Hypertrophic cardiomyopathy is a heart condition for which there is presently no cure. The severity of symptoms varies greatly among individuals, but in some cases the affliction can lead to death.
Screening high-risk patients is the best way to avert potential fatalities, says Dr. Michael S. Lee, the Associate Director of Interventional Cardiology Research and Assistant Clinical Professor of Medicine at UCLA Medical Center. “Hypertrophic cardiomyopathy is a complex disease that may have catastrophic consequences. Patients may have debilitating symptoms, which severely affect their quality of life,” says Lee. “Someone, especially young athletes, who may be viewed as a picture of health may suddenly die without any warning.”
Smart Business spoke with Lee about hypertrophic cardiomyopathy, how it is diagnosed and what treatment options are available.
What is hypertrophic cardiomyopathy?
Hypertrophic cardiomyopathy is a condition in which there is excessive thickening of the heart muscle or hypertrophy. The heart muscle may thicken in normal individuals due to hypertension or prolonged athletic training. However, in hypertrophic cardiomyopathy, muscle thickening occurs without an obvious cause. Microscopic examination of the heart muscle shows myocardial disarray or irregular, disorganized alignment of muscle cells.
How common is this condition?
Hypertrophic cardiomyopathy is a relatively common genetic cardiac disorder, which affects about one in 500 adults in the general population.
What causes hypertrophic cardiomyopathy?
The cause of hypertrophic cardiomyopathy is not fully known. Although the majority of cases are inherited, others have either no evidence of inheritance or there is insufficient information about the individual's family to assess inheritance. More than 400 genetic mutations have been identified in patients with hypertrophic cardiomyopathy, most of which are genes that encode contractile proteins of the cardiac sarcomere. The condition usually passes from one generation to the next in affected families, and generations are not skipped.
What are some common symptoms?
Hypertrophy more commonly develops in association with growth and is usually apparent by the late teens or early twenties. While some patients are asymptomatic, others may experience chest pain, shortness of breath, fatigue, palpitations, light-headedness, dizziness, and blackouts. Other complications include arrhythmias (like atrial fibrillation and ventricular tachycardia), and endocarditis (or infection of the heart).
However, the most devastating manifestation is sudden death, which may occur with little or no warning.
How is hypertrophic cardiomyopathy diagnosed?
Hypertrophic cardiomyopathy may be suspected because of symptoms, a murmur, or an abnormal electrocardiogram, but the diagnosis is made by an ultrasound scan of the heart called an echocardio-gram. Family screening of first-degree relatives will also identify children and adolescents with the condition.
What are the treatment options in patients with hypertrophic cardiomyopathy?
Although there is no cure, treatment options are available to improve symptoms and prevent complications. Medications like beta-blockers and calcium antagonists can reduce symptoms. Anti-arrhythmic drugs like amiodarone can be used to reduce the risk of sudden death. Patients should also take antibiotics before invasive procedures like teeth cleaning to prevent an infection of the heart valves called endocarditis.
If severe symptoms persist despite drug therapy, surgical myectomy (removal of muscle) can successfully relieve symptoms in patients whose left ventricular outflow tract is narrowed and causes obstruction of blood flow. Another option for patients with severe symptoms is non-surgical myectomy, in which a small amount of alcohol solution is injected into a minor branch of the coronary artery that supplies the upper septum, thus destroying this part of the heart muscle.
The best way to prevent sudden death is to screen and identify high-risk patients for sudden death and implant a defibrillator, a small device under the skin in the chest, which records and delivers an electrical shock when normal electrical action is absent. Patients may be advised not to participate in competitive sports or other strenuous physical effort.
DR. MICHAEL S. LEE is the Associate Director of Interventional Cardiology Research and Assistant Clinical Professor of Medicine at UCLA Medical Center. Reach him at (310) 825-8811.