Incidence and Clinical Outcomes of Pacing Induced Cardiomyopathy in Patients With Normal Left Ventricular Systolic Function and Atrioventricular Block

Patients with preserved left ventricular (LV) ejection function (EF) and atrioventricular block (AVB) who are anticipated for high-burden of right ventricular (RV) pacing possess a risk to develop pacing-induced cardiomyopathy (PIC) and adverse clinical outcomes. Hence, the aim of the study is to evaluate the incidence, predictors, and clinical outcomes of RV PIC in patients with preserved LVEF, AVB, and high-burden of RV pacing. One thousand and thirteen patients with second or third-degree AVB underwent first time pacemaker implantation between January 2002 and August 2016. A total of 203 patients with a newly implanted pacemaker, normal baseline LVEF, and high burden of RV pacing were included in the present study. Follow-up echocardiography was examined for a new decrease in LVEF of 10% or higher. Alternative causes for cardiomyopathy were ruled out. Patient characteristics, echocardiographic measurements, device clinic data, mortality, and hospitalizations for heart failure were collected and compared between the PIC and the non-PIC groups. Fifty-one patients (25%) developed LV dysfunction with 22 patients (11%), showing LVEF < 40%. During a mean follow-up of 49.2 months, the risk of heart failure hospitalization or all-cause mortality was significantly higher in the PIC group versus non-PIC group (35.3% vs 19.1%, p = 0.009). In conclusion the incidence of PIC in patients with normal LVEF and AVB, who are anticipated for high-burden of RV pacing is high. PIC in patients with a previously normal LV function is associated with unfavorable long-term clinical outcomes, including higher rates of heart failure hospitalizations and all-cause mortality.