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Patients with catecholaminergic polymorphic ventricular tachycardia (CPVT) are at risk for malignant ventricular arrhythmias during exercise and emotions which may lead to sudden cardiac death. Beta-blockers (BB) are the mainstay of therapy in patients with CPVT, but studies comparing the efficacy of different types of BB are scarce. Our objective was to determine the efficacy of different types of BB in reducing the ventricular arrhythmia (VA) severity on exercise stress test (EST) in patients with CPVT. Data was derived from the International CPVT Registry, a large retrospective cohort study. We included patients who had an EST before (pre-EST) and after start of BB (post-EST). We divided the cohort into five groups based on the first prescribed BB and compared pre-EST and post-EST. We included 428 patients (median age 18.5 [11.7–39.6] years, 240 (56.%) female), 155 (36.2%) probands) of whom 38 (8.9%) used atenolol, 131 (30.6%) bisoprolol, 82 (19.2%) metoprolol, 124 (29.0%) nadolol and 53 (12.4%) propranolol. Sex and history of aborted cardiac arrest were similar in all groups. The age at start of BB differed (p Based on these results we conclude that all beta-blockers except atenolol are effective in reducing the VA severity on EST in patients with CPVT. Funding Acknowledgement Type of funding source: Public grant(s) – EU funding. Main funding source(s): E-Rare Joint Transnational Call for Proposals 2015 “Improving Diagnosis and Treatment of Catecholaminergic Polymorphic Ventricular Tachycardia: Integrating Clinical and Basic Science”

Background Brugada syndrome (BrS) is an inherited arrhythmia syndrome with an increased risk of SCD. While Subcutaneous ICD (S-ICD) is a seductive approach to treat these patients, questions raised on the risk of inappropriate shock in this specific population. Objective The aim of this study was to evaluate the safety and the effectiveness of the S-ICD in BrS patients. Methods We prospectively enrolled 112 BrS patients implanted with S-ICD in 17 European centers. During the screening at least 2 vectors must be suitable but it was not necessary to check for the suitability of the ECG during sodium channel blocker or exercise test. S-ICD indications follow the current guidelines. Results Mean age of patients was 45±13 years, with 95 (85%) males. Implantation was performed in 91 (83%) patients for primary prevention and in 18 (16%) patients for secondary prevention. There is an indication of ICD replacement for 16 patients (14%): 13 lead defect (81%), 1 infection (6%) and 2 ICD end of life (13%). In this cohort, 57 patients (51%) had spontaneous type I BrS, 60 patients (55%) were symptomatic: 10 resuscitated SCD (17%) and 48 (83%) syncope. Implantation was performed under general anesthesia in 79 patients (71%). The mean operation time was 56±19 min. The lead was placed at the left side of the sternum in 102 patients (92%) and at the right side in 9 (8%). Sensing configuration was the primary vector for 46 patients (41%), secondary vector for 57 (51%) and alternative vector for 9 (8%). No complications occurred during implantation. During a mean follow-up of 15.6 months (0–39 months), 6 patients (5%) had at least one appropriate shock (n=9). The rate of appropriate shock was 4.5%/y. All the VF episodes were successfully treated with the first shock. One patient had VF ablation for recurrent VF. Among the 6 patients who received an appropriate shock, 3 (50%) were implanted for secondary prevention and 3 (50%) were implanted for primary prevention including 2 patients with a history of syncope and one asymptomatic patient. Twelve patients (11%) had at least one inappropriate shock (n=22) including 2 patients with respectively 8 and 4 inappropriate shocks due to T-wave oversensing. With the SMART pass system the first patient had no more inappropriate shock for now 2 years. The rate of inappropriate shock was 9%/y. One patient died of myocardial infarction. Five patients (4%) were hospitalized for complications (4 pocket or scar infections and 1 electrode failure). Conclusion Our initial experience showed that S-ICD is efficient to treat VF episode in BrS patients. In this population, the rate of inappropriate shock was 9%/y. In view of these results, S-ICD implantation seems to be efficient to protect BrS patients against SCD. Acknowledgement/Funding Investigator-Sponsored Research program, Boston Scientific

