [CI]: 1.327–2.031), hospitalization (HR: 1.196, 95% CI: 1.059–1.350), cardiovascular hospitalization (HR: 1.289, 95% CI: 1.030–1.613), new-onset heart failure (HF; HR: 1.456, 95% CI: 1.062–1.997), transient ischemic accident (HR: 1.411, 95% CI 1.063–1.873), and new-onset atrial fibrillation (AF; HR: 1.546, 95% CI: 1.058–2.258) compared to the group without PVC. Patients with multiform PVC had a higher rate of mortality (HR: 1.231, 95% CI: 1.033–1.468) and all cause-hospitalization (HR: 1.147, 95% CI: 1.025–1.283) compared with patients with uniform PVC. Conclusion The presence of multiform PVC was associated with a higher incidence of mortality, hospitalization, transient ischemic attack, new-onset AF, and new-onset HF independent of other clinical risk factors.

Objective Pre-clinical evidence suggests delivery of nitric oxide (NO) through administration of inorganic nitrite suppresses arrhythmias resulting from acute ischaemia and reperfusion (I/R). To date no assessment of whether inorganic nitrite might limit reperfusion arrhythmia has occurred in man, therefore we explored the effects on I/R-induced ventricular arrhythmias in the NITRITE-AMI cohort. Methods In the NITRITE-AMI cohort, Holter analysis was performed prior to and for 24 h after primary PCI in 80 patients who received either intra-coronary sodium nitrite (N = 40) or placebo (N = 40) during primary PCI for AMI. Results Ventricular rhythm disturbance was experienced by 100% patients; however, there was no difference in the number between the groups, p = .2196. Non-sustained ventricular tachycardia (NSVT) occurred in 67.5% (27/40) of nitrite-treated patients compared to 89% (35/39) of those treated with placebo (p = .027). There was a significant reduction in both the number of runs (63%, p ≤.0001) and total beats of NSVT (64%, p = .0019) in the nitrite-treated patients compared to placebo. Post-hoc analyses demonstrate a direct correlation of occurrence of NSVT with infarct size, with the correlation stronger in the placebo versus the nitrite group initiating an independent nitrite effect (Nitrite: r = 0.110, p = .499, placebo: r = 0.527, p = .001, p for comparison: 0.004). Conclusion Overall no difference in ventricular rhythm disturbance was seen with intra-coronary nitrite treatment during primary PCI in STEMI patients, however nitrite treatment was associated with an important reduction in the incidence and severity of NSVT. In view of the sustained reduction of MACE seen, this effect warrants further study in a large-scale trial.

INTRODUCTION: Supraventricular ectopic complexes (SVEC) are known risk factors of recurrent atrial fibrillation (AF). However, the impact of SVEC in different age groups is unknown. We aimed to investigate the risk of AF recurrence with higher SVEC burden in patients ±57years, respectively, after treatment with antiarrhythmic medication (AAD) or catheter ablation (CA).METHODS: In total, 260 patients with LVEF >40% and age ≤70 years were randomized to AAD (N=132) or CA (N=128) as first-line treatment for paroxysmal AF. All patients underwent 7-day Holter monitoring at baseline, and after 3, 6, 12, 18 and 24months and were categorized according to median age ±57years. We used multivariate Cox regression analyses and we defined high SVEC burden at 3months of follow-up as the upper 75th percentile >195SVEC/day. AF recurrence was defined as AF ≥1min, AF-related cardioversion or hospitalization.RESULTS: Age >57years were significantly associated with higher AF recurrence rate after CA (58% vs 36%, p=0.02). After CA, we observed a higher SVEC burden during follow-up in patients >57years which was not observed in the younger age group treated with CA (p=0.006). High SVEC burden at 3months after CA was associated with AF recurrence in older patients but not in younger patients (>57years: HR 3.4 [1.4-7.9], p=0.005). We did not find any age-related differences after AAD.CONCLUSION: We found that younger and older patients respond differently to CA and that SVEC burden was only associated with AF recurrence in older patients.

