Diagnosis and Management of Hypertrophic Cardiomyopathy

Clinical Presentation and Diagnosis

• The American College of Cardiology recommends that a murmur with maximal intensity at the 4th left intercostal space should be considered hypertrophic cardiomyopathy (HCM) until proven otherwise, and requires echocardiography to rule out this potentially life-threatening condition 1, 2, 3, 4
• The American College of Cardiology states that the 4th left intercostal space is a critical landmark that distinguishes HCM from other causes of left ventricular outflow tract obstruction, with HCM typically having a maximal thrill and murmur at this location 1, 2, 3, 4
• The American Heart Association notes that valvular aortic stenosis typically has a maximal murmur at the 2nd right intercostal space 1, 2, 3, 4
• The American College of Cardiology recommends that dynamic auscultation, including the Valsalva maneuver, standing, and squatting, is essential for diagnosing HCM, as the murmur typically increases with Valsalva or standing, and softens or disappears with squatting 1, 2, 5, 6

Diagnostic Criteria

• The American College of Cardiology states that echocardiography is required for any murmur at the 4th left intercostal space if the murmur is grade 3 or louder, or if any symptoms are present, such as syncope, angina, heart failure, or family history of sudden cardiac death 1, 2, 4, 7
• The American Heart Association recommends that echocardiography is also required if there are abnormal dynamic auscultation findings, abnormal ECG or chest X-ray, or abnormal physical findings, such as S4, paradoxical splitting, or abnormal carotid pulse 7

Treatment and Management

• The American College of Cardiology recommends that treatment for HCM depends entirely on the underlying diagnosis confirmed by echocardiography, and may include avoiding dehydration and vasodilators, using beta-blockers or calcium channel blockers for symptomatic relief, and considering implantable cardioverter-defibrillator (ICD) therapy for high-risk patients 4, 5
• The American Heart Association states that septal reduction therapy, such as surgical myectomy or alcohol septal ablation, may be considered for severe symptomatic obstruction refractory to medical therapy 4
• The American College of Cardiology recommends that activity restriction from competitive athletics is recommended for patients with HCM 1