Early pacing-induced systolic dyssynchrony is a strong predictor of left ventricular adverse remodeling: Analysis from the Pacing to Avoid Cardiac Enlargement (PACE) trial

Abstract Background Right ventricular apical (RVA) pacing is associated with adverse left ventricular (LV) remodeling and biventricular (BiV) pacing may prevent it although the mechanisms remain unclear. The current study aimed to assess the role of early pacing-induced systolic dyssynchrony (DYS) to predict adverse LV remodeling. Methods Patients with standard pacing indications and normal LV ejection fraction were randomized either to BiV (n=89) or RVA pacing (n=88). Pacing-induced DYS, defined as the standard deviation of the time to peak systolic velocity (Dyssynchrony Index) >33ms in a 12-segmental model of LV, was measured by tissue Doppler echocardiography at 1month. Results At 1month, 59 patients (33%) had DYS which was more prevalent in RVA than BiV pacing group (52% vs. 15%, χ 2 =28.3, p 2 =40.8, p Conclusion Early pacing-induced DYS is a significant predictor of LV adverse remodeling and the observed benefit of BiV pacing may be related to the prevention of DYS. Clinical trial registration Centre for Clinical Trials number, CUHK_CCT00037 (URL: http://www.cct.cuhk.edu.hk/Registry/publictrialrecord.aspx?trialid=CUHK_CCT00037).