Background The long-term incidence of atrial fibrillation (AF) in cryptogenic stroke (CS) patients has been explored in carefully controlled clinical trials but real-world data are limited. We investigated the two-year incidence of AF in real-world clinical practice among a large cohort of patients with an insertable cardiac monitor (ICM) placed for AF detection following CS. Methods Patients in the de-identified Medtronic Discovery™ Link database who received an ICM (Reveal LINQ™) for the purpose of AF detection following CS were included and monitored for up to 2years. All detected AF episodes (≥2min) were adjudicated. We quantified the AF detection rate using Kaplan-Meier survival estimates, analyzed the median time to initial detection of AF, and simulated the ability of various intermittent monitoring strategies to detect AF. Results A total of 1247 patients (65.3±13.0years, 53% male) were included and followed for 579±222days. AF episodes (n=4183) were detected in 238 patients, resulting in an AF detection rate of 21.5% at 2years. The median time to AF detection was 112 [IQR 35–293] days. Intermittent monitoring for AF detection was inferior to continuous ICM monitoring with sensitivities ranging from 2.9% (annual 24-hour Holter) to 29.9% (quarterly 7-day Holters), p Conclusions AF episodes were detected via continuous monitoring with ICMs in approximately 1 of every 5 CS patients within 2years of follow-up. The vast majority of patients with AF would not have been detected with conventional external ambulatory monitors. ICMs should therefore be considered in the evaluation of CS patients.

Background Insertable cardiac monitors (ICM) are leadless devices utilized in long-term monitoring of the heart rhythm. The implantation procedure of the new-generation ICMs is minimally invasive, but little experience exists regarding complications. We thus aimed to investigate adverse events (AE) according to procedure-related characteristics after implantation of a large number of new-generation ICMs. Methods The study population consisted of participants randomized to receive ICM in a multi-center trial. The Reveal LINQ™ ICM was implanted using provided insertion tools, either in an electrophysiology laboratory or outpatient procedure room. If device sensing was insufficient in the first subcutaneous position, one or more repositions were performed. Patients were urged to make contact if they suspected any AE. Furthermore, follow-up for safety endpoints consisted of evaluation of medical records and planned study visits. Results 1420 patients received an ICM, 753 (53%) in a procedure room and 667 (47%) in an electrophysiology laboratory. During a median follow-up of 499days, 9 (0.63%) and 15 (1.13%) patients experienced AEs with and without need for device explantation, respectively. In the 38 patients requiring device repositioning, more AEs requiring explantation were seen (3 (7.9%) vs. 6 (0.4%), p =0.001). Patients undergoing implantation in a procedure room had more infections (12 (1.6%) vs. 1 (0.1%), p =0.004), though no significant difference was reached in AEs requiring explantation (7 (0.9%) vs. 2 (0.3%), p =0.19). Conclusion The Reveal LINQ™ ICM can be inserted with a very low risk of complications, both in the traditional electrophysiology laboratory setting and in an outpatient procedure room.

