Diabetic Heart Disease

Georgetown University School of Nursing & Health Studies Left ventricular hypertrophy Myocardial lipotoxicity Interstitial collagen deposits Diastolic dysfunction

Despite advances in the detection and treatment of cardiovascular disorders, about one in four deaths in America is caused by heart disease annually. But heart disease is only one of many chronic medical conditions adults experience. The American Heart Association cites heart disease as the cause of death in “at least 68 percent of people age 65 or older,” and there is an established link between cardiovascular disease and diabetes that suggests heart health has implications beyond the circulatory system. Click on a + to see how diabetes contributes to cardiac dysfunction.

Left ventricular hypertrophy

A potential indicator of type 2 diabetes, hyperinsulinemia is a condition, often a result of insulin resistance, that involves excessive levels of insulin in the blood regardless of glucose levels. Hyperinsulinemia can thicken the heart’s left ventricular wall over time. As a result, the overdeveloped muscle becomes less efficient at pumping oxygenated blood to the body’s tissues and organs.

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Myocardial lipotoxicity

Both type 1 and type 2 diabetes may cause fatty acid deposits to accumulate within the myocardium — the heart’s muscle fibers. These deposits in turn can impair cell signaling and even cause myocardial cells to die.

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Interstitial collagen deposits

Diabetes can promote excessive amounts of collagen to build up around cardiac blood vessels and within the heart muscle itself. These fibrous deposits cause the tissue to become rigid and stiff, making it difficult for the heart to contract forcefully since it no longer has the elastic stretch it needs to expand and then retighten.

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Diastolic dysfunction

In a normal heart, the ventricles relax and fill with blood during diastole, which is the “quiet period” of the heartbeat cycle. However, in some people with diabetes, the ventricles never fully relax — a condition called diastolic dysfunction— which reduces the capacity of the ventricles’ reservoir to refill with blood. This means that when the heart goes into systole, or  “the active period,” there isn’t enough blood pumped out of the heart and into the body, resulting in reduced circulation and, eventually, pulmonary congestion, wherein fluid accumulates in the lungs and limits or prevents gas exchange.

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