Abstract 15093: Prediction of Response to Cardiac Resynchronization Therapy Using Improvement of Coronary Flow Reserve in Patients with Non-Ischemic Cardiomyopathy
Background: Left bundle branch block (LBBB) or permanent right ventricular pacing induces mechanical dyssynchrony, which leads to deterioration of coronary flow dynamics. This study sought to investigate whether the effect of cardiac resynchronization therapy on coronary flow reserve can predict echocardiographic response in patients with non-ischemic cardiomyopathy.
Methods: 18 patients with non-ischemic cardiomyopathy (64.1 ± 2.5 years old, 16 males, NHYA class 3.1 ± 0.2, QRS duration 171 ± 6 ms, ejection fraction 29.7 ± 2.2%, LBBB in 10 and complete atrioventricular block (CAVB) in 8) were enrolled. One week after CRT device implantation, coronary flow velocity and coronary flow reserve (CFR) in left anterior descending coronary artery were measured by using a pressure and Doppler velocity guidewire, during 2 programming modes: ‘Control’ is defined as atrial pacing in patients with LBBB or sequential atrial and right ventricular pacing in patients with CAVB, and ‘BiV’ is defined as sequential atrial and biventricular pacing. During two programming modes, coronary flow velocity was measured before and after adenosine triphosphate administration. Patients underwent echocardiographic evaluation before CRT and 6 month after CRT. Response to CRT is defined as relative change in left ventricular end-systolic volume ≥ 15%.
Result: CFR during Control and BiV were not significant parameters to predict response to CRT. However, delta CFR (CFR during BiV minus CFR during Control) was predictive of response to CRT with sensitivity of 75%, specificity of 83%, and area under the curve (AUC) of 0.85 (P = 0.02). Furthermore, delta CFR was the better predictor than echocardiographic parameters, intraventricular mechanical delay (AUC 0.65, P = 0.33) and radial dyssynchrony by speckle-tracking strain (AUC 0.78, P = 0.08).
Conclusion: CRT has a beneficial effect on coronary flow circulation and improvement in CFR might be associated with reverse remodeling following CRT.
- © 2012 by American Heart Association, Inc.