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

Heart Rhythm. 2010 Nov;7(11):1600-5. doi: 10.1016/j.hrthm.2010.07.036. Epub 2010 Aug 3.


Background: 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.

Objective: 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.

Methods: 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%.

Results: 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%.

Conclusion: The DSE test in CRT candidates is safe and feasible. LVCR presence at baseline increases the chances of response to CRT.

Publication types

  • Clinical Trial, Phase I

MeSH terms

  • Aged
  • Cardiac Resynchronization Therapy*
  • Echocardiography, Stress
  • Feasibility Studies
  • Female
  • Heart Ventricles / diagnostic imaging*
  • Heart Ventricles / physiopathology*
  • Humans
  • Male
  • Middle Aged
  • Myocardial Contraction*
  • Sensitivity and Specificity