Effects of cardiac resynchronization therapy on left ventricular twist.

OBJECTIVES: This study explored the effects of cardiac resynchronization therapy (CRT) on left ventricular (LV) twist, particularly in relation to LV lead position.

BACKGROUND: LV twist is emerging as a comprehensive index of LV function.

METHODS: Eighty heart failure patients were included. Two-dimensional echocardiography was performed at baseline, immediately after CRT, and at 6-month follow-up. Speckle-tracking analysis was applied to assess LV twist. The LV lead was placed preferably in a (postero)lateral vein, and at fluoroscopy, the position was classified as basal, midventricular, or apical. Response to CRT was defined as reduction of LV end-systolic volume>or=15% at 6-month follow-up. A control group comprised 30 normal subjects.

RESULTS: Peak LV twist in heart failure patients was 4.8+/-2.6 degrees compared with 15.0+/-3.6 degrees in the control subjects (p<0.001). At 6-month follow-up, peak LV twist significantly improved only in responders (56%), from 4.3+/-2.4 degrees to 8.5+/-3.2 degrees (p<0.001). The strongest predictor of response to CRT was the improvement of peak LV twist immediately after CRT (odds ratio: 1.899, 95% confidence interval: 1.334 to 2.703, p<0.001). Furthermore, LV twist significantly improved in patients with an apical (from 4.3+/-3.1 degrees to 8.6+/-3.0 degrees, p=0.001) and midventricular (from 4.8+/-2.2 degrees to 6.4+/-3.9 degrees, p=0.038) but not with a basal (5.0+/-3.3 degrees vs. 4.1+/-3.2 degrees, p=0.28) LV lead position. Similarly, LV ejection fraction significantly increased in patients with an apical (from 26+/-7% to 37+/-7%, p<0.001) and midventricular (from 26+/-6% to 33+/-8%, p<0.001) but not with a basal (26+/-5% vs. 28+/-8%, p=0.30) LV lead position.

CONCLUSIONS: An immediate improvement of LV twist after CRT predicts LV reverse remodeling at 6-month follow-up.