Electrocardiographic repolarization changes following conduction system pacing in pacemaker-induced cardiomyopathy

Area of Science:

• Cardiology
• Electrophysiology
• Medical Devices

Background:

• Pacemaker-induced cardiomyopathy (PICM) results from chronic right ventricular pacing (RVP) causing left ventricular dysfunction.
• Left bundle branch area pacing (LBBAP) is a physiologic pacing strategy that can reverse PICM.
• The acute effects of LBBAP on ventricular repolarization in PICM are not well understood.

Purpose of the Study:

• To evaluate immediate repolarization changes after LBBAP in PICM patients.
• To compare repolarization responses in PICM patients undergoing LBBAP with a control group of non-ischemic dilated cardiomyopathy (DCM) patients.

Main Methods:

• Retrospective analysis of clinical, electrocardiographic, and pacing data from patients who received successful LBBAP.
• Manual measurement of baseline and post-implant ECG intervals (QT, QTc, Tp-Te) and qualitative assessment of T-wave memory (TWM).
• Recording of procedural parameters, success rates, and complications.

Main Results:

• Sixty patients were included (28 PICM, 32 DCM); baseline LVEF was higher in PICM.
• LBBAP success rates were similar between groups (93% vs. 96%).
• PICM patients had wider paced QRS and longer V6-V1 intervals, but repolarization metrics (QT, QTc, Tp-Te, TWM) showed no adverse changes and were comparable to DCM controls.

Conclusions:

• LBBAP does not induce unfavorable acute repolarization changes in PICM.
• Repolarization responses after LBBAP in PICM are comparable to those in DCM patients.
• LBBAP supports safety and demonstrates physiologic benefit for PICM upgrades.