Hypertrophic cardiomyopathy: Dr. Steve Ommen, a cardiologist at the Mayo Clinic, discusses hypertrophic cardiomyopathy. Hypertrophic cardiomyopathy is an inherited disease that causes an abnormally thick heart muscle. This can cause symptoms such as shortness of breath, chest pressure or lightheadedness, or even passing out. Some are at risk for sudden cardiac death from arrhythmia, and will need an ICD-defibrillator.