Systolic Function Reserve Using Two-Dimensional Strain Imaging in Hypertrophic Cardiomyopathy: Comparison with Essential Hypertension

Background Although patients with hypertrophic cardiomyopathy (HCM) have normal ejection fractions at rest, the investigators hypothesized that these patients have differentially abnormal systolic function reserves, limiting their exercise capacity compared with patients with hypertension (HTN). Methods Forty patients with HCM (mean age, 39.1 ± 12 years), 20 patients with HTN with LVH, and 33 healthy individuals underwent resting and peak exercise echocardiography using two-dimensional strain imaging. Peak longitudinal systolic strain (εsys ) and strain rate were measured in apical views. Circumferential εsys and left ventricular (LV) twist were analyzed from short-axis views. LV systolic dyssynchrony was measured from regional longitudinal strain curves as the standard deviation of time to peak strain (time from the beginning of the Q wave on electrocardiography to peak εsys ) between 12 segments. The differences between resting and peak exercise values were analyzed, and functional reserve was calculated as the difference divided by the resting value. Results In patients with HCM, resting values for longitudinal εsys , systolic strain rate, early diastolic strain rate, and atrial diastolic strain rate were significantly lower, while circumferential εsys and twist were higher, compared with patients with HTN and controls ( P