Left Bundle Branch Area Pacing Improves Outcomes in Patients With Bradyarrhythmia

Left bundle branch area pacing (LBBAP), compared with right ventricular pacing, has excellent pacing parameters, better clinical outcomes, and preserves ventricular mechanical and electrical synchrony with no difference in complication rates. The findings were published in the International Journal of Cardiology.

While right ventricular pacing is accepted as the gold standard pacing method, it can be detrimental to mechanical and electrical dyssynchrony, possibly leading to increased heart failure hospitalization (HFH), atrial fibrillation (AF), and pacing induced cardiomyopathy. LBBAP is a viable alternative to achieve conduction system pacing, however the effects of LBBAP compared with right ventricular pacing have not been examined in a large study. Therefore, investigators sought to compare the efficacy and safety of LBBAP vs right ventricular pacing in patients with bradyarrhythmia and conduction system disorders. All-cause mortality, HFH, and AF were the primary outcomes.

The investigators conducted this systematic review and meta-analysis by searching the EMBASE, MEDLINE, and PubMed databases from inception until November 2022 for randomized controlled trials (RCTs) and observational studies. These studies compared LBBAP with right ventricular pacing in bradycardia or conduction system disorders in adult patients at least 18 years of age. They included 25 trials (N=4250 patients; 4 RCTs, 21 observational studies) in which a total of 2127 patients received LBBAP.

Across all studies, pacing indications were either atrioventricular block, sinus node dysfunction, or AF with a slow ventricular rate. Mean follow-up duration was 11.2 months (range, 0-29 months) with no between-group differences. Participants (mean age, 70.4 years; mean left ventricular ejection fraction, 60.58%) who received LBBAP had a mean procedural success rate of 93.6% and those who received right ventricular pacing had a mean success rate very near 100% (not all studies reported success rates).

Compared with right ventricular pacing, LBBAP was associated with lower risk for all-cause mortality (risk ratio [RR], 0.52; 95% CI, 0.34-0.80; P =.003; assessed in 3 studies, n=849 patients), HFH (RR, 0.33; 95% CI, 0.21-0.50; P <.001; assessed in 8 studies, n=1966 patients), and occurrence of AF (RR, 0.43; 95% CI, 0.27-0.68; P <.001; assessed in 2 studies, n=593 patients). There were no significant between-group differences in lead-related complications (P =.780; assessed in 20 studies).

LBBAP vs right ventricular pacing achieved better intraventricular mechanical synchrony (standard mean difference [MD], -1.77; 95% CI, -2.45 to -1.09; P <.001; I²=90%) and at follow-up, QRS duration was shorter in the LBBAP group vs right ventricular pacing group (weighted MD, -32.20 msec; 95% CI, -40.70 to -23.71; P <.001; I²=92%).

Pacing thresholds were similar between groups (P =.860), and the LBBAP group vs right ventricular pacing group had higher R wave amplitudes (P =.009).

Limitations of the analysis include the observational design of most included studies and the 4 RCTs are not sufficiently powered for all outcomes. Additionally, many studies have short follow-ups and there is very high heterogeneity in some of the outcomes.

“LBBAP is associated with significantly lower HFH, all-cause mortality, AF occurrence rates, and similar lead-related complication rates in comparison to RVP [right ventricular pacing] in patients with bradycardia and conduction system disorders,” the investigators wrote. “It achieves better electromechanical ventricular synchrony, low, and stable pacing thresholds, and high R-waves.”

Disclosure: Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures