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Diabetes mellitus and cardiac function
M A Mahgoub1, A S Abd-Elfattah
1Department of Surgery, Medical College of Virginia, Virginia Commonwealth University, Richmond, USA.
Insights
Diabetic patients face high cardiovascular risks, including atherosclerosis and heart failure. Careful treatment considering metabolic changes is crucial for managing these serious complications.
Area of Science:
- Cardiology
- Endocrinology
- Pharmacology
Background:
- Cardiovascular complications are the leading cause of death in diabetic patients.
- Diabetes mellitus exacerbates coronary atherosclerosis, myocardial infarction, heart failure, and left ventricular hypertrophy.
- Diabetic cardiomyopathy involves diastolic and systolic dysfunction, with altered intracellular ion concentrations.
Purpose of the Study:
- To review the cardiovascular complications in diabetic patients.
- To discuss the challenges and considerations in treating cardiovascular issues in diabetes.
- To examine the effects of specific pharmacological agents on the diabetic heart.
Main Methods:
- Literature review of cardiovascular complications in diabetes.
- Analysis of ionic and metabolic changes in diabetic cardiomyopathy.
- Evaluation of drug classes like ACE inhibitors, calcium channel blockers, and potassium channel modulators.
Main Results:
- Diabetes accelerates atherosclerosis and increases risks of myocardial infarction, re-infarction, and heart failure.
- Diabetic cardiomyopathy exhibits early diastolic and later systolic dysfunction with ion imbalances.
- Potassium channel openers and blockers have complex, sometimes contradictory, effects in animal models and humans regarding preconditioning, infarct size, insulin release, and arrhythmias.
Conclusions:
- Cardiovascular treatment in diabetics requires caution due to unique ionic and metabolic alterations.
- Understanding the nuanced effects of drugs like potassium channel modulators is vital for effective management.
- Diabetic autonomic neuropathy, particularly parasympathetic dysfunction, contributes to silent ischemia and increased cardiovascular risk.
Abstract:
Cardiovascular complications are the most common causes of morbidity and mortality in diabetic patients. Coronary atherosclerosis is enhanced in diabetics, whereas myocardial infarction represents 20% of deaths of diabetic subjects. Furthermore, re-infarction and heart failure are more common in the diabetics. Diabetic cardiomyopathy is characterized by an early diastolic dysfunction and a later systolic one, with intracellular retention of calcium and sodium and loss of potassium. In addition, diabetes mellitus accelerates the development of left ventricular hypertrophy in hypertensive patients and increases cardiovascular mortality and morbidity. Treating the cardiovascular problems in diabetics must be undertaken with caution. Special consideration must be given with respect to the ionic and metabolic changes associated with diabetes. For example, although ACE inhibitors and calcium channel blockers are suitable agents, potassium channel openers cause myocardial preconditioning and decrease the infarct size in animal models, but they inhibit the insulin release after glucose administration in healthy subjects. Furthermore, potassium channel blockers abolish myocardial preconditioning and increase infarct size in animal models, but they protect the heart from the fatal arrhythmias induced by ischemia and reperfusion which may be important in diabetes. For example, diabetic peripheral neuropathy usually presents with silent ischemia and infarction. Mechanistically, parasympathetic cardiac nerve dysfunction, expressed as increased resting heart rate and decreased respiratory variation in heart rate, is more frequent than the sympathetic cardiac nerve dysfunction expressed as a decrease in the heart rate rise during standing.