His-Purkinje Conduction System Pacing Optimized Trial of Cardiac Resynchronization Therapy vs Biventricular Pacing: HOT-CRT Clinical Trial.

BACKGROUND: His-Purkinje conduction system pacing (HPCSP) using His bundle pacing (HBP) or left bundle branch pacing (LBBP) has emerged as an alternative to biventricular pacing (BVP) in patients requiring cardiac resynchronization therapy (CRT). OBJECTIVES: The aim of the study was to compare the feasibility and clinical efficacy of HOT-CRT (His-Purkinje conduction system pacing Optimized Trial of Cardiac Resynchronization Therapy) with BVP in patients with heart failure, reduced ejection fraction, and indication for CRT. METHODS: This was a prospective, randomized, controlled trial of HOT-CRT and BVP in patients with LVEF <50% and indications for CRT. If HPCSP resulted in incomplete electrical resynchronization, a coronary sinus (CS) lead was added. The primary outcome was the change in left ventricular ejection fraction (LVEF) at 6 months. The primary safety endpoint was freedom from major complications. RESULTS: A total of 100 patients (female 31%, aged 70 ± 12 years, LVEF 31.5% ± 9.0%) were randomized. HOT-CRT was successful in 48 of 50 (96%) and BVP-CRT in 41 of 50 (82%) patients (P = 0.03). QRS duration significantly decreased from 164 ± 26 ms to 137 ± 20 ms with HOT-CRT and 166 ± 28 ms to 141 ± 19 ms with BVP. Fluoroscopy results (18.8 ± 12.4 min vs 23.8 ± 12.4 min, P = 0.05) and procedure duration (119 ± 42 min vs 114 ± 36 min, P = 0.5) were similar. The primary outcome of change in LVEF at 6 months was greater in HOT-CRT than in BVP (12.4% ± 7.3% vs 8.0% ± 10.1%, P = 0.02). The primary safety endpoint was similar (98% vs 94%, P = 0.62). Echocardiographic response of improvement in LVEF >5% occurred in 80% vs 61% (P = 0.06). Complications occurred in 3 (6%) in HOT-CRT vs 10 (20%) in BVP (P = 0.03). CONCLUSIONS: HPCSP-guided CRT resulted in greater change in LVEF compared with BVP. Randomized clinical trials with long-term follow-up are necessary. (His-Purkinje Conduction System Pacing Optimized Trial of Cardiac Resynchronization Therapy [HOT-CRT]; NCT04561778).

Non-invasive assessment of ventricular electrical heterogeneity to optimize left bundle branch area pacing.

BACKGROUND: Left bundle branch area pacing (LBBAP) is a novel therapeutic option for bradycardia and heart failure patients. ECG belt is a novel technology for assessment of ventricular electrical heterogeneity (VEH) using multi-electrode ECG. A metric of overall VEH based on standard deviation of activation times (SDAT) from all electrodes in the ECG belt has been previously shown to predict cardiac resynchronization therapy (CRT) response. The aim of the study is to evaluate non-invasive assessment of VEH using ECG belt to optimize LBBAP. METHODS: VEH from a 40-electrode ECG belt was characterized in 20 patients (male 15, EF 33 ± 13%, NYHA class 3.05 ± 0.6; CRT indication 18) during LBBAP (20) and LBBAP-Optimized CRT (LOT-CRT-7), anodal capture (16), NS-LBBP (18), S-LBBP (5), LVSP (9). In addition to SDAT, regional (LV/RV) VEH was assessed with average left ventricular activation times (LVAT), SDAT of left-sided (LV dispersion) and right-sided (RV dispersion) electrodes. Optimal LBBAP was determined based on maximal SDAT and QRS duration (d) change. RESULTS: All metrics were significantly reduced (p < 0.0001 for ECG belt metrics, p = 0.0027 for QRSd) during LBBAP and LOT-CRT compared to intrinsic. QRSd, SDAT, LVAT, and LV and RV dispersion during optimal LBBAP were significantly lower (133 ± 20/157 ± 24; 20.5 ± 7.5/38.6 ± 9; 44.4 ± 14.3/61.4 ± 21; 11.6 ± 11.6/29.5 ± 15; 21.1 ± 7.8/42.5 ± 9.3; p < 0.0001) compared to intrinsic rhythm. However, they were not significantly different among selective, non-selective, anodal, and LV septal captures. EF and NYHA class improved to 46 ± 11% and 1.9 ± 0.6 (p < 0.001). CONCLUSIONS: LBBAP significantly reduced overall and regional (RV/LV) VEH, irrespective of the mechanism of capture. Detailed assessment of electrical heterogeneity using ECG belt may add valuable insights on effects of LBBAP. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04583709.