Left Ventricular Contractility and Insulin Resistance in Essential Hypertension

The relationship between fasting insulin as well as the insulin response to an oral glucose tolerance test and echocardiographic cardiac geometry and function was assessed in 55 never-treated lean patients with essential hypertension and normal glucose tolerance and 31 age- and gender-matched normal subjects. The ratio of the area under the curve of the response of insulin and glucose to the oral glucose load was positively correlated with supine heart rate (r values of 0.37) or left ventricular contractility estimated by the end-systolic wall stress to end-systolic volume index ratio and the afterload-corrected fractional shortening (r = 0.59 and 0.36, respectively). No correlation between insulin and left ventricular mass index was observed. When hypertensive patients were divided into those without (n = 39) and with insulin resistance (n = 16), as defined by an elevated value of the ratio of the area under the curve of the response of insulin and glucose, it appeared that both heart rate, end-systolic wall stress to end-systolic volume index ratio and afterload-corrected fractional shortening were higher in patients with insulin resistance, whereas age, arterial pressure, left ventricular mass index, urinary electrolytes, and plasma renin activity were similar in the two groups. These results suggest that increased cardiac systolic performance and heart rate may be associated with insulin resistance in a subset of lean patients with never-treated essential hypertension.