What are the echocardiogram findings in Hypertrophic Cardiomyopathy (HCM)?

From the Guidelines

Echocardiography is the primary imaging modality for diagnosing and assessing hypertrophic cardiomyopathy (HCM), and key findings to look for include left ventricular wall thickness, asymmetric septal hypertrophy, systolic anterior motion of the mitral valve, left ventricular outflow tract obstruction, diastolic dysfunction, and left atrial enlargement. When evaluating HCM patients with echocardiography, it is essential to assess for the following:

• Left ventricular wall thickness ≥15 mm in adults or >2 standard deviations above the mean for age in children
• Asymmetric septal hypertrophy with a septal-to-posterior wall thickness ratio >1.3
• Systolic anterior motion of the mitral valve
• Left ventricular outflow tract obstruction (peak gradient ≥30 mmHg at rest or with provocation)
• Diastolic dysfunction
• Left atrial enlargement Additionally, assess for mitral regurgitation, right ventricular involvement, and apical hypertrophy, as these can impact disease severity and treatment decisions 1. Strain imaging can detect subclinical dysfunction, and a comprehensive echo evaluation helps determine disease severity, guide treatment, and assess risk stratification for sudden cardiac death 1. Regular follow-up echocardiograms are crucial for monitoring disease progression and treatment response in HCM patients, with repeat transthoracic echocardiogram (TTE) recommended every 1 to 2 years in asymptomatic patients and after changes in clinical status or events 1. In patients with HCM and resting peak LVOT gradient <50 mm Hg, a TTE with provocative maneuvers is recommended to uncover the presence of LVOTO, which may inform the care of the individual 1. Intraoperative transesophageal echocardiogram (TEE) is recommended for patients undergoing surgical septal myectomy, and TTE or intraoperative TEE with intracoronary ultrasound-enhancing contrast injection is recommended for patients undergoing alcohol septal ablation 1. Overall, echocardiography plays a vital role in the diagnosis, management, and follow-up of patients with HCM, and its findings should be used to guide treatment decisions and assess disease severity and risk stratification 1.

From the Research

Echocardiogram Findings in Hypertrophic Cardiomyopathy (HCM)

The diagnosis of HCM depends on several echocardiogram findings, including:

• Left ventricular wall thickness ≥15 mm 2
• Mitral valve systolic anterior motion
• Anteriorly positioned mitral valve leaflet coaptation
• Anomalous anterior insertion of papillary muscles
• Diastolic dysfunction

Left Ventricular Outflow Tract (LVOT) Gradient

• Resting LVOT gradient occurs in 25% of patients 2
• Provocable gradients may be demonstrated in more than half of patients 2
• High LVOT gradients (≥ 50 mm Hg) are an indication for pharmacotherapy 3

Risk Assessment and Treatment Guidance

• Echocardiography is important for sudden death risk assessment 2
• Patients with a wall thickness more than 30 mm have a higher risk of sudden cardiac death 2
• Echocardiography guides the treatment of HCM, including medical treatment and invasive procedures such as surgical septal myectomy and alcohol septal ablation 2, 4

Echocardiogram Findings for Treatment Evaluation

• Echocardiography is used to evaluate the results of treatment, including the reduction of LVOT gradient and improvement of symptoms 2, 3
• Intraoperative transesophageal echocardiography is used to evaluate surgical results and guide immediate revision if necessary 2