Recent studies have shown that in more than half of apparently unexplained sudden cardiac arrests (SCA), a specific aetiology can be unmasked by a careful evaluation. The characteristics and the extent to which such cases undergo a systematic thorough investigation in real-life practice are unknown.Data were analysed from an ongoing study, collecting all cases of out-of-hospital cardiac arrest in Paris area. Investigations performed during the index hospitalization or planned after discharge were gathered to evaluate the completeness of assessment of unexplained SCA. Between 2011 and 2016, among the 18 622 out-of-hospital cardiac arrests, 717 survivors (at hospital discharge) fulfilled the definition of cardiac SCA. Of those, 88 (12.3%) remained unexplained after electrocardiogram, echocardiography, and coronary angiography. Cardiac magnetic resonance imaging yielded the diagnosis in 25 (3.5%) cases, other investigations accounted for 14 (2.4%) additional diagnoses, and 49 (6.8%) patients were labelled as idiopathic ventricular fibrillation (IVF) (48.7 ± 15 years, 69.4% male). Among those labelled IVF, only 8 (16.3%) cases benefited from a complete workup (including pharmacological testing). Younger patients [odds ratio (OR) 6.00, 95% confidence interval (CI) 1.80-22.26] and those admitted to university centres (OR 3.60, 95% CI 1.12-12.45) were more thoroughly investigated. Genetic testing and family screening were initiated in only 9 (18.4%) and 12 (24.5%) cases, respectively.Our findings suggest that complete investigations are carried out in a very low proportion of unexplained SCA. Standardized, systematic approaches need to be implemented to ensure that opportunities for specific therapies and preventive strategies (including relatives) are not missed.

Aims Congestive heart failure (CHF) is associated with severe structural changes of atria, contributing to impaired atrial function and the risk of arrhythmia. This study investigated the effects of CHF treatments on atrial remodelling. Methods and results Three months after myocardial infarction (MI), rats were treated for 1 month with spironolactone, lisinopril, or atenolol alone or in combination. Echocardiography–Doppler tissue imaging, haemodynamic measurements, and 24-h Holter monitoring were used to characterize the cardiomyopathy. Atrial fibrosis was quantified with Picrosirius Red staining. Left atrial diameter was increased (5.8±0.6 mm in MI vs. 3.6±0.3 mm in sham; P

The efficacy of beta-blockers was tested in 11 patients who avoided sudden death as a result of ventricular tachycardia or fibrillation due to coronary artery disease or non-ischaemic underlying heart disease, after implantation of an automatic defibrillator. Ten patients initially tolerated acebutolol despite prior class III or IV heart failure in six cases; nadolol replaced acebutolol in nine cases for long-term therapy. In these 10 patients, periods of treatment with and without beta-blocking agent were available, making possible a crossover comparison, during a follow-up lasting 31.6 +/- 17.8 months. One hundred and ten shocks were delivered: 14 were considered as probably inappropriate and ruled out, leaving the remaining 96 shocks to be analysed. The monthly rate of shocks was lower during beta-blocking treatment: 0.12 +/- 0.24 vs. 1.09 +/- 1.41 (P = 0.03). While taking beta-blockers, only four patients received shocks, compared to 10 (i.e. all cases) not administered beta-blockers (P less than 0.01). Despite the technical limitations of the study, since only a few spontaneous shocks could be documented on ECG recordings, the efficacy of beta-blockers in preventing occurrence of severe ventricular tachyarrhythmias seems likely, and deserves further investigations using new implanted devices with improved memory functions.

An analysis of heart rate (HR) variability (HRV) was based on quantifying the number and amplitude of HR fluctuations over long (8–30 cycles) and short (2–4 cycles) sequences of acceleration and deceleration-forming oscillations. The ‘product’ (number times amplitude) is an equivalent of the power spectrum in the frequency domain. In the time domain, positive correlations with HR were found for the number of long (L) sympathetic-mediated oscillations, whereas they were negative for short (S) vagally-mediated oscillations. The L/S ratio, an index of the autonomic nervous system (ANS) balance, closely paralleled the circadian HR values. HRV was studied in the ambulatory ECG of three groups of 15 normal adults (group I), 13 patients with left ventricular hypertrophy (LVH, group II) and 13 patients-with heart failure (HF, group III). In basic conditions the mean HR was 77.1 ±l.9 beats min−1 (mean±SEM) in group 1, 76.8±3.3 in II, 79.5±3.5 in III (P = NS). The different types of oscillations had smaller 24-h average values of the product in groups II and III than in group I, but the trends did not reach significance. However, the pooled 24 hourly values of the L/S ratio in group I (1.17 ± 0.09) were lower than in group II (1.33 ±0.06, P

