JACC. Clinical electrophysiology最新文献

Background: The automatic implantable cardioverter-defibrillator (ICD) is effective in preventing arrhythmic sudden cardiac death in patients with hypertrophic cardiomyopathy (HCM). The extravascular (EV) ICD provides antitachycardia pacing and defibrillation capabilities while avoiding transvenous lead complications.

Objectives: This study sought to evaluate the safety and performance of the novel EV-ICD in patients with HCM.

Methods: This analysis was derived from the Pivotal EV-ICD Study, an international, multicenter, interventional trial evaluating the EV-ICD in patients with guideline-based indications for ICD therapy. Patients were classified according to the presence of a diagnosis of HCM at baseline. The main efficacy endpoint was successful defibrillation testing at implantation. The main safety endpoint was freedom from system- or procedure-related major complications through 3 years of follow-up.

Results: A total of 316 patients (mean age 53.8 ± 13.1 years, 25% female, 41 [13%] with HCM) underwent attempted EV-ICD placement. The implantation success rate was 92.7% in HCM patients and 94.9% in non-HCM patients (P = 0.47). Defibrillation testing was successful in 100% and 98.5% of HCM and non-HCM patients, respectively (P = 1.00). During a mean follow-up of 30.6 ± 8.5 months, 1 (2.6%) HCM patient received appropriate ICD therapy (shock for ventricular fibrillation), compared with 23 (8.8%) non-HCM patients (log-rank P = 0.20). Inappropriate ICD therapies occurred in 7 (18.4%) HCM and 41 (15.7%) non-HCM patients (log-rank P = 0.80). System- and procedure-related major complications occurred in 12.2% of HCM and 8.7% of non-HCM patients (log-rank P = 0.44).

Conclusions: In patients with HCM, the EV-ICD demonstrated high defibrillation success and a safety profile similar to what was observed in non-HCM patients.

Background: Antitachycardia pacing (ATP) therapy applies a sequence of pacing pulses to terminate ventricular tachycardia (VT). Clinically, left bundle branch area (LBBA) pacing has emerged as a novel way to induce synchronous ventricular activation.

Objectives: The main aim of this study was to compare the efficacy and safety of ATP delivered to an LBBA lead and a conventional right ventricular (RV) lead.

Methods: Using a preclinical animal model (n = 7), pacing leads were implanted in the RV apex and LBBA and connected to implantable cardioverter-defibrillators. The left anterior descending artery was occluded for 2 hours to cause an ischemia-reperfusion injury. Four days following ischemia-reperfusion injury, VT episodes were induced using programmed pacing, and burst ATP therapy was delivered to the RV/LBBA leads for each VT episode. Activation sequences from an implanted basket catheter were determined for the pretherapy VT and ATP beats.

Results: VT was induced 80 times, with a mean VT cycle length of 180.0 ± 30.0 milliseconds. ATP delivered to the LBBA terminated VT more often than RV ATP (70.2% vs 47.3%; P = 0.040). There was no significant difference in VT acceleration or ventricular fibrillation induction. The number of ATP pulses required for the activation sequences to correlate with the captured ATP pattern rather than the pretherapy VT pattern was lower for LBBA compared to RV ATP (4.1 vs 5.1 pulses; P = 0.047).

Conclusions: Improved performance of LBBA compared to RV ATP provides an incentive for future clinical studies in patients who are at risk of sudden cardiac death.

Background: There are limited data on genotype as a risk marker of sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM). It remains unknown whether family history of SCD (FHxSCD) is a risk marker of SCD independently of genotype.

Objectives: The goal of this study was to assess the association of genotype and FHxSCD with SCD outcomes in HCM and investigate methods for incorporation of genotype into SCD risk stratification models.

Methods: This historical cohort study used registries of 2 HCM referral centers. Association of FHxSCD and genotype with SCD was assessed by multivariable hazard regression analysis.

Results: Of 3,258 patients, 896 (27.5%) were genotype-positive, and 332 (10.2%) had FHxSCD. During 4.9 years' median follow-up, 114 patients reached the SCD outcome. On multivariable analysis, the hazard ratios for SCD were 1.83 (95% CI: 1.161-2.9; P = 0.01) for FHxSCD and 1.52 (95% CI: 1.01-2.31; P = 0.047) for being genotype-positive. Among patients with FHxSCD but no other risk markers, the risk of SCD events was 6.4% at 5 years (95% CI: 2.7%-14.9%) in genotype-positive patients and 2.6% (95% CI: 0.6%-10.0%) in genotype-negative patients.

Conclusions: FHxSCD remained independently associated with SCD in adult patients with HCM even after adjusting for genotype. Among patients with FHxSCD but no other risk markers, genotype-positive patients were at high risk of SCD but genotype-negative patients were not. These data suggest that ICD insertion is not indicated for most genotype-negative patients with FHxSCD unless other risk markers are present.

Background: Left bundle branch pacing (LBBP) enables physiological activation by capturing the left conduction system at various sites. However, whether mechanical synchrony and efficiency vary depending on the pacing location remains unclear.

Objective: The study aim was to evaluate whether left ventricular (LV) mechanical performance varies among different LBBP sites and whether paced mechanical synchrony replicates intrinsic LV activation across locations.

Methods: This prospective cohort study included 114 patients with preserved LV ejection fraction who received LBBP for bradycardia indications. At follow-up, echocardiographic analysis included strain-derived and myocardial work parameters. In patients with intrinsic rhythm, within-patient comparisons between intrinsic and paced beats were performed.

Results: Central LBB capture (left bundle trunk or septal fascicle pacing) was achieved in 60 patients of 106 patients (56.6%) and peripheral LBB capture (left posterior or left anterior fascicle pacing) in 46 of 106 patients (43.4%). No significant differences in global longitudinal strain or myocardial work indices (global work index, global constructive work, global wasted work, or global work efficiency) were found between central and peripheral LBB captures. Compared with intrinsic rhythm, LBBP did not lead to significant differences in global work efficiency, global work index, global constructive work, or global wasted work, and the echocardiographic changes from intrinsic to paced rhythm were similar between study groups.

Conclusions: In patients with preserved LV ejection fraction, mechanical synchrony and work efficiency were similar across LBB pacing sites. These findings support a pragmatic approach centered on achieving conduction system capture rather than targeting specific anatomical locations.