Presence of extensive LV remodeling limits the benefits of CRT in patients with intraventricular dyssynchrony.

Objectives The aim of this study was to evaluate whether, in patients with evidence of both electrical and mechanical left ventricular (LV) dyssynchrony, extensive LV dilation would affect response to cardiac resynchronization therapy (CRT). Background Cardiac resynchronization therapy is effective in heart failure patients with LV dysfunction and wide QRS complex. However, many patients still fail to respond. We hypothesized that presence of extensive LV dilation might prevent response to CRT, despite LV mechanical dyssynchrony. Methods We studied 78 heart failure patients (68 ± 9 years of age, 77% men) with both electrical (QRS width >120 ms) and mechanical intraventricular dyssynchrony (by tissue Doppler imaging and/or left lateral wall post-systolic contraction). Echocardiographic evaluation was performed at baseline and 6 to 8 months after CRT. As an indication of LV remodeling, end-diastolic volume index and end-systolic volume index (ESVI) and sphericity index were measured. Long-term (40 ± 23 months) clinical follow-up (events: cardiac death and hospital admission for heart failure) was also obtained. Results At follow-up after CRT, in the overall population, ejection fraction increased from 26 ± 6% to 35 ± 11% (p 2 to 119 ± 55 ml/m 2 ), ESVI (from 108 ± 37 ml/m 2 to 82 ± 49 ml/m 2 , p Conclusions In this nonrandomized, open-label clinical study, despite intraventricular electrical and mechanical dyssynchrony, extensive LV remodeling at baseline negatively impacted CRT results in terms of LV function improvement and incidence of cardiac events at follow-up.