Sudden cardiac death occurs frequently in patients with heart failure [1,2]. Determining suitable factors for identifying high risk heart failure patients is necessary. Heart rate variability (HRV) [3] was previously demonstrated to predict sudden cardiac death in heart failure patients, though findings have been inconsistent [4]. We conducted a systematic review for clarifying the predictive value of HRV. A comprehensive literature search up to December 2013 using the PubMed (MEDLINE) and CENTRAL with restrictions to humans’ studies and English publications was carried out, with key words containing Sudden Cardiac Death, Heart Failure, and Heart Rate Variability. Among the 138 publications identified, 119 were excluded based on screening of titles and/or abstracts. 19 potential relevant articles and an additional article identified from references were fully reviewed. Six articles were excluded from our study due to different reasons. Jiang et al. included only death or a life-threatening cardiac event as the outcome but not covers sudden cardiac death [5]. Arsenos et al. included surrogate of sudden cardiac death as outcome [6]. Yamada et al. and Nessler et al. did not provide sufficient information [7,8]. La Rovere et al. did not provide specified data for outcome of sudden cardiac death [9]. Szabo et al. did not provide sufficient information for multivariate adjusted result of HRV parameters [10]. After excluding these 6 articles, 14 appropriate articles were retained (Fig. 1) [11–24]. Among them 4 articles have overlapping for participants of two studies [14,19,21,23]. We included all of them as in each article they demonstrated different variables/parameters of HRV. Further quality assessment in standardized manner [25] did not find deviations among these studies. Fig. 1 Articles identified through comprehensive literature search. In total, 14 articles representing 12 prospective studies were included. Detailed information for these articles is demonstrated in Table 1. These studies used quite different variables/parameters of HRV in their report, making an overall quantitative evaluation challenging [26,27]. As the main variable of HRV, standard deviation of all normal-to-normal intervals (SDNN) was mostly studied. While this variable was presented as numerical variable in several studies [12,13,21,22], in other studies it was categorized according to different values, making an overall numerical estimation difficult [11,14,18,20,23]. However, in all these 9 studies, SDNN did not show a predictive role; thus, this variable should have a limited role in predicting sudden cardiac death among heart failure patients. Similarly, some other studied variables, including SD derived from time-domain analysis [12], NN [12,14,23], SDANN [12–14,23,24], pNN50 [12–14,20], rMSSD [12,13,18,23], HRV index [13], sNN50 [18], log HRV [17] and RR [21], were demonstrated to be not predictive in most studies except that one study supported a marginal predictive role of SDANN and rMSSD [20]. Thus, overall these variables are less likely to be predictive of sudden death in heart failure patients. Table 1 Studies investigating predictive value of heart rate variability on cardiac sudden death in heart failure patients. Several other variables of HRV were demonstrated to be potentially predictive in more studies. High frequency power (HF/HFP) was shown to be predictive in the 2005 Greece study [12], and night HFP seemed to be predictive in the 2005 Italy study [21], while a null effect was shown in the 2000 and 2009 Japan study [13,15], the 1996 and 2009 Netherlands study [14,23], and the 2000 France study [20]. It thus makes HFP being predictive of sudden cardiac death in heart failure patients less possible, since the 2009 Japan study with a long following-up (65 months) showed null result [13]. On the other hand, low frequency power (LF/LFP) was predictive in the 2003 Italy study (2 independent samples) [19], besides day-time LFP in the 2000 France study [20] and night-time LFP in the 2005 Italy study [21]. However, the prediction was not demonstrated in the 2005 Greece study [12], the 2000 and 2009 Japan study [13,15], and the 1996 and 2009 Netherlands study [14,23]; also the 2005 Italy study showed that all LFP did not have a predictive effect [21]. Thus overall evidences supporting the predictive effect of LFP are also weak. Another HRV variable, Poincare plot, demonstrated strong prediction in available studies (the 1996 Netherlands and the 1997 US studies) [14,24]. Though limited by a small number of studies, the relatively small sample size and short following-up make this effect is likely real. To our knowledge, this is the first systematic review for the prediction value of heart rate variability on sudden cardiac death in heart failure patients. Although a quantitative meta-analysis is impossible due to that heart rate variability variables/parameters used in each study are quite different, all findings from these studies were carefully evaluated in our systematic review. We found that variables of SDNN, SD derived from time-domain analysis, NN, SDANN, pNN50, rMSSD, HRV index, sNN50, log HRV and RR should have limited predictive roles. Other two HRV variables, high frequency power and low frequency power, although showing a predictive value in several studies, are less likely to effectively predict sudden cardiac death in heart failure patients. On the other hand, Poincare plot can potentially predict well according to current evidences. Further studies are warranted to determine whether Poincare plot can really be a representative HRV variable in effectively predicting sudden cardiac death in heart failure patients.

Introduction Patients with atrial fibrillation (AF) with enlarged atria or previous pulmonary vein isolation (PVI) are challenging patients for catheter ablation. Thoracoscopic surgery is an effective treatment for these patients but comes at the cost of an increase in adverse events. Recently, electrophysiological (EP) guided approaches to thoracoscopic surgery have been described which consist of EP guidance by measurement of conduction block across ablation lines. In this study we describe the efficacy and safety of EP-guided thoracoscopic surgery for AF in patients with enlarged atria and/or prior failed catheter ablation. Methods & results A total of 72 patients were included. Two different approaches to EP-guided thoracoscopic surgery were implemented: epicardial or endocardial EP-guidance at the time of surgery. Residual intraoperative conduction requiring additional ablation was detected with epicardial or endocardial mapping techniques in 50% and 11%, respectively. Additional epicardial or endocardial ablation was performed until bidirectional block was confirmed. Follow-up consisted of an ECG and a 24h Holter at 3, 6 and 12months after the procedure. A total of 57 patients (79%) had freedom of AF and were off anti-arrhythmic drugs at one year follow-up (30 paroxysmal (83%), 27 persistent AF (75%)). Adverse events occurred in 13 patients (6 major). None of our patients died and all events were reversible. Conclusion EP-guidance of thoracoscopic surgery can be safely performed both epicardially and endocardially and is associated with a high rate of long-term maintenance of sinus rhythm in patients with enlarged atria and/or a previously failed ablation.

