Presence of left ventricular contractile reserve predicts midterm response to cardiac resynchronization therapy—results from the LOw dose DObutamine Stress-Echo Test in Cardiac Resynchronization Therapy (LODO-CRT) Trial

Abstract

Cardiac resynchronization therapy (CRT) is effective in selected patients with heart failure (HF). Nevertheless, the nonresponder rate remains high. The low-dose dobutamine stress-echo (DSE) test detects the presence of left ventricular (LV) contractile reserve (LVCR) in HF patients of any etiology and may be useful in predicting response to resynchronization. The purpose of this study was to present the results of the LODO-CRT trial, which evaluated whether LVCR presence at baseline increases the chances of response to CRT. LODO-CRT is a multicenter prospective study that enrolled CRT candidates according to guidelines. LVCR presence was defined as an LV ejection fraction increase >5 units during DSE test. CRT response is assessed at 6-month follow-up as an LV end-systolic volume reduction ≥10%. Two hundred seventy-one patients were enrolled. The DSE test was feasible without complications in 99% of patients. Nine patients died from noncardiac disease, and 31 presented inadequate data. Two hundred thirty-one patients were included in the analysis. Mean patient age was 67 ± 10 years; 95% were in New York Heart Association class III, and 42% had HF of ischemic etiology. Mean QRS and LV ejection fraction were 147 ± 25 ms and 27% ± 6%, respectively. LVCR presence was found in 185 subjects (80%). At follow-up, 170 (74%) patients responded to CRT, 145/185 in the group with LVCR (78%) and 25/46 (54%) in the group without LVCR. Difference in responder proportion to CRT was 24% (P <.001). Reported test sensitivity is 85%. The DSE test in CRT candidates is safe and feasible. LVCR presence at baseline increases the chances of response to CRT.