Myocardial contractility and left ventricular function in obese patients with essential hypertension

Although the risk of developing congestive heart failure increases in parallel with the degree of obesity, load-dependent indexes of left ventricular function are found to be reduced in patients with morbid obesity only. We used the ratio of end-systolic wall stress to end-systolic volume index, which is load-independent, to assess myocardial contractility in 23 nonobese, 28 mildly obese and 26 moderately obese patients with mild to moderate essential hypertension. Although load-dependent indexes (i.e., ejection fraction, fractional fiber shortening and velocity of circumferential fiber shortening) were similar in the 3 groups, end-systolic wall stress to end-systolic volume index was lower in the moderately obese group (2.63 +/- 0.4, p less than 0.002) and even in the mildly obese group (2.88 +/- 0.8, p less than 0.05) than in the nonobese group (3.27 +/- 0.7). Further, there was a significant inverse relation between end-systolic wall stress to end-systolic volume index and body mass index (r = -0.34, p less than 0.005), diastolic diameter (r = -0.56, p less than 0.001) and left ventricular mass index (r = -0.55, p less than 0.001). Some obese patients have depressed myocardial contractility when compared with lean patients despite well-preserved pump function.