Type 3 long QT syndrome: Is the effectiveness of treatment with beta-blockers population-specific?

BACKGROUND

The efficacy of beta-blocker treatment in type 3 long QT syndrome (LQT3) remains debated.

OBJECTIVES

The purpose of this study was to test the hypothesis that beta-blocker use is associated with cardiac events (CEs) in a French cohort of LQT3 patients.

METHODS

All patients with a likely pathogenic/pathogenic variant in the SCN5A gene (linked to LQT3) were included and followed-up. Documented ventricular tachycardia/ventricular fibrillation, torsades de pointes, aborted cardiac arrest, sudden death, and appropriate shocks were considered as severe cardiac events (SCEs). CEs also included syncope.

RESULTS

We included 147 patients from 54 families carrying 23 variants. Six of the patients developed symptoms before the age of 1 year and were analyzed separately. The 141 remaining patients (52.5% male; median age at diagnosis 24.0 years) were followed-up for a median of 11 years. The probabilities of a CE and an SCE from birth to the age of 40 were 20.5% and 9.9%, respectively. QTc prolongation (hazard ratio [HR] 1.12 [1.0-1.2]; P = .005]) and proband status (HR 4.07 [1.9-8.9]; P <.001) were independently associated with the occurrence of CEs. Proband status (HR 8.13 [1.7-38.8]; P = .009) was found to be independently associated with SCEs, whereas QTc prolongation (HR 1.11 [1.0-1.3]; P = .108) did not reach statistical significance. The cumulative probability of the age at first CE/SCE was not lower in patients treated with a beta-blocker.

CONCLUSION

In agreement with the literature, proband status and lengthened QTc were associated with a higher risk of CEs. Our data do not show a protective effect of beta-blocker treatment.

Position paper on sustainability in cardiac pacing and electrophysiology from the Working Group of Cardiac Pacing and Electrophysiology of the French Society of Cardiology

Sustainability in healthcare, particularly within the domain of cardiac electrophysiology, assumes paramount importance for the near future. The escalating environmental constraints encountered necessitate a proactive approach. This position paper aims to raise awareness among physicians, spark critical inquiry and identify potential solutions to enhance the sustainability of our practice. Reprocessing of single-use medical devices has emerged as a potential solution to mitigate the environmental impact of electrophysiology procedures, while also offering economic advantages. However, reprocessing remains unauthorized in certain countries. In regions where it is possible, stringent regulatory standards must be adhered to, to ensure patient safety. It is essential that healthcare professionals, policymakers and manufacturers collaborate to drive innovation, explore sustainable practices and ensure that patient care remains uncompromised in the face of environmental challenges. Ambitious national/international programmes of disease prevention should be the cornerstone of the strategy. It is equally vital to implement immediate actions, as delineated in this position paper, to bring about tangible change quickly.

Prognostic Value of Multiplexed Assays of Variant Effect and Automated Patch-clamping for KCNH2-LQTS Risk Stratification

Background

Long QT syndrome (LQTS) is a lethal arrhythmia condition, frequently caused by rare loss-of-function variants in the cardiac potassium channel encoded by KCNH2. Variant-based risk stratification is complicated by heterogenous clinical data, incomplete penetrance, and low-throughput functional data.

Objective

To test the utility of variant-specific features, including high-throughput functional data, to predict cardiac events among KCNH2 variant heterozygotes.

Methods

We quantified cell-surface trafficking of 18,323 variants in KCNH2 and recorded potassium current densities for 506 KCNH2 variants. Next, we deeply phenotyped 1150 KCNH2 missense variant patients, including ECG features, cardiac event history (528 total cardiac events), and mortality. We then assessed variant functional, in silico, structural, and LQTS penetrance data to stratify event-free survival for cardiac events in the study cohort.

Results

Variant-specific current density (HR 0.28 [0.13-0.60]) and estimates of LQTS penetrance incorporating MAVE data (HR 3.16 [1.59-6.27]) were independently predictive of severe cardiac events when controlling for patient-specific features. Risk prediction models incorporating these data significantly improved prediction of 20 year cardiac events (AUC 0.79 [0.75-0.82]) over patient-only covariates (QTc and sex) (AUC 0.73 [0.70-0.77]).

Conclusion

We show that high-throughput functional data, and other variant-specific features, meaningfully contribute to both diagnosis and prognosis of a clinically actionable monogenic disease.

Intracardiac electrophysiology to characterize susceptibility to ventricular arrhythmias in murine models

Introduction: Sudden cardiac death (SCD) and ventricular fibrillation are rare but severe complications of many cardiovascular diseases and represent a major health issue worldwide. Although the primary causes are often acute or chronic coronary diseases, genetic conditions, such as inherited channelopathies or non-ischemic cardiomyopathies are leading causes of SCD among the young. However, relevant experimental models to study the underlying mechanisms of arrhythmias and develop new therapies are still needed. The number of genetically engineered mouse models with cardiac phenotype is growing, making electrophysiological studies in mice essential tools to study arrhythmogenicity and arrhythmia mechanisms and to test novel treatments. Recently, intracardiac catheterization via the jugular vein was described to induce and record ventricular arrhythmias in living anesthetized mice. Several strategies have been reported, developed in healthy wild-type animals and based on aggressive right ventricular stimulation. Methods: Here, we report a protocol based on programmed electrical stimulation (PES) performed in clinical practice in patients with cardiac rhythm disorders, adapted to two transgenic mice models of arrhythmia - Brugada syndrome and cardiolaminopathy. Results: We show that this progressive protocol, based on a limited number of right ventricular extrastimuli, enables to reveal different rhythmic phenotypes between control and diseased mice. In this study, we provide detailed information on PES in mice, including catheter positioning, stimulation protocols, intracardiac and surface ECG interpretation and we reveal a higher susceptibility of two mouse lines to experience triggered ventricular arrhythmias, when compared to control mice. Discussion: Overall, this technique allows to characterize arrhythmias and provides results in phenotyping 2 arrhythmogenic-disease murine models.

Prophylactic epicardial pacemaker implantation in tricuspid valve replacement

OBJECTIVES

Patients undergoing surgical tricuspid valve replacement (TVR) are at high risk of atrioventricular conduction disorders. Because implanting a lead through the tricuspid bioprosthesis is discouraged, the patients who undergo TVR in our centre are usually given a prophylactic epicardial pacemaker. Our aim was to assess the benefits and risks of this strategy.

METHODS

Among the patients who underwent TVR with prophylactic epicardial pacemaker implantation, clinical evaluations and pacemaker reports were analysed retrospectively after surgery. The need for cardiac pacing were assessed by characterizing the atrioventricular conduction, while the risks were evaluated by listing and adjudicating post-operative events.

RESULTS

A total of 80 patients were analysed (mean age was 57 ± 16 years old, 30% males). TVR was isolated in 28 (35%) patients, but most often associated with another valve surgery. In the postoperative period, heart rhythm was analysed in 59/80 patients during a median follow-up of 35 months. Cardiac pacing was needed in 46% patients: 14% had complete pacing dependency, 17% had high degree AV block, while 15% had a high ventricular pacing rate (>80%). No pre- or per-operative variables could predict cardiac pacing requirement. Post-operatively, a spontaneous heart rate >70 bpm (P = 0.02) and the presence of narrow QRS (P = 0.03) were significantly associated with a lower risk of cardiac pacing requirement. Complications related to epicardial pacemaker were documented in 2 (2.5%) patients.

CONCLUSIONS

After TVR, cardiac pacing was needed in 46% of patients for post-operative atrioventricular conduction disorders. This high incidence associated with an acceptable safety profile supports a prophylactic epicardial pacing strategy for the patients undergoing TVR.

Heart transplantation as a rescue strategy for patients with refractory electrical storm

AIMS

Heart transplantation (HT) can be proposed as a therapeutic strategy for patients with severe refractory electrical storm (ES). Data in the literature are scarce and based on case reports. We aimed at determining the characteristics and survival of patients transplanted for refractory ES.

