Presence of left ventricular contractile reserve, evaluated by means of dobutamine stress-echo test, is able to predict response to cardiac resynchronization therapy.

Introduction: We evaluated whether the dobutamine stress-echo test can select responders to cardiac resynchronization therapy (CRT). Up to 50% of patients do not respond to CRT. Lack of response may be due to a significant amount of scar or fibrotic tissue at myocardial level.

Methods And Results: We studied 42 CRT patients. After clinical and echocardiographic evaluation, all patients underwent a dobutamine stress-echo test to assess contractile reserve. Cut-off for the test was an increase of 25% of the left ventricular ejection fraction. Patients were implanted with a CRT-defibrillator and followed up at 6 months. Cut-off for CRT response was a reduction of 15% of left ventricular end-systolic volume. Twenty-five patients responded to CRT; all of them showed presence of contractile reserve. The test showed a sensitivity of 100% and a specificity of 88%.

Conclusion: Contractile reserve was a strong predictive factor of response to CRT in the studied population.