Are the Extent, Location, and Score of Segmental Wall Motion Abnormalities Related to Cardiac Resynchronization Therapy Response?

Abstract

We hypothesized that segmental wall motion abnormalities (WMAs) are related to cardiac resynchronization therapy (CRT) response. We studied 108 patients who received CRT, 69 with ischemic and 39 with nonischemic heart disease. A wall motion score index (WMSI) was analyzed using a 17-segment model and calculated by the total score/number of segments analyzed. A decrease of left ventricular end systolic volume > or =15% after CRT was defined as a positive response to CRT. Of 108 patients, 1,054/1,836 segments (57%) had WMAs. The mean WMSI was 2.06 in patients with ischemic heart disease and 1.04 in patients with nonischemic heart disease (P < 0.0001). The area under the receiver operating characteristic curve for a WMSI predicting a positive response to CRT was 0.70 (P = 0.0001). The cutoff point was a WMSI < or =2 for prediction of a positive response to CRT. After adjustment for age, gender, and clinical features, the WMSI persistently related to CRT responders (P = 0.01). During 15-month follow-up, the percentage of CRT nonresponders in patients with a WMSI >2 was significantly higher (82%) compared to patients with a WMSI < or =2 (47%, P = 0.005) and nonischemic heart disease (36%, P < 0.001). In 59 patients with left ventricular mechanical dyssynchrony, the percentage of negative responders to CRT in patients with a WMSI >2, < or =2, and nonischemic heart disease were 53% (8 of 15), 16% (3 of 19) and 0% (0 of 25), respectively (P < 0.001). A large extent of WMAs and a WMSI >2 predicted a poorer CRT response.