Pirfenidone to Treat Hypertrophic Cardiomyopathy

This study will examine the effectiveness of the drug pirfenidone (Deskar) in improving heart function in patients with hypertrophic cardiomyopathy (HCM). Stiffening of the heart muscle in patients with HCM impairs the heart's ability to relax and thus fill and empty properly. This can lead to heart failure, breathlessness and excessive fatigue. The heart's inability to relax may be due to scarring, or fibrosis, in the muscle wall. This study will test whether pirfenidone can reduce fibrosis, improve heart relaxation and reduce abnormal heart rhythms. Men and women 20 to 75 years old with HCM may be eligible for this study. Participants will undergo a physical examination, blood tests, and other tests and procedures, described below, to assess heart function. When the tests are completed, patients will be randomly assigned to one of two treatment groups. One group will take a pirfenidone capsule and the other will take a placebo (a look-alike pill with no active ingredient) twice a day with meals for 6 months. For the pirfenidone group, the dose of drug will be increased gradually from 400 to 800 milligrams. At the end of 6 months, all patients will repeat the physical examination and heart tests that were done before starting medication. These include: * Electrocardiogram (ECG) - electrodes are attached to the heart to record the heart's electrical activity, providing information on the heartbeat. * Echocardiogram - a probe held against the chest wall uses sound waves to produce images of the heart, providing information on the function of the heart chambers. * 24-hour Holter monitor - a 24-hour recording of the electrical activity of the heart monitors for abnormal heartbeats or conduction abnormalities. * Magnetic resonance imaging (MRI) - Radiowaves and a strong magnetic field are used to produce images of the heart, providing information on the thickness and movement of the heart muscle. * Radionuclide angiogram - a radioactive tracer is injected into a vein