An analysis of heart rate (HR) variability (HRV) was based on quantifying the number and amplitude of HR fluctuations over long (8-30 cycles) and short (2-4 cycles) sequences of acceleration and deceleration-forming oscillations. The 'product' (number times amplitude) is an equivalent of the power spectrum in the frequency domain. In the time domain, positive correlations with HR were found for the number of long (L) sympathetic-mediated oscillations, whereas they were negative for short (S) vagally-mediated oscillations. The L/S ratio, an index of the autonomic nervous system (ANS) balance, closely paralleled the circadian HR values. HRV was studied in the ambulatory ECG of three groups of 15 normal adults (group I), 13 patients with left ventricular hypertrophy (LVH, group II) and 13 patients with heart failure (HF, group III). In basic conditions the mean HR was 77.1 +/- 1.9 beats min-1 (mean +/- SEM) in group I, 76.8 +/- 3.3 in II, 79.5 +/- 3.5 in III (P = NS). The different types of oscillations had smaller 24-h average values of the product in groups II and III than in group I, but the trends did not reach significance. However, the pooled 24 hourly values of the L/S ratio in group I (1.17 +/- 0.09) were lower than in group II (1.33 +/- 0.06, P less than 0.05 at Ancova) and higher than in group III (1.06 +/- 0.09, P less than 0.001). A 3-day treatment with acebutolol non-uniformly slowed the mean HR:--9.5% in group I, --18.1% in II and -19.1% in III (P less than 0.001), and uniformly diminished the L/S ratio by 17% to 20% (P less than 0.01). In conclusion, the sympathetic predominance of the ANS balance in LVH and HF is reflected by the beta-blockade induced HR decrease that is twice as marked in patients as in controls. In basic conditions HRV tends to be depressed in LVH and even more in HF. The ANS imbalance, however, has different modalities depending on the presence of HF, probably because of the different status of beta-adrenergic receptors in this condition.

Aims In patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), implantable cardioverter-defibrillator (ICD) shocks are sometimes ineffective and may even trigger fatal electrical storms. We assessed the efficacy and complications of ICDs placed in patients with CPVT who presented with a sentinel event of sudden cardiac arrest (SCA) while undiagnosed and therefore untreated. Methods and results We analysed 136 patients who presented with SCA and in whom CPVT was diagnosed subsequently, leading to the initiation of guideline-directed therapy, including β-blockers, flecainide, and/or left cardiac sympathetic denervation. An ICD was implanted in 79 patients (58.1%). The primary outcome of the study was sudden cardiac death (SCD). The secondary outcomes were composite outcomes of SCD, SCA, appropriate ICD shocks, and syncope. After a median follow-up of 4.8 years, SCD had occurred in three patients (3.8%) with an ICD and none of the patients without an ICD (P = 0.1). SCD, SCA, or appropriate ICD shocks occurred in 37 patients (46.8%) with an ICD and 9 patients (15.8%) without an ICD (P Conclusion In previously undiagnosed patients with CPVT who presented with SCA, an ICD was not associated with improved survival. Instead, the ICD was associated with both a high rate of appropriate ICD shocks and inappropriate ICD shocks along with other device-related complications. Strict adherence to guideline-directed therapy without an ICD may provide adequate protection in these patients without all the potential disadvantages of an ICD.

Intravenous adenosine proved effective in eight out of ten episodes of acute spontaneous supraventricular tachycardia. AV node blockade induced by adenosine occurred 20 s after injection, and disappeared very quickly. Side-effects were transient and never serious. Therefore, it is thought that adenosine can be proposed safely for the short-term treatment of supraventricular tachycardia. Because of the different mechanisms of action, the specific side-effects observed after ATP administration are unlikely to be encountered.