Abstract 12176: Feature of Mechanical Left Ventricular Dyssynchrony in Heart Failure Patients with "Very" Narrow QRS Duration: Using Three-dimensional Speckle-tracking Study
Background: Mechanical left ventricular (LV) dyssynchrony was seen even in heart failure (HF) patients with narrow QRS duration (<120ms), and such patients can respond for cardiac resynchronization therapy (CRT). However, the feature of mechanical LV dyssynchrony in HF patients with “very” narrow QRS duration (<100ms) remains unknown.
Methods: We studied 101 subjects, consisted of 23 HF patients with LV ejection fraction (EF) <35% and “very” narrow QRS duration (<100ms), 23 HF patients with LVEF<35% and “borderline” narrow QRS duration (100-120ms), 30 HF patients with LVEF <35% and “wide” QRS duration (>120ms), and 25 normal controls. LV dyssynchrony was evaluated as the standard deviation of time-to-peak area strain (endocardial area change ratio), and area strain dyssynchrony index (ASDI) from 16 LV segments with 3-dimensional speckle-tracking echocardiography. ASDI >3.8% was pre-defined as significant.
Results: The standard deviation of time-to-peak area strain and ASDI in patients with “very” narrow QRS duration was significantly lower than those in patients with “borderline” narrow and “wide” QRS duration (79±29 vs. 108±46 and 141±38ms, p<0.01 and <0.001, and 1.8±1.2 vs. 2.5±1.2 and 3.9±1.4%, p<0.05 and <0.001), but higher than those in normal controls (79±29 vs. 40±21ms and 1.8±1.2 vs. 0.7±0.5%, both p<0.001). QRS duration was weak, but significantly correlated with the standard deviation of time-to-peak area strain and ASDI (r=0.51 and 0.56, both p<0.001) in HF patients. Furthermore, the prevalence of significant ASDI in HF patients with “very” narrow QRS duration was 17% (4/23), and lower than that with “wide” QRS duration (vs.50%, p<0.05), but higher than that with normal controls (vs.0%, p<0.05).
Conclusions: Though small, some HF patients with “very” narrow QRS duration had significant mechanical LV dyssynchrony. These findings suggest that even HF patients with “very” narrow QRS duration may be considered as potential candidates for CRT.
- © 2012 by American Heart Association, Inc.