الفهرس | Only 14 pages are availabe for public view |
Abstract Objectives: Right ventricular(RV), adaptive mechanisms in hypertrophic cardiomyopathy (HCM) is poorly understood. We attempted to assess RV deformation response to exercise in HCM and its relationship to LV function, using vector velocity imaging (VVI). Methods: resting and exercise echocardiography was performed in 40 consecutive HCM patients (41±19 years; 58% male) and 33 age and sex matched healthy control. Longitudinal peak systolic strain(εsys), strain rate[SRsys, SRe, SRa] of RV segments from apical four-chamber view were used to evaluate RV functional reserve (stress-rest/rest). Similar parameters were quantified in LV wall segments. Intra-V dyssynchrony was defined as SD of TTP (measured from regional strain curves for each segment, as time from beginning of Q wave to time to peak εsys). Results: In HCM and immediately postexertion, RV εsys (-18.5±10 versus -28.2±5 P<0.001) and SRsys (-1.7±1.2versus -2.7±0.6s-1 P<0.0001) was significantly lower and RV dyssynchrony (73.9±33versus 28.4±12 ms, P<0.0001) was greater compared with control subjects. A significant correlation was evident between exercise capacity and RV TTP-SD, r=- .32, P<.04 and RV SR sys (r=.34 , P<.03). RV functional systolic reserve showed direct relationship to LV systolic functional reserve, r=.32, P<.04. However, using multivariate regression analysis, LV SRsys and LV TTPSD is the only predictor of exercise capacity. While RV functional reserve did not change the outcome. Exercise stress induced RV dysfunction in HCM is associated with exercise intolerance and strongly related to LV deformation abnormalities as evaluated by VVI. Conversely, LV systolic parameters remain the most important indicators linked to exercise capacity in this population. |