Hypertrophic cardiomyopathy is a genetic disorder characterized by the thickening of the left ventricle in the absence of a secondary cause. Once thought to be a rare disease, it’s now estimated that hypertrophic cardiomyopathy occurs in 1 out of every 200 individuals.
Since the underlying genetic cause of this disease was first discovered in the 1990s, there have been major advances in the diagnosis and treatment of hypertrophic cardiomyopathy.
Hypertrophic cardiomyopathy is largely underdiagnosed because people living with the condition are often without symptoms. Those who do have symptoms can present with palpitations, shortness of breath, chest pain, dizziness or syncope. Many patients are diagnosed incidentally after an abnormal ECG or echocardiogram. However, many patients remain undiagnosed or misdiagnosed. Advanced cardiac imaging with echocardiography with strain imaging and cardiac MRI are often necessary to confirm the diagnosis.
A subset of individuals with hypertrophic cardiomyopathy will have left ventricular outflow tract obstruction, causing symptoms including chest pain, shortness of breath, dizziness or syncope. The obstruction can be improved with lifestyle modification and medication.
For severe obstruction with symptoms refractory to medical therapy, alcohol septal ablation and cardiac surgery can be utilized to reduce the size of the interventricular septum and the obstruction. Additionally, some patients with hypertrophic cardiomyopathy have intrinsic mitral valve disease that requires complex surgical mitral valve repair.
People living with hypertrophic cardiomyopathy can live a normal lifespan. However, it is imperative that patients be risk stratified for ventricular arrhythmias that can cause sudden death. For those who are at risk for sudden death, implantable cardiac defibrillators can provide a lifesaving shock to terminate a deadly rhythm within seconds.
Shared decision-making regarding the risk of competitive athletics is an important consideration for lifestyle, especially in children and young adults.
Hypertrophic cardiomyopathy is caused by mutations in proteins that form the cardiac sarcomere, the contractile apparatus of the cardiac myocyte, which is the muscle cell of the heart. Mutations in eight sarcomeric proteins are assessed with genetic testing. We also routinely test for phenocopies, diseases of the heart that can mimic hypertrophic cardiomyopathy but have a different underlying cause and thus different treatment. However, the known sarcomeric mutations were derived from genetic datasets with limited population diversity. As a result, less than half of patients with hypertrophic cardiomyopathy have an identifiable mutation.
Identifying the underlying mutation can be useful for cascade genetic testing of family members to identify those at risk of developing hypertrophic cardiomyopathy. For those who choose to not undergo genetic testing or in whom genetic testing is inconclusive, family members can be screened by echocardiography.
The understanding of the pathophysiology of hypertrophic cardiomyopathy has led to the development of novel therapeutics. Myosin inhibitors act directly on the sarcomere to reduce hypercontractility and relieve left ventricular outflow obstruction. Mavacamten (Camzyos) is currently the only FDA-approved myosin inhibitor, but other drugs are currently under investigation for obstructive hypertrophic cardiomyopathy and diastolic heart failure. The future of hypertrophic cardiomyopathy care is hopeful, and Wellstar plans to lead the region in increasing access to new treatments for diverse patient populations.
Dr. Burroughs is a cardiovascular disease specialist with Wellstar Center for Cardiovascular Care. She received her medical degree from Harvard Medical School and is certified in cardiovascular care by the American Board of Internal Medicine. She treats patients in Marietta and Hiram.