The presentation of atrial fibrillation (AF) varies remarkably, from totally asymptomatic to symptomatic patients, while the same individual may present symptomatic and asymptomatic episodes. We aimed to identify electrocardiographic differences between symptomatic and asymptomatic episodes and to find parameters related to the appearance of symptoms.Thirty consecutive patients (age 66.9±10years) with paroxysmal AF received an implantable loop recorder. Three types of episodes were defined: asymptomatic (ASx), symptomatic (Sx), and mixed asymptomatic-symptomatic (AS-Sx). The heart rate (HR) and heart rate variability (HRV) were recorded during the first 2min of each ASx or Sx episode, and during the first 2min of both the symptomatic and asymptomatic periods in AS-Sx.Eighty-two episodes from twenty-five patients were evaluated. Mean HR was 142.48±25.84bpm for Sx and 95.71±19.29bpm for ASx (p0.001). Mean HRV was 92.62±42.29ms for Sx and 150.06±49.68ms for ASx (p0.001). In AS-Sx, mean HR was 102.91±24.54bpm for the asymptomatic and 141.88±23.43bpm for the symptomatic period (p0.001). Mean HRV was 173.55±61.30ms for the asymptomatic and 87.33±30.65ms for the symptomatic period (p=0.003). There were no significant correlations between patients' characteristics and the clinical presentation of the arrhythmia.The ASx were characterized by a lower HR and higher HRV compared to Sx. In As-Sx, the asymptomatic period was characterized by a lower HR and higher HRV compared to the symptomatic. These findings suggest a possible contribution of variations in the autonomic nervous system activity to the perception of the arrhythmia.

This study looked to assess the care pathway and diagnostic yield in patients who received an implantable loop recorder (ILR) after an "initial phase of the diagnostic work-up" (initial work-up) or after a "full evaluation" of unexplained syncope.Physicians classified the timing of an ILR implant in 514 patients as either following an "initial work-up" (n=128; 25%) or "full evaluation" (n=386; 75%). Patients with an "initial work-up" underwent a median (IQ range) of 8 (6-14) tests prior to ILR implant compared to 14 (10-21) tests after "full evaluation" (p0.0001). Hospitalization and injury before implant were less common in patients with an "initial work-up": 53 vs. 75%, p0001, and 23% vs. 39%, p0.001, as were visits to specialists, e.g. neurologist, 32% vs. 50%, p0.001. At one year after implant, the syncope recurrence rate was 32% in the initial work-up group and 36% in the full evaluation group, and the incidence of recurrences with an ILR-guided diagnosis was 52% and 75% respectively. Diagnoses were cardiac in 90% after "initial work-up" vs. 79% after "full evaluation".Patients who only underwent an "initial work-up" had fewer investigations and a lower incidence of injury or hospitalization. The diagnostic yield from the ILR was high in both groups. Patients in both groups underwent more investigations than suggested in the ESC guidelines and could have benefitted from limiting the initial evaluation before an ILR is implanted.

Clinical and electrophysiological features of different initiation patterns of ventricular tachycardia (VT) have been widely studied. At least two different onset patterns of VT have been defined in the studies. Tachycardias, which are preceded by either a single or multiple ventricular ectopic activity, including a short-long-short sequence, are defined as nonsudden onset and those, which are not preceded by ventricular ectopy are defined as sudden onset. The knowledge of initiation pattern of VTs may have some clinical importance and can be essential for the selection of treatment strategies. The use of Holter electrocardiograms and analysis of intracardiac electrograms from implantable cardioverter-defibrillators enables to evaluate the initiation patterns of VTs.