Hypertrophic Cardiomyopathy (CMH) is a form of cardiomyopathy characterized by an abnormal and usually asymmetrical, thickening of the heart muscles. CMH is recognized as the most common cause of fatality in young athletes who die during heavy exercise. Myocardial disarray, or a disruption of the normal alignment of the cardiac muscles, is a prominent feature of the condition, along with disturbances in the electric functions of the heart. The most common symptoms of CMH include dyspnea due to increased stiffness of the left ventricle, angina, syncope, fatigue, light-headedness, palpitations, and arrhythmias, which in some patients cause heart failure, followed by sudden death. Although these symptoms are very similar to those of congestive heart failure, treatment strategy for both conditions are entirely different, and therefore, it is important to make a correct diagnosis.
Echocardiography with Doppler ultrasound, ECG, cardiac MRI, transesophageal echocardiogram, and heart monitors can help in the diagnosis of the condition. Treatment is aimed at easing the symptoms of dyspnea, syncope, and angina. Beta blockers or calcium channel blockers are regularly administered. Diuretics reduce the intravascular blood flow, decreasing the desired distension of the left ventricular outflow tract, and hence, need to be avoided. In severe cases, surgical intervention may be required. This may be in the form of septal myectomy, which involves removal of part of the thickened ventricular septum, septal ablation, involving destruction of the thickening by injection of alcohol, pacemaker installation, or implantation of a cardioverter-defibrillator. Prognosis of CMH varies greatly among patients from some patients leading a perfectly normal life, to some with a rapidly worsening course of the disease. Major risk factors for patients succumbing to a sudden heart failure include a young age at first diagnosis, family history of the condition, and the presence of specific mutations in relevant genes.
Studies have identified several loci associated with CMH. CMH1 is linked to mutations in the MYH7 (Myosin Heavy Chain 7, Cardiac muscle, Beta) gene.