Introduction: Frequent right ventricular (RV) pacing can lead to a decline in left ventricular (LV) function.
Hypothesis: This study aimed to identify echocardiographic predictor of RV pacing-induced cardiomyopathy (PICM).
Methods: We retrospectively studied 131 consecutive patients undergoing pacemaker implantation for atrioventricular block between 2005 and 2015. Patients were included if baseline LV ejection fraction (EF) was normal, single-chamber ventricular or dual-chamber pacemaker (but not implantable cardioverter-defibrillator or biventricular pacemaker) was implanted and echocardiogram was available before(≤6 months) and after implantation. We measured longitudinal, radial and circumferential strain using speckle tracking echocardiography before implantation. PICM was defined as ≥10% decreased in LVEF, resulting in LVEF <50%. Patients with alternative causes of cardiomyopathy were excluded. Predictors of the development of PICM were identified using multivariate Cox proportional hazards modeling.
Results: Of 43 patients meeting study criteria, 17 (25.8%) developing PCIM, with a decreased in mean LVEF from 67.1% to 40.1% over a mean follow-up period of 4.8 years. Those who developed PICM were more likely to use diuretics, with lower baseline LV global longitudinal strain and wider native and pacing QRS duration (P=0.045, P=0.001, P=0.048 and P=0.024, respectively). In multivariate analysis, LV global longitudinal strain (hazard ratio 1.179 ; 95% confidence interval 1.005-1.383; P=0.043) and wider pacing QRS duration (hazard ratio 1.029; 95% confidence interval 1.002-1.057; P=0.037) were independently associated with the development of PICM.
Conclusions: Risk for PICM begins in subclinical LV systolic dysfunction. Patients with low global longitudinal strain and wider pacing QRS duration are at increased risk. These patients warrant closer follow-up with a lower threshold for biventricular pacing.