Pre-implant global longitudinal strain as an early sign of pacing-induced cardiomyopathy in patients with complete atrioventricular block

Introduction: Long-term right ventricular pacing is the only treatment for patients with a complete atrioventricular block (CAVB); however, it frequently triggers ventricular dys-synchrony with left ventricular (LV) dysfunction. Previous studies showed that an early decline of LV global longitudinal strain (GLS) predicts pacing-induced LV dysfunction. We aimed to investigate the potential ability of the initial LV strain to predict pacing-induced cardiomyopathy (PICM) through long-term follow-ups. Methods: We retrospectively enrolled 80 patients with CAVB with normal LV function who were implanted with dual-chamber pacemakers between 2008 and 2018. Echocardiographic data and parameters (including longitudinal, radial, and circumferential strain based on speckle-tracking) were analyzed for the pre-implant (≤6 months) and post-implant periods. PICM was defined as a ≥10% reduction in the left ventricular ejection fraction (LVEF) resulting in an LVEF of <50% during the post-implant period. Predictors of PICM were identified using Cox proportional hazard models. Results: Patients who developed PICM were more likely to exhibit lower baseline LV GLS, as well as wider native and pacing QRS durations, than those who did not develop PICM (P =.016, P =.011, and P =.026, respectively). In the multivariate analysis, pre-implant LV GLS (hazard ratio: 1.27; 95% confidence interval 1.009–1.492; P =.004) was independently associated with the development of PICM. Conclusion: A lower baseline LV GLS predicts an increased risk of PICM. Patients with CAVB exhibiting low GLS are at increased risk of PICM. More frequent follow-up visits are warranted in these patients, who may also require de novo His-bundle pacing or an upgrade to biventricular pacing.