Radionuclide assessment of left ventricular diastolic filling in diabetes mellitus with and without cardiac autonomic neuropathy

Abstract

Indexes of left ventricular diastolic filling were measured by radionuclide ventriculography in 28 patients with insulin-dependent diabetes mellitus without evidence of ischemic heart disease. Six patients (21%) had abnormal diastolic filling and differed from diabetic patients with normal filling in their greater severity of cardiac autonomic neuropathy, assessed by noninvasive means, and their lower plasma norepinephrine levels in the supine (131.1 +/- 24.7 versus 356.2 +/- 58.4 pg/ml, p less than 0.01) and upright (224.9 +/- 47.8 versus 673.3 +/- 122.3 pg/ml, p less than 0.005) positions. The diabetic patients determined as having cardiac autonomic neuropathy (n = 15) had depressed left ventricular diastolic filling compared with subjects free of autonomic neuropathy, whether measured as the time to peak filling rate (154.2 +/- 12.0 versus 119.1 +/- 10.6 ms, p less than 0.05) or the time to peak filling rate normalized to the cardiac cycle length (24.3 +/- 2.2 versus 16.2 +/- 1.5%, p less than 0.01). Of the various tests of autonomic nervous system function, the strongest correlate of impaired diastolic filling was orthostasis, measured as the decrease in systolic blood pressure with standing (r = 0.584, p less than 0.001). Thus, in patients with diabetes mellitus, alterations in sympathetic nervous system activity are associated with abnormalities of left ventricular diastolic filling.