JACC. Clinical electrophysiology最新文献

The vein of Marshall (VOM) is a patent segment of the left cardinal vein that shrinks during embryologic development. The VOM runs along the lateral ridge of the left atrium, between the left pulmonary veins and the left atrial appendage, where it colocalizes with fat, intrinsic nerves, and a vestigial epicardial musculature named the Marshall bundle (MB). Ectopic beats can originate from the MB and trigger atrial fibrillation (AF) under sympathetic input. It has also been shown that high-frequency stimulation of the parasympathetic intrinsic nerves near the VOM induces AF. Because fat-insulating properties strongly protect the MB against electric energy, it frequently supports epicardial gaps during mitral line ablation. The VOM is a true atrial vein that can be safely used as a vascular route for retrograde chemical ablation of these structures implicated in the AF process and mitral isthmus gaps. Recent randomized studies show that VOM ethanol infusion improves sinus rhythm maintenance in patients with persistent AF, all the more if combined with mitral line block, which it greatly facilitates. Beyond pulmonary vein isolation, anatomical atrial transection conditioned by successful VOM ethanol infusion seems a promising strategy for persistent AF ablation.

Background: Cardiac implantable electronic device (CIED) infection represents a significant cause of morbidity and increased health care costs in patients undergoing high-risk procedures.

Objective: This study sought to describe the incidence of infection using two prevention strategies: chlorhexidine gluconate (CHG) pocket irrigation vs antibacterial envelope (ABE).

Methods: In this retrospective observational study, patients undergoing high-risk CIED interventions (generator change, device upgrade, lead/pocket revision, cardiac resynchronization device implantation) between 2018 and 2024, in whom either CHG irrigation or ABE was used, were included. Propensity score matching using baseline and procedural characteristics (age, sex, previous infection, intervention within 60 days, type of device, type of intervention, PADIT [Prevention of Arrythmia Device Infection Trial] score, antibiotic used) was performed.

Results: A total of 1,749 patients (median age 73 years [Q1-Q3: 63-81 years], female 42%; CHG: n = 1,118) were included. After a median follow-up of 459 days (Q1-Q3: 192-852 days), there were no statistically significant differences in the risk of CIED-related infection (0.8% vs 0.8%; HR: 0.89; 95% CI: 0.3-2.66; log-rank P = 0.83) between the CHG and ABE groups. After propensity score matching, a total of 714 patients, without statistically significant differences in baseline characteristics, were analyzed. There were no significant differences in the risk of CIED-related infection (1.1% vs 1.1%; HR: 0.97; 95% CI: 0.24-3.86, log-rank P = 0.96). No adverse events associated with CHG irrigation occurred.

Conclusions: In high-risk procedures, CHG irrigation resulted in a similar risk of CIED-related infection as treatment with an ABE, without any adverse events. The lower cost of CHG and widespread availability could result in more patients being treated, thus extending the benefits to patients with a lower risk of infection.

Background: Conduction system pacing (CSP), including His bundle pacing (HBP) and left bundle branch area pacing (LBBAP), offers a physiological alternative to conventional pacing. However, current evidence is limited by small sample sizes, short follow-up, and inconsistent LBBAP definitions.

Objective: This study evaluated the long-term outcomes, safety, and lead performance of CSP in a large multicenter cohort, and provided a precise LBBAP classification for investigating its impact on clinical outcomes.

Methods: This prospective registry-based study included patients receiving CSP at 5 Chinese centers from 2019 to 2021. LBBAP was classified as left bundle branch pacing (LBBP), left ventricular septal pacing (LVSP), or unclassified LBBAP based on the presence, absence, or uncertainty of left bundle branch capture. Pacing and clinical outcomes were analyzed.

Results: Of 3,336 enrolled patients, 3,167 successfully received CSP (557 HBP, 2,610 LBBAP), with a mean follow-up of 41.3 ± 14.0 months. LBBAP comprised LBBP (84.2%), unclassified (12.5%), and LVSP (3.3%). In patients with LBBB and heart failure with reduced ejection fraction, LBBP and HBP achieved the greatest LVEF improvements (+20.7% and +21.9%), while LVSP showed the least (+12.1%). LVSP was associated with higher mortality or heart failure hospitalization (33.3%) compared with LBBP (8.6%) and unclassified LBBAP (15.4%). Threshold increases ≥1 V/0.5 ms occurred in 5.03% HBP vs 1.80% LBBAP (P < 0.001). Procedural complications (excluding threshold rise) occurred in 1.3% of both groups.

