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 ≥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° compared with 15.0 ± 3.6° 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° to 8.5 ± 3.2° (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° to 8.6 ± 3.0°, p = 0.001) and midventricular (from 4.8 ± 2.2° to 6.4 ± 3.9°, p = 0.038) but not with a basal (5.0 ± 3.3° vs. 4.1 ± 3.2°, 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. © 2009 American College of Cardiology Foundation.