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[Heart function (angioscintigraphic evaluation) and sympathetic tone in insulin-dependent diabetes mellitus]
S Ferraro1, M Santomauro, G Maddalena
1Istituto di Medicina Interna, Cardiologia e Cardiochirurgia, II Facoltà di Medicina e Chirurgia, Università di Napoli.
Insights
Diabetic patients with autonomic neuropathy show altered cardiac function, with higher peak ejection and filling rates compared to healthy individuals. This suggests early cardiac changes in type 1 diabetes, independent of traditional risk factors.
Area of Science:
- Cardiology
- Diabetology
- Autonomic Nervous System
Background:
- Cardiac failure is a significant cause of mortality in diabetic patients.
- The early onset and mechanisms of cardiac disease in diabetes, particularly in young individuals without macrovascular complications, remain unclear.
- Diabetic autonomic neuropathy may precede or coincide with cardiac dysfunction.
Purpose of the Study:
- To evaluate cardiac function and sympathetic tone in young type 1 diabetic patients with diabetic autonomic neuropathy.
- To compare cardiac parameters and sympathetic activity between diabetic patients and a control group of healthy subjects.
- To investigate potential early cardiac alterations in type 1 diabetes.
Main Methods:
- Study included 16 young type 1 diabetic patients (with autonomic neuropathy, no micro/macroangiopathy) and 10 healthy controls.
- Cardiac function assessed using radionuclide ventriculography (rest and exercise).
- Sympathetic tone evaluated via Ewing's clinical tests and plasma catecholamine levels.
Main Results:
- Diabetic patients and controls had comparable ejection fraction, cardiac output, and stroke volume at rest.
- The increase in ejection fraction during exercise was normal in most diabetics.
- Peak ejection and filling rates were significantly higher in diabetic patients (p < 0.001).
Conclusions:
- Young type 1 diabetic patients with autonomic neuropathy exhibit altered cardiac dynamics, characterized by increased peak ejection and filling rates.
- These findings suggest subclinical cardiac dysfunction in early type 1 diabetes, potentially linked to autonomic neuropathy.
- Cardiac function evaluation in diabetic patients should consider autonomic nervous system involvement.
Abstract:
Cardiac failure is a frequent feature in diabetic patients and it often causes their death. But how and when cardiac disease begins in this kind of patient is still debatable. For example, cardiac failure can be present even in the absence of atherosclerotic involvement of coronary arteries in young diabetics. The aims of our study were to evaluate the cardiac function and sympathetic tone of 16 young type 1 diabetic patients (8 M and 8 F, mean age: 27 years, SD +/- 5) in comparison with 10 normal subjects (4 M and 6 F, mean age: 30 years, SD +/- 7). Diabetic patients were choose from a large population because of the following features young age, absence of clinical and instrumental evidence of micro- or macroangiopathy, clinical evidence of diabetic autonomic neuropathy, proteinuria or arterial hypertension. They were in good metabolic control on daily insulin therapy of two or three administrations. Cardiac function was evaluated at rest and during submaximal exercise on a cycloergometer in supine position using radionuclide ventriculography with technetium 99m. Sympathetic tone was checked using the five clinical tests according to Ewing and the plasmatic level of catecholamines at rest was evaluated using high pressure chromatography. The ejection fraction, cardiac output, stroke volume of diabetics were comparable with those of normal subjects even in the presence of comparable systemic vascular resistance. The increase in ejection fraction during effort was normal. Only in one diabetic patient (incidentally the oldest one) did ejection fraction decrease (7%) during effort. The peak ejection and filling rates were significantly higher (p less than 0.001) in diabetic patients compared to those of normal subjects.(ABSTRACT TRUNCATED AT 250 WORDS)