Low-dose dobutamine stress echo for reverse remodeling prediction after cardiac resynchronization

Abstract

Purpose: Cardiac resynchronization therapy (CRT) is a valuable option for patients with heart failure and wide QRS to reduce electromechanical dyssynchrony (DYS). High non-responders rate (30%) urges the need to improve selection of candidates for CRT. We hypothesized that low-dose dobutamine stress echocardiography (DSE) can help unmask dyssynchronous motion. The aim of this study is comparison between dyssynchrony index at rest and during low-dose dobutamine stress to predict left ventricular reverse remodeling after CRT.

Patients and methods: Prospectively, 57 consecutive patients (37 male) aged 61.8±9 who qualified for CRT according to current guidelines were enrolled. Two dimensional echocardiography and tissue Doppler imaging (TDI) were performed before and 6 month after CRT to assess reverse remodeling (rLV). Additionally DSE was performed before CRT. DYS was assessed at rest (DYSr) and peak DSE (DYSd) separately, as a difference between time to peak systolic velocity (Ts) of septum and lateral wall. Ts was corrected for heart rate.

Results: rLV defined as decrease ≥15% of LVESV at follow-up was found in 38 (67%) patients. DYSr and DYSd were independent predictors of rLV (OR=1.04, Cl ±1.02-1.06, p<0.02 and OR=1.05, Cl±1.03-1.08, p<0.0002 respectively). ROC analysis found that DYSr>42ms and DYSd>59ms had sensitivity of 70% and 87%, specificity of 61% and 78%, and accuracy of 70% and 84% respectively for prediction of reverse remodeling LV. Area under Receiver Operating Characteristic Curve for DYSd was higher than for DYSr (0.89 vs 0.71, p<0.007).

Conclusion: Exercise intraventricular dyssynchrony assessed by dobutamine stress echo is a strong independent predictor of cardiac resynchronization therapy response.

Keywords: Dobutamine stress echocardiography; Responders for CRT; Resynchronization.