METHODS AND RESULTS

Patients registered on HT waiting list during the following days after ES and eventually transplanted, from 2010 to 2021, were retrospectively included in 11 French centres. The primary endpoint was in-hospital mortality. Forty-five patients were included [82% men; 55.0 (47.8-59.3) years old; 42.2% and 26.7% non-ischaemic dilated or ischaemic cardiomyopathies, respectively]. Among them, 42 (93.3%) received amiodarone, 29 received (64.4%) beta blockers, 19 (42.2%) required deep sedation, 22 had (48.9%) mechanical circulatory support, and 9 (20.0%) had radiofrequency catheter ablation. Twenty-two patients (62%) were in cardiogenic shock. Inscription on wait list and transplantation occurred 3.0 (1.0-5.0) days and 9.0 (4.0-14.0) days after ES onset, respectively. After transplantation, 20 patients (44.4%) needed immediate haemodynamic support by extracorporeal membrane oxygenation (ECMO). In-hospital mortality rate was 28.9%. Predictors of in-hospital mortality were serum creatinine/urea levels, need for immediate post-operative ECMO support, post-operative complications, and surgical re-interventions. One-year survival was 68.9%.

CONCLUSION

Electrical storm is a rare indication of HT but may be lifesaving in those patients presenting intractable arrhythmias despite usual care. Most patients can be safely discharged from hospital, although post-operative mortality remains substantial in this context of emergency transplantation. Larger studies are warranted to precisely determine those patients at higher risk of in-hospital mortality.

Automatic digitization of paper electrocardiograms - A systematic review

The digitization of electrocardiogram paper records is an essential step to preserve and analyze cardiac data. This digitization process is not flawless as it involves several challenges, such as skew correction, binarization, and signal extraction. Various approaches have been proposed to address these challenges and recent studies have introduced innovative solutions, such as deep learning models and automation processes. Although existing approaches have shown promising results, there is a lack of common databases and metrics where authors could evaluate and compare their methods. Furthermore, the limited accessibility of code or software hinders the comparison process. Overall, while digitization of paper ECG recordings is important in advancing cardiology research, additional efforts are needed to standardize the evaluation process while improving code accessibility. This article provides a systematic review of this process.

Continuous Bayesian variant interpretation accounts for incomplete penetrance among Mendelian cardiac channelopathies

PURPOSE

The congenital Long QT Syndrome (LQTS) and Brugada Syndrome (BrS) are Mendelian autosomal dominant diseases that frequently precipitate fatal cardiac arrhythmias. Incomplete penetrance is a barrier to clinical management of heterozygotes harboring variants in the major implicated disease genes KCNQ1, KCNH2, and SCN5A. We apply and evaluate a Bayesian penetrance estimation strategy that accounts for this phenomenon.

METHODS

We generated Bayesian penetrance models for KCNQ1-LQT1 and SCN5A-LQT3 using variant-specific features and clinical data from the literature, international arrhythmia genetic centers, and population controls. We analyzed the distribution of posterior penetrance estimates across 4 genotype-phenotype relationships and compared continuous estimates with ClinVar annotations. Posterior estimates were mapped onto protein structure.

RESULTS

Bayesian penetrance estimates of KCNQ1-LQT1 and SCN5A-LQT3 are empirically equivalent to 10 and 5 clinically phenotype heterozygotes, respectively. Posterior penetrance estimates were bimodal for KCNQ1-LQT1 and KCNH2-LQT2, with a higher fraction of missense variants with high penetrance among KCNQ1 variants. There was a wide distribution of variant penetrance estimates among identical ClinVar categories. Structural mapping revealed heterogeneity among "hot spot" regions and featured high penetrance estimates for KCNQ1 variants in contact with calmodulin and the S6 domain.

CONCLUSIONS

Bayesian penetrance estimates provide a continuous framework for variant interpretation.

Idiopathic ventricular fibrillation associated with long-coupled Purkinje ectopy

INTRODUCTION

Idiopathic ventricular fibrillation (IVF) is mainly associated with and triggered by short-coupled (R-on-T) ventricular ectopics. However, little is known about the risk of VF associated with long-coupled premature ventricular complexes (LCPVCs).

OBJECTIVE

To examine the prevalence and characteristics of IVF patients presenting with LCPVCs.

METHODS

Consecutive patients with IVF and PVCs from five arrhythmia referral centers were reviewed. We included patients presenting LCPVCs, defined as PVCs falling after the end of the T wave, with a normal QTc interval. We evaluated demographics, medical history, and clinical circumstances associated with PVCs and VF episodes. The origin of PVCs was determined by invasive mapping.

RESULTS

Seventy-nine patients with IVF were reviewed. Among them, 12 (15.2%) met the inclusion criteria (8 women, age 36 ± 14 years). Eleven patients had documented LCPVCs initiating repetitive PVCs or sustained VF, whereas 1 had only documented isolated PVCs. In 10 of 12 patients, PVCs were recorded showing both long and short coupling intervals of 418 ± 46 and 304 ± 33 ms, respectively. Mapping showed that PVCs originated from the left Purkinje in 10 patients, from the right Purkinje in 1 patient, and both in 1 patient. Compared to other patients from the initial cohort, IVF with LCPVCs was associated with a left-sided origin of PVCs (92% in long-coupled IVF vs. 46% of left Purkinje PVCs in short-coupled IVF, p = .004).

CONCLUSION

Long-coupled fascicular PVCs, traditionally recognized as benign, can be associated with IVF in a subset of patients. They can induce IVF by themselves or in association with short-coupled PVCs.

Rapid ventricular tachycardia in patients with tetralogy of Fallot and implantable cardioverter-defibrillator: Insights from the DAI-T4F nationwide registry

BACKGROUND

In repaired tetralogy of Fallot (TOF), little is known about characteristics of patients with rapid ventricular tachycardia (VT). Also, whether patients with a first episode of nonrapid VT may subsequently develop rapid VT or ventricular fibrillation (VF) has not been addressed.

OBJECTIVES

The objectives of this study were to compare patients with rapid VT/VF with those with nonrapid VT and to assess the evolution of VT cycle lengths (VTCLs) overtime.

METHODS

Data were analyzed from a nationwide registry including all patients with TOF and implantable cardioverter-defibrillator (ICD) since 2000. Patients with ≥1 VT episode with VTCL ≤250 ms (240 beats/min) formed the rapid VT/VF group.

RESULTS

Of 144 patients (mean age 42.0 ± 12.7 years; 104 [72%] men), 61 (42%) had at least 1 VT/VF episode, including 28 patients with rapid VT/VF (46%), during a median follow-up of 6.3 years (interquartile range 2.2-10.3 years). Compared with patients in the nonrapid VT group, those in the rapid VT/VF group were significantly younger at ICD implantation (35.2 ± 12.6 years vs 41.5 ± 11.2 years; P = .04), had more frequently a history of cardiac arrest (8 [29%] vs 2 [6%]; P = .02), less frequently a history of atrial arrhythmia (11 [42%] vs 22 [69%]; P = .004), and higher right ventricular ejection fraction (43.3% ± 10.3% vs 36.6% ± 11.2%; P = .04). The median VTCL of VT/VF episodes was 325 ms (interquartile range 235-429 ms). None of the patients with a first documented nonrapid VT episode had rapid VT/VF during follow-up.

CONCLUSION

Patients with TOF and rapid VT/VF had distinct clinical characteristics. The relatively low variation of VTCL over time suggests a room for catheter ablation without a backup ICD in selected patients with well-tolerated VT.

Differential Effect of Targeted Temperature Management Between 32 °C and 36 °C Following Cardiac Arrest According to Initial Severity of Illness: Insights From Two International Data Sets

BACKGROUND

Recent guidelines have emphasized actively avoiding fever to improve outcomes in patients who are comatose following resuscitation from cardiac arrest (ie, out-of-hospital cardiac arrest). However, whether targeted temperature management between 32 °C and 36 °C (TTM32-36) can improve neurologic outcome in some patients remains debated.

