Comparison of electrocardiographic parameters between left bundle optimized cardiac resynchronization therapy (LOT-CRT) and left bundle branch pacing-cardiac resynchronization therapy (LBBP-CRT).

Abstract

In patients undergoing cardiac resynchronization therapy using left bundle branch area pacing (LBBP-CRT), the addition of a coronary sinus lead, that is, Left bundle optimized CRT (LOT-CRT) might confer additional benefits. To compare the electrocardiographic characteristics between LBBP-CRT and LOT-CRT MATERIALS AND METHODS: Patients with non-ischemic cardiomyopathy (NICMP) and left bundle branch block (LBBB) with left ventricular ejection fraction<35% who underwent implantation of an atrial lead, a left bundle lead, and a coronary sinus lead were included in this prospective study. Digital 12-lead electrocardiograms were recorded in three pacing modes-AAI, DDD with pacing from the LBB lead (LBBP-CRT), and DDD with pacing from both left bundle and coronary sinus leads (LOT-CRT). QRS duration (QRSd), QRS area, QT interval, and T peak-T end (TpTe) intervals were compared. Among 24 patients, QRSd reduced from 167±21.2ms to 134.5±23.6ms with LBBP-CRT (p<.001) and 129.5±18.6ms with LOT-CRT (p<.001) without a significant difference between LBBP-CRT and LOT-CRT (p=.15). Patients with QRS duration with LBBP-CRT>131ms showed a significant reduction in QRSd with LOT-CRT (p=.03). QT interval was reduced with both modes of CRT. LOT-CRT was associated with a greater reduction in QRS area (p=.001), TpTe interval (p=.03), and TpTe/QT ratio (p=.013) compared to LBBP-CRT. In patients with NICMP and LBBB, there was no significant difference in QRSd with LOT-CRT compared to LBBP-CRT. However, in patients with QRSd>131ms after LBBP-CRT, LOT-CRT resulted in a significantly narrower QRS.