Batra, Anjan S.

Implantable cardioverter-defibrillator (ICD) therapy in children and congenital heart disease (CHD) patients is hampered by poor long-term lead survival. Lead extraction is technically difficult and carries substantial morbidity. Manufacturers developed distinct strategies for this issue: thinner lead bodies or a Gore ePTFE coil coating. Both design changes were thought to improve ease of lead removal, but have not been directly compared in children or adults. The purpose of this study was to assess thin and ePTFE-coated ICD lead survival in pediatric and CHD pts. Methods: The Pediatric Lead Extractability and Survival Evaluation (PLEASE) Study began as a Phase IV multicenter open-label prospective study [ NCT00335036 ], facilitated by the Pediatric & Congenital EP Society. Initially designed as a randomized study, it changed to a parallel assignment registry when 1 lead had an advisory due to high incidence of failure, prompting concern about continued clinical equipoise. Pediatric and CHD pts who underwent ICD lead implant from 2005-2010 were eligible. The end date was NCDR ICD Registry v2.0 release (includes pediatric & lead data). 23 centers participated; each site obtained IRB approval. De-identified data was sent to the PI center for verification and statistical analyses. Results: A total of 982 ICD pts (357 VVI, 558 DDD, 67 CRT-D) entered the PLEASE study, incl. 423 pts (43%) with CHD. Mean age at implant = 18.3 ± 9.9 yrs. Thin (< 7Fr) ICD leads accounted for 51%, 23% were ePTFE-coated, 26% neither thin nor coated. There were 113 ICD lead failures (11.5%) at a mean lead-age of 2.2 ± 1.7 yrs, causing shocks in 55 pts. Failure occurred in 21% of thin leads vs 3.5% of ePTFE leads (p<0.01). Extraction was performed on 142 (14.5%) leads overall; 21% of thin leads (incl. extraction of 29 functioning leads due to recall) vs. 4.4% of ePTFE leads (p<0.01). There were 7 major extraction complications (4.9%), but no procedural mortality. Among thin leads, 90/270 (33.3%) of recalled leads failed vs 15/229 (6.6%) non-recalled thin leads. Conclusions: This Phase IV study demonstrates that ICD leads in children and CHD pts have suboptimal performance overall. Thinner leads were much more likely to fail and/or be extracted compared with ePTFE leads, chiefly driven by one lead type.

BACKGROUND: In severely affected patients with catecholaminergic polymorphic ventricular tachycardia, beta-blockers are often insufficiently protective. The purpose of this study was to evaluate whether flecainide is associated with a lower incidence of arrhythmic events (AEs) when added to beta-blockers in a large cohort of patients with catecholaminergic polymorphic ventricular tachycardia. METHODS: From 2 international registries, this multicenter case cross-over study included patients with a clinical or genetic diagnosis of catecholaminergic polymorphic ventricular tachycardia in whom flecainide was added to beta-blocker therapy. The study period was defined as the period in which background therapy (ie, beta-blocker type [beta1-selective or nonselective]), left cardiac sympathetic denervation, and implantable cardioverter defibrillator treatment status, remained unchanged within individual patients and was divided into pre-flecainide and on-flecainide periods. The primary end point was AEs, defined as sudden cardiac death, sudden cardiac arrest, appropriate implantable cardioverter defibrillator shock, and arrhythmic syncope. The association of flecainide with AE rates was assessed using a generalized linear mixed model assuming negative binomial distribution and random effects for patients. RESULTS: A total of 247 patients (123 [50%] females; median age at start of flecainide, 18 years [interquartile range, 14–29]; median flecainide dose, 2.2 mg/kg per day [interquartile range, 1.7–3.1]) were included. At baseline, all patients used a beta-blocker, 70 (28%) had an implantable cardioverter defibrillator, and 21 (9%) had a left cardiac sympathetic denervation. During a median pre-flecainide follow-up of 2.1 years (interquartile range, 0.4–7.2), 41 patients (17%) experienced 58 AEs (annual event rate, 5.6%). During a median on-flecainide follow-up of 2.9 years (interquartile range, 1.0–6.0), 23 patients (9%) experienced 38 AEs (annual event rate, 4.0%). There were significantly fewer AEs after initiation of flecainide (incidence rate ratio, 0.55 [95% CI, 0.38–0.83]; P =0.007). Among patients who were symptomatic before diagnosis or during the pre-flecainide period (n=167), flecainide was associated with significantly fewer AEs (incidence rate ratio, 0.49 [95% CI, 0.31–0.77]; P =0.002). Among patients with ≥1 AE on beta-blocker therapy (n=41), adding flecainide was also associated with significantly fewer AEs (incidence rate ratio, 0.25 [95% CI, 0.14–0.45]; P <0.001). CONCLUSIONS: For patients with catecholaminergic polymorphic ventricular tachycardia, adding flecainide to beta-blocker therapy was associated with a lower incidence of AEs in the overall cohort, in symptomatic patients, and particularly in patients with breakthrough AEs while on beta-blocker therapy.

Importance Whether vigorous intensity exercise is associated with an increase in risk of ventricular arrhythmias in individuals with hypertrophic cardiomyopathy (HCM) is unknown. Objective To determine whether engagement in vigorous exercise is associated with increased risk for ventricular arrhythmias and/or mortality in individuals with HCM. The a priori hypothesis was that participants engaging in vigorous activity were not more likely to have an arrhythmic event or die than those who reported nonvigorous activity. Design, Setting, and Participants This was an investigator-initiated, prospective cohort study. Participants were enrolled from May 18, 2015, to April 25, 2019, with completion in February 28, 2022. Participants were categorized according to self-reported levels of physical activity: sedentary, moderate, or vigorous-intensity exercise. This was a multicenter, observational registry with recruitment at 42 high-volume HCM centers in the US and internationally; patients could also self-enroll through the central site. Individuals aged 8 to 60 years diagnosed with HCM or genotype positive without left ventricular hypertrophy (phenotype negative) without conditions precluding exercise were enrolled. Exposures Amount and intensity of physical activity. Main Outcomes and Measures The primary prespecified composite end point included death, resuscitated sudden cardiac arrest, arrhythmic syncope, and appropriate shock from an implantable cardioverter defibrillator. All outcome events were adjudicated by an events committee blinded to the patient’s exercise category. Results Among the 1660 total participants (mean [SD] age, 39 [15] years; 996 male [60%]), 252 (15%) were classified as sedentary, and 709 (43%) participated in moderate exercise. Among the 699 individuals (42%) who participated in vigorous-intensity exercise, 259 (37%) participated competitively. A total of 77 individuals (4.6%) reached the composite end point. These individuals included 44 (4.6%) of those classified as nonvigorous and 33 (4.7%) of those classified as vigorous, with corresponding rates of 15.3 and 15.9 per 1000 person-years, respectively. In multivariate Cox regression analysis of the primary composite end point, individuals engaging in vigorous exercise did not experience a higher rate of events compared with the nonvigorous group with an adjusted hazard ratio of 1.01. The upper 95% 1-sided confidence level was 1.48, which was below the prespecified boundary of 1.5 for noninferiority. Conclusions and Relevance Results of this cohort study suggest that among individuals with HCM or those who are genotype positive/phenotype negative and are treated in experienced centers, those exercising vigorously did not experience a higher rate of death or life-threatening arrhythmias than those exercising moderately or those who were sedentary. These data may inform discussion between the patient and their expert clinician around exercise participation.