RESEARCH QUESTION

Is there an association between the use of TTM32-36 and outcome according to severity assessed at ICU admission using a previously derived risk score?

STUDY DESIGN AND METHODS

Data prospectively collected in the Sudden Death Expertise Center (SDEC) registry (France) between May 2011 and December 2017 and in the Resuscitation Outcomes Consortium Continuous Chest Compressions (ROC-CCC) trial (United States and Canada) between June 2011 and May 2015 were used for this study. Severity at ICU admission was assessed through a modified version of the Cardiac Arrest Hospital Prognosis (mCAHP) score, divided into tertiles of severity. The study explored associations between TTM32-36 and favorable neurologic status at hospital discharge by using multiple logistic regression as well as in tertiles of severity for each data set.

RESULTS

A total of 2,723 patients were analyzed in the SDEC data set and 4,202 patients in the ROC-CCC data set. A favorable neurologic status at hospital discharge occurred in 728 (27%) patients in the French data set and in 1,239 (29%) patients in the North American data set. Among the French data set, TTM32-36 was independently associated with better neurologic outcome in the tertile of patients with low (adjusted OR, 1.63; 95% CI, 1.15-2.30; P = .006) and high (adjusted OR, 1.94; 95% CI, 1.06-3.54; P = .030) severity according to mCAHP at ICU admission. Similar results were observed in the North American data set (adjusted ORs of 1.36 [95% CI, 1.05-1.75; P = .020] and 2.42 [95% CI, 1.38-4.24; P = .002], respectively). No association was observed between TTM32-36 and outcome in the moderate groups of the two data sets.

INTERPRETATION

TTM32-36 was significantly associated with a better outcome in patients with low and high severity at ICU admission assessed according to the mCAHP score. Further studies are needed to evaluate individualized temperature control following out-of-hospital cardiac arrest.

Electrical cardioversion of atrial arrhythmias with cardiac amyloidosis in the era of direct oral anticogulants

AIMS

Atrial fibrillation (AF)/atrial flutter is common during cardiac amyloidosis (CA). Electrical cardioversion (EC) is a strategy to restore sinus rhythm (SR). However, left atrial thrombus (LAT) represents a contraindication for EC. CA patients with AF/atrial flutter have a high prevalence of LAT. We aimed to evaluate EC characteristics, LAT prevalence and risk factors, and AF/atrial flutter outcome in CA patients undergoing EC, predominantly treated with direct oral anticoagulants (DOACs).

METHODS AND RESULTS

All patients with CA and AF/atrial flutter referred for the first time to our national referral centre of amyloidosis for EC from June 2017 to February 2021 were included in this study. In total, 66 patients (median age 74.5 [70;80.75] years, 67% male) were included with anticoagulation consisted of DOAC in 74% of cases. All patients underwent cardiac imaging before EC to rule out LAT. EC was cancelled due to LAT in 14% of cases. Complete thrombus resolution was observed in only 17% of cases. The two independent parameters associated with LAT were creatinine [hazard ratio (HR) = 1.01; confidence interval (CI) = 1.00-1.03, P = 0.036] and the use of antiplatelet agents (HR = 13.47; CI = 1.85-98.02). EC acute success rate was 88%, and we observed no complication after EC. With 64% of patients under amiodarone, AF/atrial flutter recurrence rate following EC was 51% after a mean follow-up of 30 ± 27 months.

CONCLUSIONS

Left atrial thrombus was observed in 14% of CA patients listed for EC and mainly treated with DOAC. The acute EC success rate was high with no complication. The long-term EC success rate was acceptable (49%).

Characteristics and factors associated to patients discharging from hospital without an implantable cardioverter defibrillator after out-of-hospital cardiac arrest

AIMS

Guidelines recommend that in the absence of reversible cause for sudden cardiac arrest (SCA), implantable cardioverter defibrillator (ICD) should be performed to prevent further fatal event. We sought to describe the frequency and characteristics of patients discharged from the hospital without ICD after the SCA in the daily practice.

METHODS AND RESULTS

From 2011 to 2018, all SCAs related to a cardiac cause admitted alive across the 48 hospitals of Great Paris Area were prospectively enrolled. Two investigators thoroughly reviewed each medical report to ensure accuracy of the assigned diagnosis towards identifying the cause of SCA and ICD implantation. Out of the 4314 SCA admitted alive at hospital admission, 1064 cardiac-related SCA survivors were discharged alive from hospital, including 356 patients (33.5%) with an ICD and 708 (66.5%) without. The principal underlying cause of SCA among those discharged without an ICD was acute coronary syndrome (ACS; 602, 85%), chronic coronary artery disease (41, 5.8%), structural non-ischaemic heart disease (48, 6.8%), and non-structural heart disease (17, 2.4%). Among ACS-related SCA, 93.8% (602/642) discharged without an ICD. The unique factor associated with non-ICD implantation in the setting of ACS was immediate coronary angioplasty (odds ratio 4.22, 95% confidence interval 1.86-9.30, P < 0.001).

CONCLUSION

Two-thirds of SCA survivors were discharged without an ICD, mainly in the setting of ACS. The unique factor associated with non-ICD implantation among ACS was immediate coronary angioplasty emphasizing the fact that ACS definition must be precise since associated with ICD implantation or not.

Lack of Early Etiologic Investigations in Young Sudden Cardiac Death

BACKGROUND

Since majority of sudden cardiac arrest (SCA) victims die in the intensive care unit (ICU), early etiologic investigations may improve understanding of SCA and targeted prevention.

METHODS

In this prospective, population-based registry all SCA admitted alive across the 48 hospitals of the Paris area were enrolled. We investigated the extent of early etiologic work-up among young SCD cases (<45 years) eventually dying within the ICU.

RESULTS

From May 2011 to May 2018, 4,314 SCA patients were admitted alive. Among them, 3,044 died in ICU, including 484 (15.9%) young patients. SCA etiology was established in 233 (48.1%) and remained unexplained in 251 (51.9%). Among unexplained (compared to explained) cases, coronary angiography (17.9 vs. 49.4%, P<0.001), computed tomography scan (24.7 vs. 46.8%, P<0.001) and trans-thoracic echocardiography (31.1 vs. 56.7%, P<0.001) were less frequently performed. Only 22 (8.8%) patients with unexplained SCD underwent all three investigations. SCDs with unexplained status decreased significantly over the 7 years of the study period (from 62.9 to 35.2%, P=0.005). While specialized TTE and CT scan performances have increased significantly, performance of early coronary angiography did not change. Autopsy, genetic analysis and family screening were performed in only 48 (9.9%), 5 (1.0%) and 14 cases (2.9%) respectively.

CONCLUSIONS

More than half of young SCD dying in ICU remained etiologically unexplained; this was associated with a lack of early investigations. Improving early diagnosis may enhance both SCA understanding and prevention, including for relatives. Failure to identify familial conditions may result in other preventable deaths within these families.

ECG descriptors of ventricular repolarization are associated with cardiac events in a gene-specific manner in long QT syndrome patients

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): Assistance Publiques Hôpitaux de Paris (APHP)

Background

Congenital long QT syndrome (LQTS) is still associated with syncope and a risk of sudden cardiac death despite the dramatic reduction in mortality associated with beta-blocker therapy. Current risk stratification tools are imperfect.

Objective

To assess the contribution of automated scalar ECG descriptors of ventricular repolarization for arrrhythmic risk stratification in genotyped LQTS patients.

Methods

Patients with genotyped type 1, 2 or 3 LQTS with at least 1 digital ECG recording have been included in the study. History at diagnosis, and follow-up data were collected. Cardiac events included syncope, aborted cardiac arrest, appropriate implantable cardioverter-defibrillator therapy in VF zone, and sudden death.

