Delayed Enhancement Magnetic Resonance Imaging Predicts Response to Cardiac Resynchronization Therapy in Patients With Intraventricular Dyssynchrony Original Research Article

Objectives We evaluated the ability of delayed enhancement magnetic resonance imaging (DE-MRI) to predict clinical response to cardiac resynchronization therapy (CRT). Background Cardiac resynchronization therapy reduces morbidity and mortality in selected heart failure patients. However, up to 30% of patients do not have a response. We hypothesized that scar burden on DE-MRI predicts response to CRT. Methods The DE-MRI was performed on 28 heart failure patients undergoing CRT. Patients with QRS ≥120 ms, left ventricular ejection fraction ≤35%, New York Heart Association functional class II to IV, and dyssynchrony ≥60 ms were studied. Baseline and 3-month clinical follow-up, wall motion, 6-min walk, and quality of life assessment were performed. The DE-MRI was performed 10 min after 0.20 mmol/kg intravenous gadolinium. Scar measured by planimetry was correlated with response criteria. Results Twenty-three patients completed the protocol (mean age 64.9 ± 11.7 years), with 12 (52%) having a history of myocardial infarction. Thirteen (57%) patients met response criteria. Percent total scar was significantly higher in the nonresponse versus response group (median and interquartile range of 24.7% [18.1 to 48.7] vs. 1.0% [0.0 to 8.7], p = 0.0022) and predicted nonresponse by receiver-operating characteristic analysis (area = 0.94). At a cutoff value of 15%, percent total scar provided a sensitivity and specificity of 85% and 90%, respectively, for clinical response to CRT. Similarly, septal scar ≤40% provided a 100% sensitivity and specificity for response. Regression analysis showed linear correlations between percent total scar and change in each of the individual response criteria. Conclusions The DE-MRI accurately predicted clinical response to CRT. This technique offers unique information in the assessment of patients referred for CRT.