Abstract 4235: Abnormal Myocardial Deformation Is Associated With Mortality Independent Of Hypertrophy In The Absence of Ischemia
Purpose : Myocardial deformation has been shown to identify subclinical abnormalities in apparently normal hearts. We investigated the association of these markers with mortality after excluding ischemia in individuals undergoing dobutamine stress echocardiography (DSE).
Methods : We studied 163 consecutive patients with normal resting LV function and no ischemia at DSE. Mean Bethesda scores indicated a low ten-year risk of coronary disease (men 3.2±2.1%, women 5.3±2.6%). Relative wall thickness (RWT) and LVMI (indexed to height2.7) were calculated according to ASE guidelines. Customized software was used to measure peak systolic SR in 18 segments and mean global SR was calculated. Individuals were followed for all-cause mortality for a mean of 5.4±1.4 years.
Results : Mean RWT 0.46±0.11 (normal ≤ 0.42) and mean LVMI was 46.8±13.0g/m 2.7 (normal <51g/m 2.7). RWT and LVMI were assessed in the closest approximation to 1 standard deviation (per change of 0.1 for RWT and 10g/m2.7 for LVMI). In a Cox Proportional Hazards Model the strongest predictor of all-cause mortality was peak systolic SR (HR 3.72, 95%CI 1.8 –7.65, p<0.01). RWT (HR 1.4, 95%CI 1.0 –1.96, p<0.05) was a stronger predictor of all-cause mortality than LVMI (HR 1.2, 95%CI 0.86 –1.96, p=NS). Kaplan Meier curves were constructed by grouping the data into tertiles according to peak systolic SR (p<0.01 overall).
Conclusion : Peak systolic strain rate is a significant independent predictor of all-cause mortality, superior to LVMI and RWT. This link between myocardial deformation and outcome in the absence of myocardial ischemia may be consistent with an effect of interstitial changes on mortality.