From the Guidelines
Genetic testing is a crucial component in the diagnosis and management of Hypertrophic Obstructive Cardiomyopathy (HOCM), as it confirms diagnosis, guides family screening, and informs treatment decisions. The test typically involves analyzing genes associated with sarcomere proteins, particularly MYH7, MYBPC3, TNNT2, and TNNI3, which account for approximately 60-70% of genetic causes of HOCM 1.
Key Points
- Genetic testing has several clinical benefits, including confirmation of the diagnosis, preclinical diagnosis, cascade genetic testing in the family, and guiding reproductive decisions 1.
- Cascade genetic testing should be offered to first-degree relatives when a pathogenic variant is identified in a patient, allowing for early identification of at-risk family members before clinical manifestations appear 1.
- Genetic counseling is essential both before and after testing to discuss implications, limitations, and psychological impact 1.
- The testing process involves analyzing genes associated with sarcomere proteins, and genetic information can help predict disease progression, risk stratification for sudden cardiac death, and response to medications like beta-blockers or calcium channel blockers 1.
Recommendations
- Genetic testing is recommended for patients with clinical features of HOCM to confirm diagnosis, guide family screening, and inform treatment decisions 1.
- Cascade genetic testing should be offered to first-degree relatives when a pathogenic variant is identified in a patient 1.
- Genetic counseling is essential both before and after testing to discuss implications, limitations, and psychological impact 1.
From the Research
Role of Genetic Testing in HOCM
- Genetic testing has become more accessible and is increasingly being incorporated into the care of patients with hypertrophic cardiomyopathy, including HOCM 2.
- Genetic test results can help to refine diagnosis and distinguish at-risk relatives from those who are not at risk 2.
Diagnosis and Management of HOCM
- HOCM is diagnosed based on the presence of a left ventricular outflow tract (LVOT) gradient at rest or during provocation, as well as left ventricular wall thickness ≥15 mm 3, 4, 5.
- Management of HOCM encompasses activity restriction, prevention of sudden cardiac death, control of symptoms, and screening of relatives 3.
- Pharmacologic treatment of symptoms in patients with HOCM consists of negative inotropic drugs, such as beta blockers, disopyramide, and nondihydropyridine calcium channel blockers 3, 4, 6.
- For patients with intolerable symptoms despite optimal conservative therapy, septal reduction therapy (SRT) should be considered, including septal myectomy or alcohol septal ablation (ASA) 3, 4, 6, 5.
Importance of Echocardiography in HOCM
- Echocardiography is the best technique to diagnose, evaluate, follow-up, and guide the treatment of HOCM 4.
- Echocardiography is important for sudden death risk assessment, with patients having a wall thickness more than 30 mm at higher risk of sudden cardiac death 4.
- Echocardiography is also used to guide invasive treatment, such as surgical septal myectomy or ASA, and to evaluate surgical results 4.