CI-452766-3 LEFT BUNDLE BRANCH AREA PACING IN PATIENTS WITH SEVERELY REDUCED LEFT VENTRICULAR EJECTION FRACTION

Abstract

Left bundle branch area pacing (LBBAP) has been used as an alternative to biventricular pacing (BiVp) to achieve cardiac resynchronization therapy (CRT). However, its use in patients with severely reduced left ventricular ejection fraction (LVEF) has not been described. To evaluate the outcomes of LBBAP compared to BiVp in patients with an LVEF ≦20%. In this multicenter study, consecutive adult patients with ischemic and non-ischemic cardiomyopathy and an LVEF <35% undergoing CRT were included. LBBAP was offered as a first line treatment strategy after thorough discussion with patients; the last consecutive patients in whom BiVp was performed were used as controls. Patients were analyzed according to their LVEF (≤20% vs. 21-35%) and the pacing strategy used (LBBAP vs BiVp). The primary outcome was a composite of HF-related hospitalization and all-cause mortality. Secondary outcomes included individual components of the primary outcome, procedural and fluoroscopy times, paced QRS duration, change in LVEF, final LVEF, and change in HF-related symptoms. A total of 342 patients (mean age 69.7±11.2, female 30.1%; 117 with LVEF ≤20%) were included. No significant differences in the primary outcome or HF-related hospitalization were found in patients with LVEF ≤20% compared to patients with an LVEF 21-35%, but patients with a baseline LVEF ≤20% had a higher all-cause mortality (OR: 2.35; 95%CI 1.018-5.436, p=0.047). There were no differences in the primary outcome in patients with LVEF ≤20% treated with LBBAP vs. BiVp. However, patients with an LVEF ≤20% treated with LBBAP had significantly lower fluoroscopy times (17.5±10.3 vs. 23.1±15.4 mins., p=0.03), shorter paced QRS durations (124.6±18.7 vs. 151.1±34.3 msec, p<0.001), greater improvements in LVEF (8.1±11.2 vs. 3±5.7%, p=0.011), higher final LVEF (26.7±12.9 vs. 21.1±7.2%, p=0.018) and were less symptomatic (NYHA class 1.83±0.93 vs. 2.27±0.88, p=0.018) than patients treated with BiVp, respectively. A baseline LVEF ≤20% was associated with significantly longer procedural and fluoroscopy times in patients undergoing LBBAP compared to a baseline LVEF 21-35%. Patients with a baseline LVEF ≤20% have a higher all-cause mortality than patients with an LVEF 21-35%. Patients with an LVEF ≤20% treated with LBBAP have lower fluoroscopy time, shorter paced QRS duration, significantly less HF related symtpoms, greater changes and higher final LVEF than patients treated with BiVp.