Low-dose dobutamine test associated with interventricular dyssynchrony: a useful tool to identify cardiac resynchronization therapy responders: data from the LOw dose DObutamine stress-echo test in Cardiac Resynchronization Therapy (LODO-CRT) phase 2 study

Am Heart J. 2012 Mar;163(3):422-9. doi: 10.1016/j.ahj.2011.11.015. Epub 2012 Jan 20.


Background: Cardiac resynchronization therapy (CRT) is effective in patients with heart failure, but 30% to 50% of subjects are classified as nonresponders. Identifying responders remains a challenging task.

Aims: The LODO-CRT trial investigated the association between left ventricular contractile reserve (LVCR) and clinical and echocardiographic long-term CRT response.

Methods: This is a multicenter, prospective, observational study. Left ventricular contractile reserve was detected using a dobutamine stress echocardiography test, defined as an ejection fraction increase of >5 points. Clinical CRT response was defined as the absence of major cardiovascular events (ie, cardiovascular death or heart failure hospitalization). Echocardiographic response was defined as a left ventricle end-systolic volume reduction of >10%.

Results: A total of 221 CRT-indicated patients were studied (80% presented LVCR). During a mean follow-up of 15 ± 5 months, 17 patients died and 16 were hospitalized due to heart failure. The proportion of clinical responders was 155 (88%) of 177 and 33 (75%) of 44 (P = .036) in the groups with and without LVCR, respectively. Kaplan-Meier analysis showed a significant difference in cardiac survival/hospitalization between patients with and without LVCR. The proportion of echocardiographic responders was 144 (87%) of 166 and 16 (42%) of 38 in the groups with and without LVCR (P < .001), respectively; LVCR showed 90% sensitivity and 87% positive predictive value to prefigure echocardiographic CRT responders. Multivariable analysis identified LVCR and interventricular dyssynchrony as independent predictors of CRT response. The concomitant presence of both factors showed 99% specificity and 83% sensitivity in detecting responders.

Conclusion: The presence of LVCR helps in predicting a clinical and echocardiographic CRT response. Concomitant assessment of LVCR and interventricular dyssynchrony accurately stratifies responder and nonresponder patients.

Publication types

  • Clinical Trial, Phase II
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial

MeSH terms

  • Aged
  • Cardiac Resynchronization Therapy / methods*
  • Cardiotonic Agents / administration & dosage
  • Dobutamine*
  • Dose-Response Relationship, Drug
  • Echocardiography, Stress / methods*
  • Female
  • Follow-Up Studies
  • Humans
  • Male
  • Prospective Studies
  • Sensitivity and Specificity
  • Severity of Illness Index
  • Stroke Volume / physiology*
  • Tachycardia, Ventricular / diagnostic imaging
  • Tachycardia, Ventricular / physiopathology
  • Tachycardia, Ventricular / therapy*
  • Time Factors
  • Ventricular Remodeling*


  • Cardiotonic Agents
  • Dobutamine