Cardiomyopathies and Hypertension

Cardiomyopathies are diseases of the heart muscle. In the most common type, dilated cardiomyopathy, the heart muscle stretches, and the heart chamber becomes enlarged, or dilated. The heart can't pump normally, and heart failure often results. In hypertrophic cardiomyopathy, the heart muscle thickens abnormally, reducing the volume of the heart chambers and obstructing blood flow. Dangerous arrhythmias and sudden death may result. This type of cardiomyopathy is usually caused by a mutation in one of several genes.

• Cardiomyopathies affect 50,000 Americans and are a leading reason for heart transplants.

Hypertension

A person with hypertension has abnormally elevated blood pressure. The condition usually develops slowly and encompasses a whole spectrum of severity.

The control of blood pressure is complex, but salt regulation by the kidney is a key factor. High blood pressure is associated with increased salt levels, which cause increased plasma volume in the bloodstream. Thus, the basis of hypertension is an imbalance of salt and water regulation in the kidney, but its risks—coronary heart disease and stroke—are primarily in the circulatory system.

• 50 million Americans have hypertension.