Conclusions: CSP demonstrated long-term safety and stability. Subclassification of LBBAP enhances clinical precision, with LBBP capture yielding a higher positive clinical outcomes and LVSP with inferior outcomes, especially in cardiac resynchronization therapy patients.

Background: The ring-like pattern of late gadolinium enhancement (RL-LGE) on cardiac magnetic resonance (CMR) has been proposed as a distinctive imaging marker of arrhythmogenic cardiomyopathy (ACM) with left ventricular (LV) involvement. However, the clinical characteristics and prognostic significance remain to be further clarified.

Objectives: This study sought to assess the clinical profile, genetic background, and prognostic significance of RL-LGE in ACM with LV involvement.

Methods: In this observational cohort study, we included consecutive patients with a diagnosis of biventricular or left-dominant ACM (BIV-ACM or LD-ACM). RL-LGE was defined as subepicardial or midmyocardial LGE involving ≥3 contiguous LV segments on the same short-axis slice. The primary endpoint was a composite of sudden cardiac arrest, sustained ventricular tachycardia, or implantable cardioverter-defibrillator (ICD) interventions.

Results: Among 149 patients (mean age 36 ± 12 years, 66% male), RL-LGE was identified in 73 (49%), most frequently in association with DSP variants, with a higher prevalence in BIV-ACM (70%) than in LD-ACM (30%). Over a median follow-up of 31 months, 24 patients experienced the primary endpoint, 67% of whom had RL-LGE. In multivariable Cox regression, RL-LGE emerged as an independent predictor of the primary endpoint (HR: 2.47; 95% CI: 1.10-6.02; P = 0.042), along with nonsustained ventricular tachycardia (HR: 2.62; 95% CI: 1.17-6.41; P = 0.033), whereas genetic status did not provide additional prognostic information. Incorporating RL-LGE into the arrhythmogenic right ventricular cardiomyopathy risk model significantly improved its predictive performance (likelihood ratio test: P = 0.006).

Conclusions: RL-LGE independently predicts arrhythmic events in ACM, regardless of genotype status, and refines the prognostic performance of traditional risk models. Its detection may aid in early recognition of high-risk patients and inform primary-prevention ICD therapy.

Background: Reaching a plateau post-pacing interval (PPI) while increasing the number of pacing stimuli (N_pace) of overdrive pacing is an indicator of establishing entrainment pacing.

Objectives: This study aimed to investigate whether the N_pace for attaining a plateau post-pacing interval (NPP) can be used for identifying re-entrant atrial tachycardia (AT) circuit.

Methods: We studied 43 ATs in 38 patients. At each pacing site, overdrive pacing with an N_pace of 1, 3, 5, and ≥7 was performed. NPP was defined as the smallest N_pace that caused an incremental increase in the PPI to become smaller than tachycardia cycle length (TCL) minus pacing cycle length. NPP was classified as 3, 5, and >5. The relationship between NPP and PPI under the establishment of entrainment pacing (PPI_entrained) was investigated. When PPI_entrained was unavailable, the relationship between NPP and findings on the activation maps was evaluated.

Results: NPP was acquired at 193 pacing sites. Among 170 pacing sites where PPI_entrained was available, 104 of 110 NPP =3 pacing sites had PPI_entrained - TCL ≤30 milliseconds, whereas all 32 NPP >5 pacing sites had PPI_entrained - TCL >30 milliseconds. Among 23 pacing sites where PPI_entrained was unavailable, 7 of 8 NPP =3 pacing sites were on the circuit, whereas all 11 NPP >5 pacing sites were out of the circuit on the activation maps.

Conclusions: NPP obtained using a single mapping catheter may help identify a re-entrant AT circuit without directly confirming the establishment of entrainment pacing.

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.