Pennsylvania: In a large cohort of patients with reduced left ventricular ejection fraction requiring cardiac resynchronization therapy, scientists found that conduction system pacing showed a significant reduction in the composite outcome of all-cause mortality or heart failure hospitalization compared to traditional biventricular pacing. The article was published in the Heart Rhythm.
Cardiac resynchronization therapy with biventricular pacing is the cornerstone treatment for heart failure patients with ventricular dyssynchrony. Previous studies have demonstrated improved quality of life, reduced heart failure hospitalization, and decreased all-cause mortality with this therapy. Recently, a new concept, conduction system pacing with permanent pacing, including His bundle pacing and left bundle branch pacing, has been proposed as a safe and more physiological alternative to conventional biventricular pacing for cardiac resynchronization. It provides synchronous physiological ventricular activation with possible superior electrical and mechanical resynchronization compared to biventricular pacing However, studies evaluating the value of, conduction system pacing as an alternative approach to conventional biventricular pacing for cardiac resynchronization in heart failure patients are limited.

Vijayaraman P, Geisinger Commonwealth School of Medicine, Pennsylvania and colleagues initiated a study to compare the effects of conduction system pacing and conventional biventricular pacing on electrocardiographic and echocardiographic parameters as well as on clinical outcomes among patients undergoing Cardiac resynchronization therapy
For the study, researchers included 477 consecutive patients with left ventricular ejection fraction ≤35% and class I or II indications for Cardiac resynchronization therapy who underwent successful biventricular pacing(n- 219)or Conduction system pacing(n-258) at 2 major health care systems. The mean age was 72 ± 12 years, and the mean left ventricular ejection fraction was 26% ± 6%. Comorbidities included hypertension 70%, diabetes mellitus 45%, and coronary artery disease 52%. The primary outcome was set as the composite endpoint of time to death or heart failure hospitalization. Secondary outcomes included subgroup analysis in the left bundle branch block as well as individual endpoints of death and heart failure hospitalization.
Key findings of the study,
• Paced QRS duration in conduction system pacing was significantly narrower than biventricular pacing (133 ± 21 ms vs 153 ± 24 ms; P <.001).
• left ventricular ejection fraction improved in both groups during a mean follow-up of 27 ± 12 months and was greater after conduction system pacing compared to biventricular pacing (39.7% ± 13% vs 33.1% ± 12%; P <.001).
• The primary outcome of death or heart failure hospitalization was significantly lower with conduction system pacing vs biventricular pacing (28.3% vs 38.4%; HR- 1.52; P = .013).
The authors conclude that conduction system pacing improved clinical outcomes compared to biventricular pacing among patients with indications for cardiac resynchronization therapy. Conduction system pacing has proved to be non-inferior to biventricular pacing in echocardiographic, electrocardiographic, and clinical outcomes.
Reference:
Vijayaraman P, Zalavadia D, Haseeb A, Dye C, Madan N, Skeete JR, Vipparthy SC, Young W, Ravi V, Rajakumar C, Pokharel P, Larsen T, Huang HD, Storm RH, Oren JW, Batul SA, Trohman RG, Subzposh FA, Sharma PS. Clinical outcomes of conduction system pacing compared to biventricular pacing in patients requiring cardiac resynchronization therapy. Heart Rhythm. 2022 Aug;19(8):1263-1271. doi: 10.1016/j.hrthm.2022.04.023. Epub 2022 Apr 29. PMID: 35500791.