Midwall Left Ventricular Mechanics

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Abstract
Background An appreciable proportion of asymptomatic hypertensive patients have depressed left ventricular (LV) performance that is identified by midwall shortening/end-systolic stress relations but not by indexes that use endocardial shortening. It has not been established, however, whether depressed midwall ventricular performance has prognostic implications. Methods and Results Echocardiographic endocardial and midwall LV fractional shortening/circumferential end-systolic stress relations in 294 hypertensive patients were analyzed as predictors of the occurrence of cardiovascular morbid events that occurred in 50 patients (including 14 deaths) during a 10-year mean follow-up. Patients with initially lower midwall but not endocardial shortening, either in absolute terms or as a percentage of predicted from observed end-systolic stress, were more likely to suffer morbid events than those with initially normal values (P<.004). Cardiovascular events occurred in 29 of 100 patients (29%) and death in 10 of 100 patients (10%) among those who were in both the two highest quartiles of LV mass index and the two lowest quartiles of midwall shortening, as opposed to 21 of 194 (11%) and 4 of 194 (2.1%) of the remaining patients (odds ratio, 3.4; 95% CI, 1.8 to 6.3; P<.0001; and odds ratio, 5.3; 95% CI, 1.6 to 17.3; P<.006, respectively). In logistic analysis, increasing age, high LV mass, high systolic blood pressure, and low values for an interaction term between LV mass index and midwall shortening independently predicted cardiovascular events (.04<P<.001); increasing age, low midwall LV shortening as a percentage of predicted, and high value of the interaction term predicted the occurrence of cardiac death (.004<P<.0002). Survival analysis controlling for age confirmed that low midwall shortening independently predicted cardiac morbidity or death, especially in the subgroup of patients with LV hypertrophy. Conclusions Depressed midwall shortening is a predictor of adverse outcome in arterial hypertension; the combination of higher LV mass and lower midwall shortening identifies individuals at markedly increased risk.