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

BACKGROUND Cardiac resynchronization therapy (CRT) is effectivein selected patients with heart failure (HF). Nevertheless, thenonresponder rate remains high. The low-dose dobutamine stressecho(DSE) test detects the presence of left ventricular (LV)contractile reserve (LVCR) in HF patients of any etiology and maybe useful in predicting response to resynchronization.OBJECTIVE The purpose of this study was to present the results ofthe LODO-CRT trial, which evaluated whether LVCR presence atbaseline increases the chances of response to CRT.METHODS LODO-CRT is a multicenter prospective study that enrolledCRT candidates according to guidelines. LVCR presence wasdefined as an LV ejection fraction increase 5 units during DSEtest. CRT response is assessed at 6-month follow-up as an LVend-systolic volume reduction 10%.RESULTS Two hundred seventy-one patients were enrolled. TheDSE test was feasible without complications in 99% of patients.Nine patients died from noncardiac disease, and 31 presentedinadequate data. Two hundred thirty-one patients were includedin the analysis. Mean patient age was 67 10 years; 95% were inNew York Heart Association class III, and 42% had HF of ischemicetiology. Mean QRS and LV ejection fraction were 147 25 ms and27% 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 groupwithout LVCR. Difference in responder proportion to CRT was 24%(P .001). Reported test sensitivity is 85%.CONCLUSION The DSE test in CRT candidates is safe and feasible.LVCR presence at baseline increases the chances of response toCRT.