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.