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Cardiac function and coronary arteriography in asymptomatic type 1 (insulin-dependent) diabetic patients: evidence
Insights
Diabetic heart disease may exist in asymptomatic patients. Type 1 diabetes patients showed impaired cardiac function during exercise, with histological changes suggesting diabetic microangiopathy, not coronary artery disease.
Area of Science:
- Cardiology
- Diabetology
- Pathology
Background:
- Type 1 diabetes (insulin-dependent) is a chronic condition affecting multiple organs.
- Cardiac complications in diabetic patients are well-documented but often associated with coronary artery disease.
- The existence of a specific diabetic heart disease independent of coronary issues requires further investigation.
Purpose of the Study:
- To investigate cardiac function in asymptomatic Type 1 diabetic patients.
- To determine if a specific diabetic heart disease exists.
- To compare cardiac responses to physiological stress in diabetic and non-diabetic individuals.
Main Methods:
- Studied 63 asymptomatic Type 1 diabetic patients (30-50 years) and 45 controls.
- Utilized radionuclide ventriculography and exercise electrocardiography at rest and during isometric, cold-pressor, and dynamic exercise.
- Performed cardiac catheterization, coronary arteriography, and endomyocardial biopsy in a subset of patients.
Main Results:
- Diabetic patients and controls showed similar resting left ventricular ejection fractions and responses to isometric/cold-pressor tests.
- Male diabetic patients exhibited a smaller increase in left ventricular ejection fraction during dynamic exercise (9% vs 14%).
- Histological findings in diabetic patients included arteriolar thickening and interstitial fibrosis, indicative of diabetic microangiopathy.
Conclusions:
- Cardiac function can be abnormal in Type 1 diabetic patients without evidence of coronary heart disease.
- Abnormal cardiac responses during dynamic exercise suggest a potential diabetic cardiomyopathy.
- Histological changes support the presence of diabetic microangiopathy affecting the heart.
Abstract:
Cardiac function was examined in 63 asymptomatic Type 1 (insulin-dependent) diabetic patients, aged 30-50 years, using radionuclide ventriculography and exercise electrocardiography to investigate the possible existence of a specific diabetic heart disease. Comparisons were made with 45 age- and sex-matched non-diabetic controls. Radionuclide ventriculography was performed at rest and during the physiological stresses of isometric exercise, cold-pressor testing and dynamic exercise. Scans were technically satisfactory in 56 of the diabetic patients and 38 of the control subjects. The resting left ventricular ejection fractions and the responses to isometric exercise and cold-pressor testing were similar in the diabetic patients and controls. A smaller rise in the left ventricular ejection fraction during dynamic exercise was observed in male diabetic patients compared with male control subjects (9 +/- 1% (mean +/- SEM) vs 14 +/- 1% (p less than 0.005)). A similar trend was observed in female diabetic patients, with a rise of 5 +/- 1% on dynamic exercise compared with a rise of 8 +/- 1% in the control group. Sixteen diabetic patients (29%) demonstrated an abnormal response to dynamic exercise, and 5 of these had an abnormal exercise electrocardiogram. Cardiac catheterisation and coronary arteriography were performed in eight of these 16 patients, and all 8 had normal coronary arteries. Endomyocardial biopsy revealed arteriolar thickening and interstitial fibrosis in 5 patients, and in 2 patients basement membrane thickening was conspicuous. Thus, in diabetic patients cardiac function may be abnormal without evidence of coronary heart disease, and some patients appear to have the histological changes consistent with a diabetic microangiopathy involving the heart.