Echo Doppler parameters predict response to cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) has been shown to reduce heart failure related morbidity and mortality. However, approximately 30% of patients do not respond to CRT. We investigated the usefulness of Echo Doppler parameters to predict reverse remodelling, functional improvement and mortality following CRT.

Our population consists of 200 consecutive heart failure patients evaluated for ventricular dyssynchrony by echocardiography between February 1999 and May 2007 who subsequently received CRT. Patients were reassessed for signs of reverse remodelling after a mean follow-up of 10 months. Information on vital status was obtained from local registration authorities.

Three parameters significantly predicted reverse remodelling in the logistic regression analysis: the Q-to-E-wave-delay (QED) at a cutoff of 550 ms (odds ratio 4.5, P-value 0.001), the interventricular mechanical delay (IVMD) at a cutoff of 60 ms (odds ratio 2.4, P-value 0.02), and the aortic electromechanical delay (A-EMD) at a cutoff of 140 ms (odds ratio 2.9, P-value 0.004). Furthermore, the QED and the IVMD also predicted all-cause mortality (hazard ratio 0.36, P-value 0.02 and 0.21, P-value 0.004, respectively). Adjustment for confounders did not alter the results.

The QED and IVMD predict reverse remodelling and survival following CRT. These parameters are easy to obtain, provide valuable prognostic information, and should thus be measured in CRT candidates evaluated by echocardiography.