Impaired left-ventricular function in insulin-dependent diabetic patients with increased urinary albumin excretion

Abstract

Cardiac function was studied in 30 patients with insulin-dependent diabetes mellitus. Three groups, matched for age and diabetes duration, were defined as: group I (n=10), normal urinary albumin excretion <30 mg 24 h^-1; group II (n=10), incipient diabetic nephropathy (urinary albumin excretion in the range of 30-300 mg 24 h^-1); and group III (n=10), clinical diabetic nephropathy (urinary albumin excretion >300 mg 24 h^-1). Ten non-diabetic subjects matched for sex and age served as controls. The left-ventricular end-diastolic volume measured by radionuclide cardiography was, at rest and during exercise, lower in group II and III compared with controls (p<0.05), while intermediate values were found in group I. The cardiac output was similar in the control group and group I; it was reduced, but not significantly so (p=0.10), in group III and was significantly lower in group II (p<0.05). Stroke volume was also lower in group II and III than in controls (p<0.05), but not so in group I. These differences could not be explained by differences in metabolic control, blood pressure, blood volume status, degree of autonomic neuropathy or frequency of coronary heart disease. Our results might suggest that insulin-dependent diabetic patients with slightly but persistently elevated urinary albumin excretion have reduced diastolic compliance of the left-ventricle leading to impaired cardiac performance. It can be hypothesized that the impaired cardiac function is of pathophysiological importance for the decreased aerobic work capacity previously described in these patients, but it remains to be clarified to what extent it is responsible for their high cardiovascular mortality.

Key Words:

• Key-words
• insulin-dependent diabetes mellitus
• left-ventricular end-diastolic volume
• radionuclide cardiography
• urinary albumin excretion