ECG were analyzed using the BRAVO algorithm embedded in the CalECG software, version 4.1.0. QT interval duration was manually checked but ECG descriptors of Ventricular Repolarization were fully automatic.

Multivariate cox regression analysis were performed to identify parameters associated with cardiac events.

Results

467 patients (58% female, median age at diagnosis=25, LQT1,2,3 54%, 39%, 7%) were followed-up during 15.2±9.2 years. Rate of cardiac event was 1.2/100 patients-year before diagnosis and 0.9/100 patients-year during follow-up.

QTc duration was associated with the occurrence of cardiac events in the whole study population (HR=1.01 95%CI 1.0-1.01, p=0.03). Ventricular repolarization parameters associated with cardiac events were different according to LQTS type. Cardiac events were associated with increased time to accumulate 50% of T-wave energy (HR=1.53 95%CI 1.04-2.26, p=0.03) in LQT1 but with a decrease in T-wave slopes (ascending slope HR=0.63 95%CI 0.17-0.75, p&lt;0.01) in type 2 LQTS patients. QTc duration was not independently associated with cardiac events in genotype specific multivariate models.

Conclusions

T-wave morphology parameters are associated with cardiac events in a gene-specific manner. Change in T-wave symmetry and T-wave flattening are associated with cardiac events in type 1 and type 2 LQTS respectively. The descriptors of ventricular repolarization are promising parameters or risk stratification beyond QTc duration in LQTS patients.

An International Multi-Center Cohort Study on β-blockers for the Treatment of Symptomatic Children with Catecholaminergic Polymorphic Ventricular Tachycardia

Background: Symptomatic children with catecholaminergic polymorphic ventricular tachycardia (CPVT) are at risk for recurrent arrhythmic events. Beta-blockers (BBs) decrease this risk, but studies comparing individual BBs in sizeable cohorts are lacking. We aimed to assess the association between risk for arrhythmic events and type of BB in a large cohort of symptomatic children with CPVT. Methods: From two international registries of patients with CPVT, RYR2 variant-carrying symptomatic children (defined as syncope or sudden cardiac arrest prior to BB initiation and age at start of BB therapy <18 years), treated with a BB were included. Cox-regression analyses with time-dependent covariates for BB and potential confounders were used to assess the hazard ratio (HR). The primary outcome was the first occurrence of sudden cardiac death, sudden cardiac arrest, appropriate implantable cardioverter-defibrillator shock, or syncope. The secondary outcome was the first occurrence of any of the primary outcomes except syncope. Results: We included 329 patients (median age at diagnosis 12 [interquartile range, 7-15] years, 35% females). Ninety-nine (30.1%) patients experienced the primary and 74 (22.5%) experienced the secondary outcome during a median follow-up of 6.7 [interquartile range, 2.8-12.5] years. Two-hundred sixteen patients (66.0%) used a non-selective BB (predominantly nadolol [n=140] or propranolol [n=70]) and 111 (33.7%) used a β1-selective BB (predominantly atenolol [n=51], metoprolol [n=33], or bisoprolol [n=19]) as initial BB. Baseline characteristics did not differ. The HR for both the primary and secondary outcomes were higher for β1-selective compared with non-selective BBs (HR, 2.04 95% CI, 1.31-3.17; and HR, 1.99; 95% CI, 1.20-3.30, respectively). When assessed separately, the HR for the primary outcome was higher for atenolol (HR, 2.68; 95% CI, 1.44-4.99), bisoprolol (HR, 3.24; 95% CI, 1.47-7.18), and metoprolol (HR, 2.18; 95% CI, 1.08-4.40) compared with nadolol, but did not differ from propranolol. The HR of the secondary outcome was only higher in atenolol compared with nadolol (HR, 2.68; 95% CI, 1.30-5.55). Conclusions: B1-selective BBs were associated with a significantly higher risk for arrhythmic events in symptomatic children with CPVT compared with non-selective BBs, specifically nadolol. Nadolol, or propranolol if nadolol is unavailable, should be the preferred BB for treating symptomatic children with CPVT.

Capacities of atrial fibrillation detection after stroke: a French nationwide survey

Background

Atrial fibrillation (AFib) is a major contributor to recurrent but preventable ischemic Stroke (IS)/TIA. However, majority of stroke patients suffer from paroxysmal asymptomatic AFib, which implies stroke health system to implement accurate AFib detection strategies to large scale population. Current practices of AFib screening methods provided by Stroke Units (SU) organization and network in France are currently unknown and uncovered by dedicated guidelines.

Purpose

To assess the methodology of Afib screening in French SU.

Methods

A French Nationwide survey was led (September-November 2020) with on-line structured questionnaires sent to individual targeted stroke-physicians (SP) and heads of SU in France.We analyzed qualitative and quantitative availability and current use of AFib detection tools during acute inhospital and outpatient subacute and chronic post-IS phases.

Results

67% of 140 heads of SU and 33% of SP responded across all continental and overseas French regions.Main clinical characteristics that lead to search Afib are: TIA/IS recurrence under antiplatelet therapy (97%), patient's age (74%), proximal occlusion of a major cerebral artery (72%). Afib is highly suspected when there is: recent brain IS in multiple vascular territories (100%), previous IS in another vascular territory (98%), left atrial enlargement (96%), burst of supraventricular tachycardia &lt;30s (94%). In-hospital cardiac monitoring is considered to be mandatory by 90% of SU teams but only 1/3 of those possess telemetry out of intensive care unit. Outpatient cardiac monitoring is considered of major interest/necessary by 100% of SP. When first line 24-hour Holter monitor is normal and Afib is highly suspected, 75% of the SP required outpatient noninvasive monitoring (NIM) for at least 7 days and more than half required insertable cardiac monitor (ISC). ISC are implanted each year by SU for &lt;10 patients in 44% and &lt;50 patients in 94%. The delay IS-ICM implantation is &lt;1 month in 10%, 1–3 months in 52%, 3–6 months in 29% and &gt;6 months in 9%. Accessibility to outpatient monitoring modalities is graded: fairly easy for 24/48h-Holter (85%) and ISC (68%); rather difficult/impossible for 3–7 days NIM (51%), 8–21 days NIM (75%) or e-ECG tools (99%). Main obstacles to monitoring abilities development in SU were lack of: manpower (80%), efficient network with cardiologists (56%), familiarity of techniques (42%); and technical equipment cost (44%). 96.5% of SU teams deem necessary practice decision support flowchart with cardiologist partnership but 19% use for it.

Conclusion

The survey raises concern about lack of a systematic strategy and shortcomings for Afib detection capacities. These results are a call to establish practice-guidelines and to promote an improvement plan for AFib detection (selection of the patients, tools and prioritization of the exams) after TIA/IS in France which will require a strong collaboration between neurologists and cardiologists.

Funding Acknowledgement

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): BMS-Pfizer

Deep learning analysis of electrocardiogram for risk prediction of drug-induced arrhythmias and diagnosis of long QT syndrome

AIMS

Congenital long-QT syndromes (cLQTS) or drug-induced long-QT syndromes (diLQTS) can cause torsade de pointes (TdP), a life-threatening ventricular arrhythmia. The current strategy for the identification of drugs at the high risk of TdP relies on measuring the QT interval corrected for heart rate (QTc) on the electrocardiogram (ECG). However, QTc has a low positive predictive value.

