P569Diastolic dyssynchrony is associated with exercise intolerance in hypertensive patients with left ventricular hypertrophy.

Abstract

Left ventricular hypertrophy (LVH) is associated with intra-ventricular dyssynchrony at systolic phase during exercise in hypertensive patients. However, dypsnea on exertion is much more correlated with diastolic phase. We investigated whether LVH is associated with diastolic dyssynchrony during exercise in patients with hypertension. Ninety hypertensive patients with exertional dyspnea and 30 control individuals were enrolled. Exercise stress echocardiography was performed using a symptom limited, multistage supine bicycle test. To evaluate the diastolic dyssynchrony of LV, we calculated the standard deviation (SD) of the averaged time from Q wave to myocardial early diastolic velocity in 12 segments. (TPe-SD, ms). Therefore, diastolic dyssynchrony index was SD of TPe. And also, we applied modified SD (SD/heart rate). There was no significant difference in systolic blood pressure (BP) and heart rate between the two groups. TPe-SD was significantly higher in patients with LVH at rest (27 ± 11.0 vs. 18.7 ± 7.4 ms, p<0.005) with exaggeration of the degree at peak exercise (42.0 ± 10.6 vs. 30.6 ± 12.4 ms, p<0.001). When applying modified SD, the difference is much more increased (80.0 ± 17.6 vs. 49.0 ± 21.3 ms, p <0.001). Multiple regression analysis showed LV mass index (β=0.515, P=0.001) and E/E' at peak exercise (β= -0.253, P=0.025) were independently associated with LV dyssynchrony during diastolic phase when controlled for age, sex, and systolic BP at peak exercise. Intra-ventricular diastolic dyssynchrony during exercise is significantly associated with exercise duration in hypertensive patients with LVH. And this result could explain that the patients with exertional dyspnea are more common in LVH group.