Predictors of right ventricular pacing-induced left ventricular dysfunction in pacemaker recipients with preserved ejection fraction.

Background: Pacing is an effective treatment in the management of patients with bradyarrhythmias. Chronic right ventricular pacing may cause electrical and mechanical dyssynchrony leading to a deterioration of left ventricular ejection fraction (LVEF). This deterioration of LVEF has been described as pacing-induced cardiomyopathy (PICM). The incidence of PICM has been described by many studies, ranging between 10% and 26%. Predictors for PICM are not yet established-studies were limited by variations in the definition of PICM and the follow-up period. The authors studied the incidence and predictors of PICM in patients with preserved LVEF who underwent pacemaker implantation.

Methods: This retrospective study included 320 patients that underwent single- or dual-chamber pacemaker implantation, with a mean follow up period of 4.7 ± 2.0 years. Implantable cardioverter defibrillator and cardiac resynchronization therapy patients were excluded from this study. Individuals that had a baseline LVEF ≥ 50% before implantation in transthoracic echocardiography were included in the study.

Results: Of the 320 patients included in the study, 45% were male, with a mean age 55.5 years. The incidence of PICM was 7.5%. Wider native QRS duration, particularly > 140 ms (P < 0.001), wider paced QRS (pQRS) duration > 150 ms (P < 0.001), low normal ejection fraction < 56% pre-implantation (P = 0.023) and increased LV end diastolic diameter (LVEDD) > 53 mm and LV end systolic diameter (LVESD) > 38 mm (P < 0.001) predicted the development of PICM. There was no association between burden of right ventricular pacing (P = 0.782) or pacing site (P = 0.876) and the development of pacemaker-induced cardiomyopathy.

Conclusions: Right ventricular pacing-induced left ventricular dysfunction is not uncommon, with an incidence of 7.5%. Wider native and paced QRS durations, low normal ejection fraction (< 56%) pre-implantation and increased LVEDD and LVESD post implantation are the most important predictors for the development of PICM.