METHODS AND RESULTS

We used convolutional neural network (CNN) models to quantify ECG alterations induced by sotalol, an IKr blocker associated with TdP, aiming to provide new tools (CNN models) to enhance the prediction of drug-induced TdP (diTdP) and diagnosis of cLQTS. Tested CNN models used single or multiple 10-s recordings/patient using 8 leads or single leads in various cohorts: 1029 healthy subjects before and after sotalol intake (n = 14 135 ECGs); 487 cLQTS patients (n = 1083 ECGs: 560 type 1, 456 type 2, 67 type 3); and 48 patients with diTdP (n = 1105 ECGs, with 147 obtained within 48 h of a diTdP episode). CNN models outperformed models using QTc to identify exposure to sotalol [area under the receiver operating characteristic curve (ROC-AUC) = 0.98 vs. 0.72, P ≤ 0.001]. CNN models had higher ROC-AUC using multiple vs. single 10-s ECG (P ≤ 0.001). Performances were comparable for 8-lead vs. single-lead models. CNN models predicting sotalol exposure also accurately detected the presence and type of cLQTS vs. healthy controls, particularly for cLQT2 (AUC-ROC = 0.9) and were greatest shortly after a diTdP event and declining over time (P ≤ 0.001), after controlling for QTc and intake of culprit drugs. ECG segment analysis identified the J-Tpeak interval as the best discriminator of sotalol intake.

CONCLUSION

CNN models applied to ECGs outperform QTc measurements to identify exposure to drugs altering the QT interval, congenital LQTS, and are greatest shortly after a diTdP episode.

Computerized automated algorithm-based analyses of digitized paper ECGs in Brugada syndrome

BACKGROUND

Brugada syndrome is a rare inherited arrhythmic syndrome with a coved type 1 ST-segment elevation on ECG and an increased risk of sudden death. Many studies have evaluated risk stratification performance based on ECG-derived parameters. However, since historical Brugada patient cohorts included mostly paper ECGs, most studies have been based on manual ECG parameter measurements. We hypothesized that it would be possible to run automated algorithm-based analysis of paper ECGs. We aimed: 1) to validate the digitization process for paper ECGs in Brugada patients; and 2) to quantify the acute class I antiarrhythmic drug effect on relevant ECG parameters in Brugada syndrome.

METHODS

A total of 176 patients (30% female, 43 ± 13 years old) with induced type 1 Brugada syndrome ECG were included in the study. All of the patients had paper ECGs before and during class I antiarrhythmic drug challenge. Twenty patients also had a digital ECG, in whom printouts were used to validate the digitization process. Paper ECGs were scanned and then digitized using ECGScan software, version 3.4.0 (AMPS, LLC, New York, NY, USA) to obtain FDA HL7 XML format ECGs. Measurements were automatically performed using the Bravo (AMPS, LLC, New York, NY, USA) and Glasgow algorithms.

RESULTS

ECG parameters obtained from digital and digitized ECGs were closely correlated (r = 0.96 ± 0.07, R² = 0.93 ± 0.12). Class I antiarrhythmic drugs significantly increased the global QRS duration (from 113 ± 20 to 138 ± 23, p < 0.0001). On lead V2, class I antiarrhythmic drugs increased ST-segment elevation (from 110 ± 84 to 338 ± 227 μV, p < 0.0001), decreased the ST slope (from 14.9 ± 23.3 to -27.4 ± 28.5, p < 0.0001) and increased the TpTe interval (from 88 ± 18 to 104 ± 33, p < 0.0001).

CONCLUSIONS

Automated algorithm-based measurements of depolarization and repolarization parameters from digitized paper ECGs are reliable and could quantify the acute effects of class 1 antiarrhythmic drug challenge in Brugada patients. Our results support using computerized automated algorithm-based analyses from digitized paper ECGs to establish risk stratification decision trees in Brugada syndrome.

Wearable cardioverter-defibrillator in patients with a transient risk of sudden cardiac death: the WEARIT-France cohort study

Aims 

We aimed to provide contemporary real-world data on wearable cardioverter-defibrillator (WCD) use, not only in terms of effectiveness and safety but also compliance and acceptability.

Methods and results 

Across 88 French centres, the WEARIT-France study enrolled retrospectively patients who used the WCD between May 2014 and December 2016, and prospectively all patients equipped for WCD therapy between January 2017 and March 2018. All patients received systematic education session through a standardized programme across France at the time of initiation of WCD therapy and were systematically enrolled in the LifeVest Network remote services. Overall, 1157 patients were included (mean age 60 ± 12 years, 16% women; 46% prospectively): 82.1% with ischaemic cardiomyopathy, 10.3% after implantable cardioverter-defibrillator explant, and 7.6% before heart transplantation. Median WCD usage period was 62 (37–97) days. Median daily wear time of WCD was 23.4 (22.2–23.8) h. In multivariate analysis, younger age was associated with lower compliance [adjusted odds ratio (OR) 0.97, 95% confidence interval (CI) 0.95–0.99, P < 0.01]. A total of 18 participants (1.6%) received at least one appropriate shock, giving an incidence of appropriate therapy of 7.2 per 100 patient-years. Patient-response button allowed the shock to be aborted in 35.7% of well-tolerated sustained ventricular arrhythmias and in 95.4% of inappropriate ventricular arrhythmia detection, finally resulting in an inappropriate therapy in eight patients (0.7%).

Conclusion

Our real-life findings reinforce previous studies on the efficacy and safety of the WCD in the setting of transient high-risk group in selected patients. Moreover, they emphasize the fact that when prescribed appropriately, in concert with adequate patient education and dedicated follow-up using specific remote monitoring system, compliance with WCD is high and the device well-tolerated by the patient.

Estimating the Posttest Probability of Long QT Syndrome Diagnosis for Rare KCNH2 Variants

BACKGROUND

The proliferation of genetic profiling has revealed many associations between genetic variations and disease. However, large-scale phenotyping efforts in largely healthy populations, coupled with DNA sequencing, suggest variants currently annotated as pathogenic are more common in healthy populations than previously thought. In addition, novel and rare variants are frequently observed in genes associated with disease both in healthy individuals and those under suspicion of disease. This raises the question of whether these variants can be useful predictors of disease. To answer this question, we assessed the degree to which the presence of a variant in the cardiac potassium channel gene KCNH2 was diagnostically predictive for the autosomal dominant long QT syndrome.

METHODS

We estimated the probability of a long QT diagnosis given the presence of each KCNH2 variant using Bayesian methods that incorporated variant features such as changes in variant function, protein structure, and in silico predictions. We call this estimate the posttest probability of disease. Our method was applied to over 4000 individuals heterozygous for 871 missense or in-frame insertion/deletion variants in KCNH2 and validated against a separate international cohort of 933 individuals heterozygous for 266 missense or in-frame insertion/deletion variants.

RESULTS

Our method was well-calibrated for the observed fraction of heterozygotes diagnosed with long QT syndrome. Heuristically, we found that the innate diagnostic information one learns about a variant from 3-dimensional variant location, in vitro functional data, and in silico predictors is equivalent to the diagnostic information one learns about that same variant by clinically phenotyping 10 heterozygotes. Most importantly, these data can be obtained in the absence of any clinical observations.

CONCLUSIONS

We show how variant-specific features can inform a prior probability of disease for rare variants even in the absence of clinically phenotyped heterozygotes.

Sex differences in the origin of Purkinje ectopy-initiated idiopathic ventricular fibrillation

BACKGROUND

Purkinje ectopics (PurkEs) are major triggers of idiopathic ventricular fibrillation (VF). Identifying clinical factors associated with specific PurkE characteristics could yield insights into the mechanisms of Purkinje-mediated arrhythmogenicity.

OBJECTIVE

The purpose of this study was to examine the associations of clinical, environmental, and genetic factors with PurkE origin in patients with PurkE-initiated idiopathic VF.

METHODS

Consecutive patients with PurkE-initiated idiopathic VF from 4 arrhythmia referral centers were included. We evaluated demographic characteristics, medical history, clinical circumstances associated with index VF events, and electrophysiological characteristics of PurkEs. An electrophysiology study was performed in most patients to confirm the Purkinje origin.

RESULTS

Eighty-three patients were included (mean age 38 ± 14 years; 44 [53%] women), of whom 32 had a history of syncope. Forty-four patients had VF at rest. PurkEs originated from the right ventricle (RV) in 41 patients (49%), from the left ventricle (LV) in 36 (44%), and from both ventricles in 6 (7%). Seasonal and circadian distributions of VF episodes were similar according to PurkE origin. The clinical characteristics of patients with RV vs LV PurkE origins were similar, except for sex. RV PurkEs were more frequent in men than in women (76% vs 24%), whereas LV and biventricular PurkEs were more frequent in women (81% vs 19% and 83% vs 17%, respectively) (P < .0001).

