Diagnostic Screening for Hypertrophic Cardiomyopathy (HCM)

Primary Diagnostic Tools

The American College of Cardiology recommends transthoracic echocardiography (TTE) as the cornerstone diagnostic test in the initial evaluation of all patients with suspected HCM, allowing assessment of myocardial hypertrophy, dynamic obstruction, and myocardial function 1, 2, 3
A 12-lead ECG is recommended as part of the initial evaluation of all patients with suspected HCM, with abnormalities present in 75-95% of patients 2, 5
Twenty-four-hour ambulatory (Holter) electrocardiographic monitoring is recommended in the initial evaluation to detect ventricular tachycardia and identify candidates for ICD therapy 2, 5

The European Society of Cardiology defines HCM in adults by a wall thickness ≥15 mm in one or more LV myocardial segments that is not explained solely by loading conditions 6
In first-degree relatives of patients with unequivocal disease, a wall thickness ≥13 mm is considered diagnostic 6
In children, the diagnosis requires an LV wall thickness more than two standard deviations greater than the predicted mean (z-score >2) 6

The American College of Cardiology recommends TTE as a component of the screening algorithm for family members of patients with HCM unless the family member is genotype negative in a family with known definitive mutations 2, 3
A 12-lead ECG should accompany echocardiography in the screening of family members 2, 5
For children of HCM patients, periodic (12-18 months) TTE screening is recommended starting by age 12 years or earlier if a growth spurt or signs of puberty are evident 3

For genotype-positive individuals who do not express the HCM phenotype, serial ECG, TTE, and clinical assessment should be performed every 12-18 months in children/adolescents and approximately every 5 years in adults 1, 2
For family members with unknown genetic status, follow-up screening intervals should be based on age, with optional screening under 12 years, every 12-18 months from 12-18/21 years, and at least every 5 years over 18/21 years 2, 5

Exercise TTE can be useful in detecting and quantifying dynamic LVOT obstruction in patients without resting obstruction 3

Ongoing clinical screening is not indicated in genotype-negative relatives in families with known HCM mutations 1