Left Atrial Dyssynchrony in Patients With Nonobstructive Hypertrophic Cardiomyopathy Evaluated by Myocardial Strain Imaging

摘要

Background. The present study was conducted to examine left atrial (LA) dyssynchrony, determined by echocardiographic myocardial strain imaging, in patients with hypertrophic cardiomyopathy (HCM). Methods. We studied 26 patients with HCM (20 men and 6 women, age, 66±7 years) and 25 normal subjects (controls). Tissue Doppler-based strain images were recorded in the apical 2-, 4-chamber, and long-axis views. The LA strain curve was obtained with the region of interest placed at the 5 LA segments, namely, the atrial septum, lateral wall, inferior wall, anterior wall, and posterior wall. We measured standard deviation (SD) of the time-periods between aortic valve opening and maximal strain (reservoir dyssynchrony index) and SD of the time-periods between mitral valve opening and minimal strain (emptying dyssynchrony index).Results. Compared with controls, patients with HCM had greater indexes of reservoir (40±23 ms vs. 23±8 ms, p=0.001) and emptying (37±17 ms vs. 28±11 ms, p=0.02) dyssynchrony. Reservoir dyssynchrony (index >39 ms) was detectable in 11 patients, and emptying dyssynchrony (index >50 ms) was detectable in 5 patients. Patients with reservoir dyssynchrony had a greater LV mass index than those without (182±45 g/m2 vs. 142±32 g/m2, p=0.01), whereas patients with emptying dyssynchrony had greater LA minimal volume (39±12 ml/m2 vs. 26±10 ml/m2 p=0.02) and lower LA emptying fraction than those without (27±3% vs. 39±11%, p=0.02).Conclusions. LA dyssynchrony can be present throughout the cardiac cycle in patients with HCM. LA dyssynchrony is more common in the reservoir phase and may be attributed to significant myocardial involvement.