CONCLUSION

PurkEs triggering idiopathic VF originate dominantly from the RV in men and from the LV or both ventricles in women, adding to other sex-related arrhythmias such as Brugada syndrome or long QT syndrome. Sex-based factors influencing Purkinje arrhythmogenicity warrant investigation.

Prediction of ventricular arrhythmias in patients with a spontaneous Brugada type 1 pattern: the key is in the electrocardiogram

AIMS

There is currently no reliable tool to quantify the risks of ventricular fibrillation or sudden cardiac arrest (VF/SCA) in patients with spontaneous Brugada type 1 pattern (BrT1). Previous studies showed that electrocardiographic (ECG) markers of depolarization or repolarization disorders might indicate elevated risk. We aimed to design a VF/SCA risk prediction model based on ECG analyses for adult patients with spontaneous BrT1.

METHODS AND RESULTS

This retrospective multicentre international study analysed ECG data from 115 patients (mean age 45.1 ± 12.8 years, 105 males) with spontaneous BrT1. Of these, 45 patients had experienced VF/SCA and 70 patients did not experience VF/SCA. Among 10 ECG markers, a univariate analysis showed significant associations between VF/SCA and maximum corrected Tpeak-Tend intervals ≥100 ms in precordial leads (LMaxTpec) (P < 0.001), BrT1 in a peripheral lead (pT1) (P = 0.004), early repolarization in inferolateral leads (ER) (P < 0.001), and QRS duration ≥120 ms in lead V2 (P = 0.002). The Cox multivariate analysis revealed four predictors of VF/SCA: the LMaxTpec [hazard ratio (HR) 8.3, 95% confidence interval (CI) 2.4-28.5; P < 0.001], LMaxTpec + ER (HR 14.9, 95% CI 4.2-53.1; P < 0.001), LMaxTpec + pT1 (HR 17.2, 95% CI 4.1-72; P < 0.001), and LMaxTpec + pT1 + ER (HR 23.5, 95% CI 6-93; P < 0.001). Our multidimensional penalized spline model predicted the 1-year risk of VF/SCA, based on age and these markers.

CONCLUSION

LMaxTpec and its association with pT1 and/or ER indicated elevated VF/SCA risk in adult patients with spontaneous BrT1. We successfully developed a simple risk prediction model based on age and these ECG markers.

Predictive value of premature atrial complex characteristics in pulmonary vein isolation for patients with paroxysmal atrial fibrillation

BACKGROUND

Premature atrial complexes from pulmonary veins are the main triggers for atrial fibrillation in the early stages. Thus, pulmonary vein isolation is the cornerstone of catheter ablation for paroxysmal atrial fibrillation. However, the success rate remains perfectible.

AIM

To assess whether premature atrial complex characteristics before catheter ablation can predict pulmonary vein isolation success in paroxysmal atrial fibrillation.

METHODS

We investigated consecutive patients who underwent catheter ablation for paroxysmal atrial fibrillation from January 2013 to April 2017 in two French centres. Patients were included if they were treated with pulmonary vein isolation alone, and had 24-hour Holter electrocardiogram data before catheter ablation available and a follow-up of≥6 months. Catheter ablation success was defined as freedom from any sustained atrial arrhythmia recurrence after a 3-month blanking period following catheter ablation.

RESULTS

One hundred and three patients were included; all had an acute successful pulmonary vein isolation procedure, and 34 (33%) had atrial arrhythmia recurrences during a mean follow-up of 30±15 months (group 1). Patients in group 1 presented a longer history of atrial fibrillation (71.9±65.8 vs. 42.9±48.4 months; P=0.008) compared with those who were "free from arrhythmia" (group 2). Importantly, the daily number of premature atrial complexes before catheter ablation was significantly lower in group 1 (498±1413 vs. 1493±3366 in group 2; P=0.028). A daily premature atrial complex cut-off number of<670 predicted recurrences after pulmonary vein isolation (41.1% vs. 13.3%; sensitivity 88.2%; specificity 37.7%; area under the curve 0.635; P=0.017), and was the only independent predictive criterion in the multivariable analysis (4-fold increased risk).

CONCLUSION

Preprocedural premature atrial complex analysis on 24-hour Holter electrocardiogram in paroxysmal atrial fibrillation may improve patient selection for pulmonary vein isolation.

Electrocardiographic and echocardiographic abnormalities associated with mitral valve prolapse in patients with Marfan syndrome

Introduction

Marfan syndrome (MFS) is responsible for cardiovascular disorders such as aortic aneurism and mitral valve prolapse (MVP).

A malignant MVP phenotype combining clinical, electrical and morphological features has been described in symptomatic patients who have experienced sudden cardiac death or complex ventricular arrhythmias.

We have taken advantage of the high prevalence of MVP in MFS patient to study the clinical, electrical and echocardiographic abnormalities associated with MVP.

Purpose

The aim of this study is to describe the clinical, electrical and morphological cardiac abnormalities associated with MVP in a cohort of MFS patients with FBN1 mutations with a high prevalence of MVP and who did not suffer from severe ventricular arrhythmias.

Methods

All consecutive patients coming to the National Reference Center for Marfan syndrome were evaluated prospectively i.e. clinical examination, 12-lead electrocardiogram, standard transthoracic echocardiography study and molecular genetic screening.

Results

352 consecutive patients were included from April 2015 to October 2016 [250 FBN1 mutation carriers (MFS) and 102 healthy relatives (HR)]. None of the patients had a history of sudden cardiac death or complex ventricular arrhythmia.

MFS vs HR: MFS patients were younger (33 vs 41yo p&lt;0.001) and 2/3 were women in both groups. In the MFS group, abnormal T waves repolarization in lateral leads were more common [172 MFS (70.2%) vs. 87 HR (86.14%) p&lt;0,0012], as was MVP [38.37% vs 1.96%; p&lt;0,0001], and diastolic hypertrophy of the basal segment of the inferolateral wall (thickness &gt;11mm) [22.31% vs. 9.18%; p&lt;0.0001].

In MFS, MVP affected either one valve (21.22%), or both (17.14%), and was not associated with electric abnormalities. However, diastolic basal inferolateral wall hypertrophy was associated with mitral valve prolapse (p&lt;0,0001), QTc interval prolongation (p&lt;0.0229), abnormal T waves repolarization in the inferior leads (p=0.004), and higher aortic Z-Score (p=0.274).

Conclusion

In MFS patients, the prevalence of MVP is high and no significant association between MVP and electrical abnormalities was found. In contrast, basal inferolateral wall hypertrophy is associated with MVP and repolarization disorders in inferior leads and QTc interval prolongation, i.e, electrocardiographic abnormalities described in malignant MVP.

QTc and basal inferolateral hypertrophy

Funding Acknowledgement

Type of funding source: None

Prognostic significance of a low T/R ratio in Brugada syndrome

OBJECTIVES

To determine the prognostic value of a low T/R ratio, defined as the amplitude ratio between the T waves and the R waves, in patients (pts) with a spontaneous type-1 Brugada pattern (SBT1).

BACKGROUND

Abnormalities of myocardial repolarization may play a key role in the initiation of ventricular fibrillation (VF) in Brugada syndrome (BrS). Recent studies have shown that the height of the T waves and the T/R ratio are inversely proportional to sudden cardiac arrest (SCA) risk in early repolarization syndrome and hypertrophic cardiomyopathy.

METHODS

In an international retrospective study, we reviewed 115 pts. (105 males, 91.3%). 45 had VF and/or SCA (38.7 ± 11.5 years old, all males), while 70 (49.3 ± 12.0 years, 10 women) remained free of ventricular arrhythmia. 6 ECG markers plus the T/R ratio in leads V5 & II were studied.

