From the Guidelines
To diagnose hypertrophic cardiomyopathy (HCM) on echocardiogram, look for left ventricular wall thickness ≥15 mm in adults or >2 standard deviations above the mean for age in children, asymmetric septal hypertrophy, systolic anterior motion of the mitral valve, left ventricular outflow tract obstruction, diastolic dysfunction, and left atrial enlargement, as recommended by the 2024 AHA/ACC/AMSSM/HRS/PACES/SCMR guideline 1.
Key Echocardiogram Findings
- Left ventricular wall thickness ≥15 mm in adults or >2 standard deviations above the mean for age in children
- Asymmetric septal hypertrophy (septum/posterior wall ratio >1.3)
- Systolic anterior motion of the mitral valve
- Left ventricular outflow tract obstruction (peak gradient >30 mmHg at rest or >50 mmHg with provocation)
- Diastolic dysfunction
- Left atrial enlargement
Additional Measurements to Consider
- Mitral regurgitation severity
- Right ventricular involvement
- Apical hypertrophy variant
Recommended Imaging Modalities
- Comprehensive 2D echocardiography has a primary role in establishing the diagnosis of HCM, determining hypertrophy pattern, presence of LV apical aneurysms, LV systolic and diastolic function, mitral valve function, and presence and severity of LVOTO, as stated in the 2024 AHA/ACC/AMSSM/HRS/PACES/SCMR guideline 1.
- