Background: This multicenter prospective cohort study aimed to identify both ability of echocardiographic parameters to detect cardiac resynchronization therapy (CRT) volume responders and relation of these parameters with clinical outcomes.
Methods and results: CRT responder was defined as ≥ 15% reduction of left ventricular (LV) end-systolic volume at 6 months. Seven echocardiographic dyssynchrony parameters were evaluated. The clinical endpoint comprised time to death from any cause or unplanned hospitalization for a major cardiovascular event. Of the 217 patients enrolled, 63 percent were classified as volume responders, in whom significantly fewer events occurred than in non-responders (log rank, P < 0.001). No single echocardiographic criterion had significant power to detect volume responders, but a combining measurement of dyssynchrony between septum and LV free wall with M-mode and tissue Doppler imaging was independently associated with volume responders. In addition, this combined parameter was associated with the endpoint (hazard ratio, 0.66, 95% confidence interval 0.30-0.98, P = 0.04). In contrast, left bundle branch block was identified as an independent predictor of volume responders and more strongly associated with the endpoint (hazard ratio, 0.38, 95% confidence interval 0.20-0.72, P = 0.003).
Conclusions: Echocardiographic parameters did not show significant power to detect CRT responders independently.