RESULTS

The T/R ratio among leads II & V5 was significantly lower in the VF/SCA group (0.24 [0.14; 0.38]vs. 0.34 [0.24; 0.45]; p = 0.006). 44.4% of pts. in the VF/SCA group had a lowest T/R ratio among leads II & V5 ≤ 0.17 compared to 11.4% in the non-VF/SCA group (p < 0.001). In multivariate analysis, a lowest T/R ratio among leads II & V5 ≤ 0.17 was independently associated with VF/SCA (OR 6.10, 95% CI 1.92-19.40; p = 0.002). Type 1 Brugada pattern in the peripheral leads (OR 10.78) and early repolarization (OR 3.60) were other independent markers of VF/SCA.

CONCLUSION

A low T/R ratio among leads II & V5 is an independent marker for VF/SCA risk in patients with type-1 Brugada pattern.

[Epidemiology and pathophysiology of atrial fibrillation]

Epidemiology and pathophysiology of atrial fibrillation. Atrial fibrillation (AF) is the most common clinically significant cardiac arrhythmia worldwide. Its incidence and prevalence (currently 1 to 4% of the world population) are increasing. Most of the cardiovascular risk factors increase the risk of developing AF. AF is associated with a doubling risk of total mortality; it increases also the risk of stroke by 4-5 fold and therefore represents a public health problem. Mechanistically, the anarchic electrical activity recorded in the atrium in AF can be triggered by arrhythmogenic foci located in the pulmonary veins. In persistent AF, deep alterations in cellular electrophysiology, calcium metabolism, and extracellular matrix are observed, which tend to perpetuate the arrhythmia.

Sex influences on ventricular repolarization duration in normal subjects and in type 1, 2 and 3 long QT syndrome patients: Different effect in acquired and congenital type 2 LQTS

AIM

To evaluate the interaction between sex and rate corrected QT interval (QTc) duration in normal subjects after drug-induced QT prolongation and in LQTS patients.

METHODS

Semi-automated measurements were performed on 875 digital ECGs (200 normal subjects off drugs (100 females), 200 normal subjects on Moxifloxacin (100 females), 259 LQT1 patients (161 females), 183 LQT2 patients (100 females) and 33 LQT3 patients (15 females)). A sex specific coefficient was calculated in each group and was used to calculate group specific corrected QT intervals (QTci).

RESULTS

The mean sex difference (female minus male) in QTci interval duration was 17 ms 95%CI(12.7; 21.3) in normal subjects, 19 ms (14.5; 23.5) on Moxifloxacin, and 13 ms (4.8; 21.2) in LQT1 patients. The mean difference was 2 ms (-7.9; 11.9) in LQT2 and - 5 ms (-32.2; 22.2) in LQT3 patients (p = 0.0067 for the group and sex interaction). In the subgroup of patients above 15 years and without beta blocker treatment, the sex effect (female minus male) on QTci interval duration was 17 ms (4.1; 29.9) in LQT1 patients. QTc duration was not different between sex in LQT2 and in LQT3 patients (mean difference - 3 ms (-21.6; 15.6) and 12 ms (-28.4; 52.4), respectively) (p = 0.0191 for group and sex interaction).

CONCLUSIONS

The interaction between sex and QTc interval is preserved in type 1 LQTS and drug-induced QTc prolongation but blurred in type 2 LQTS. Further experimental studies are warranted to better understand the interaction of sexual hormones with malfunctioning KCNH2 encoded repolarizing potassium channel.

High Risk of Sustained Ventricular Arrhythmia Recurrence After Acute Myocarditis

Acute myocarditis is associated with cardiac arrhythmia in 25% of cases; a third of these arrhythmias are ventricular tachycardia (VT) or ventricular fibrillation (VF). The implantation of a cardiac defibrillator (ICD) following sustained ventricular arrhythmia remains controversial in these patients. We sought to assess the risk of major arrhythmic ventricular events (MAEs) over time in patients implanted with an ICD following sustained VT/VF in the acute phase of myocarditis compared to those implanted for VT/VF occurring on myocarditis sequelae. Our retrospective observational study included patients implanted with an ICD following VT/VF during acute myocarditis or VT/VF on myocarditis sequelae, from 2007 to 2017, in 15 French university hospitals. Over a median follow-up period of 3 years, MAE occurred in 11 (39%) patients of the acute myocarditis group and 24 (60%) patients of the myocarditis sequelae group. Kaplan–Meier MAE rate estimates at one and three years of follow-up were 19% and 45% in the acute group, and 43% and 64% in the sequelae group. Patients who experienced sustained ventricular arrhythmias during acute myocarditis had a very high risk of VT/VF recurrence during follow-up. These results show that the risk of MAE recurrence remains high after resolution of the acute episode.

Low rates of immediate coronary angiography among young adults resuscitated from sudden cardiac arrest

AIM

Coronary artery disease (CAD) has recently been emphasized as a major cause of sudden cardiac arrest (SCA) in young adults. We aim to assess the rate of immediate coronary angiography performance in young patients resuscitated from SCA.

METHODS

From May 2011 to May 2017, all cases of out-of-hospital SCA aged 18-40 years alive at hospital admission were prospectively included in 48 hospitals of the Great Paris area. Cardiovascular causes of SCA were centrally adjudicated, and management including immediate coronary angiography performance was assessed.

RESULTS

Out of 3579 SCA admitted alive, 409 (11.4%) patients were under 40 years of age (32.3 ± 6.2 years, 69.7% males), with 244 patients having a definite cause identified. Among those, CAD accounted for 72 (29.5%) cases, of which 64 (88.9%) were acute coronary syndromes. The rate of immediate coronary angiography was only 41.7% compared to 65.1% among those ≥40-years (P < 0.001). During the study period, while the rate of immediate coronary angiography increased from 60.5% to 70.3% (P < 0.001) in patients aged ≥40 years, the rate in patients aged less than 40 years remained stable (43.5% to 45.3%, P = 0.795). Patients younger than 40 years were significantly less likely to undergo immediate coronary angiography (OR = 0.34, 95% CI: 0.25-0.47), although early angiography was associated with survival at hospital discharge (OR = 2.68, 95% CI: 1.21-6.00).

CONCLUSION

CAD is the first cause of SCA in young adults aged less than 40 years. The observed low rates of immediate coronary angiography suggest a missed opportunity for early intervention.

Extracorporeal cardiopulmonary resuscitation in out-of-hospital cardiac arrest: a registry study

Aims

Out-of-hospital cardiac arrest (OHCA) without return of spontaneous circulation (ROSC) despite conventional resuscitation is common and has poor outcomes. Adding extracorporeal membrane oxygenation (ECMO) to cardiopulmonary resuscitation (extracorporeal-CPR) is increasingly used in an attempt to improve outcomes.

Methods and results

We analysed a prospective registry of 13 191 OHCAs in the Paris region from May 2011 to January 2018. We compared survival at hospital discharge with and without extracorporeal-CPR and identified factors associated with survival in patients given extracorporeal-CPR. Survival was 8% in 525 patients given extracorporeal-CPR and 9% in 12 666 patients given conventional-CPR (P = 0.91). By adjusted multivariate analysis, extracorporeal-CPR was not associated with hospital survival [odds ratio (OR), 1.3; 95% confidence interval (95% CI), 0.8–2.1; P = 0.24]. By conditional logistic regression with matching on a propensity score (including age, sex, occurrence at home, bystander CPR, initial rhythm, collapse-to-CPR time, duration of resuscitation, and ROSC), similar results were found (OR, 0.8; 95% CI, 0.5–1.3; P = 0.41). In the extracorporeal-CPR group, factors associated with hospital survival were initial shockable rhythm (OR, 3.9; 95% CI, 1.5–10.3; P = 0.005), transient ROSC before ECMO (OR, 2.3; 95% CI, 1.1–4.7; P = 0.03), and prehospital ECMO implantation (OR, 2.9; 95% CI, 1.5–5.9; P = 0.002).

Conclusions

In a population-based registry, 4% of OHCAs were treated with extracorporeal-CPR, which was not associated with increased hospital survival. Early ECMO implantation may improve outcomes. The initial rhythm and ROSC may help select patients for extracorporeal-CPR.

2404The use of wearable cardioverter defibrillator in France

Background

The wearable cardioverter defibrillator (WCD) has been shown to be useful during transient periods of high sudden cardiac death risk, and the issue of compliance recently pointed out. This Registry was designed to provide real-world data on WCD use in France, in terms of compliance, potential adverse events, as well as efficacy.

Methods and results

Multicenter evaluation (WEARIT FRANCE Registry) was conducted in France between January 2017 and March 2018. Overall, 1,157 patients were analyzed: 950 with ischemic heart disease (82%, including 647 patients after myocardial infarction), 119 after ICD explant (10%), and 88 pre-transplant (8%). The median age was 61 years; the median ejection fraction was 25%. Median WCD wear time was 62 days, with median daily use of 23.4 hours. Less than 1% of patients did not wear WCD at least 4 hours per day. During follow-up, a total of 42 sustained ventricular tachyarrhythmias (VT/VF) occurred in 36 patients, of whom 50% (n=18) received appropriate WCD shocks, giving an incidence of appropriate therapy of 1.56%. The rate of all VT/VF episodes were 3.1% among patients with ischemic cardiomyopathy (n=29/950) versus 3.4% for the others (n=7/207). Of the ischemic patients wearing beyond 30 days (N=784), 5 received appropriate therapy of VT/VF episodes. Overall shock survival was 100%. At the end of the WCD period, 586 patients (51%) were implanted with an implantable cardioverter defibrillator. Eight patients (0.69%) received inappropriate WCD shocks. Regarding the apparent very low proportion of women considered for WCD therapy, we aimed to appreciate in which extent

Conclusions

In this multicenter nationwide WCD evaluation, 3.1% of patients presented with sustained VT/VF with 47% of those patients developing VT/VF after 30 days. The incidence of inappropriate therapy was low. The compliance to WCD in this real life evaluation was very high. These data suggest that the WCD, when worn appropriately, may be helpful in the arsenal to protect high-risk patients against SCD, especially in case of transient risk situations.

Acknowledgement/Funding

Zoll

Prophylactic implantable cardioverter-defibrillator in the very elderly

Aims

Current guidelines do not propose any age cut-off for the primary prevention implantable cardioverter-defibrillator (ICD). However, the risk/benefit balance in the very elderly population has not been well studied.

Methods and results

In a multicentre French study assessing patients implanted with an ICD for primary prevention, outcomes among patients aged ≥80 years were compared with <80 years old controls matched for sex and underlying heart disease (ischaemic and dilated cardiomyopathy). A total of 300 ICD recipients were enrolled in this specific analysis, including 150 patients ≥80 years (mean age 81.9 ± 2.0 years; 86.7% males) and 150 controls (mean age 61.8 ± 10.8 years). Among older patients, 92 (75.6%) had no more than one associated comorbidity. Most subjects in the elderly group got an ICD as part of a cardiac resynchronization therapy procedure (74% vs. 46%, P < 0.0001). After a mean follow-up of 3.0 ± 2 years, 53 patients (35%) in the elderly group died, including 38.2% from non cardiovascular causes of death. Similar proportion of patients received ≥1 appropriate therapy (19.4% vs. 21.6%; P = 0.65) in the elderly group and controls, respectively. There was a trend towards more early perioperative events (P = 0.10) in the elderly, with no significant increase in late complications (P = 0.73).

Conclusion

Primary prevention ICD recipients ≥80 years in the real world had relatively low associated comorbidity. Rates of appropriate therapies and device-related complications were similar, compared with younger subjects. Nevertheless, the inherent limitations in interpreting observational data on this particular competing risk situation call for randomized controlled trials to provide definitive answers. Meanwhile, a careful multidisciplinary evaluation is needed to guide patient selection for ICD implantation in the elderly population.

High risk of heart failure associated with desmoglein-2 mutations compared to plakophilin-2 mutations in arrhythmogenic right ventricular cardiomyopathy/dysplasia

BACKGROUND

Previous studies suggested that genetic status affects the clinical course of arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) patients. The aim of this study was to compare the outcome of desmoglein-2 (DSG2) mutation carriers to those who carry the plakophilin-2 (PKP2) mutation, the most common ARVC/D-associated gene.

METHODS AND RESULTS

Consecutive ARVC/D patients carrying a pathogenic mutation in PKP2 or DSG2 were selected from a national ARVC/D registry. The cumulative freedom from sustained ventricular arrhythmia and cardiac transplantation/death from heart failure (HF) during follow-up was assessed, compared between PKP2 and DSG2, and predictors for ventricular arrhythmia and HF events determined. Overall, 118 patients from 78 families were included: 27 (23%) carried a DSG2 mutation and 91 (77%) a PKP2 mutation. There were no significant differences between DSG2 and PKP2 mutation carriers concerning gender, proband status, age at diagnosis, T-wave inversion, or right ventricular dysfunction at baseline. DSG2 patients displayed more frequent epsilon wave (37% vs. 17%, P = 0.048) and left ventricular dysfunction at diagnosis (54% vs. 10%, P < 0.001). During a median follow-up of 5.6 years (2.5-16), DSG2 and PKP2 mutation carriers displayed a similar risk of sustained ventricular arrhythmia (log-rank P = 0.20), but DSG2 mutation carriers were at higher risk of transplantation/HF-related death (log-rank P < 0.001). The presence of a DSG2 mutation vs. PKP2 mutation was a predictor of transplantation/HF-related death in univariate Cox analysis (P = 0.0005).

CONCLUSIONS

In this multicentre cohort, DSG2 mutation carriers were found to be at high risk of end-stage HF compared to PKP2 mutation carriers, supporting careful haemodynamic monitoring of these patients. The benefit of early HF treatment needs to be assessed in DSG2 carriers.

Treatment of cardiac sarcoidosis: A comparative study of steroids and steroids plus immunosuppressive drugs

BACKGROUND

We aimed to compare the efficacy of steroids alone or associated with immunosuppressive drugs for the prevention of relapse in cardiac sarcoidosis (CS).

METHODS

In this monocentric multidisciplinary retrospective single center study, all consecutive patients with histologically proven sarcoidosis hospitalized from January 2012 to December 2016 were considered. All patients with symptomatic CS were studied. Patients received steroids or steroids plus immunosuppressive drugs (IS) for CS treatment at diagnosis. The efficacy of each treatment strategy (steroids vs steroids + IS) was assessed by the cardiac relapse rate over follow up.

RESULTS

326 consecutive patients with histologically proven sarcoidosis were screened. Among them, 36 (11%) had symptomatic CS (20 (55.5%) men, median age at diagnosis 48.5 [22.8-76]). Twenty-four patients received steroids and 12 received steroids + IS (azathioprine n = 5, methotrexate n = 5, cyclophosphamide n = 2) at CS diagnosis. Over a median follow up of 3.6 [1-15.2] years, 13 (36.1%) patients suffered a cardiac relapse including reduced left ventricular ejection fraction (LVEF, n = 4), third degree heart block (n = 2), atrio-ventricular (n = 1) or ventricular (n = 1) tachycardia and sudden cardiac death (n = 1). Except for a higher frequency of black patients in patients receiving IS, CS features at diagnosis and median time to relapse did not significantly differ between patients who did or did not receive IS. Relapse rate was 45.8% in the steroids group versus 16.7% in the steroids + IS group (p = 0.048).

CONCLUSIONS

In cardiac sarcoidosis, the combination of steroids with immunosuppressive drugs might reduce the risk of cardiac relapse, as compared to steroids alone.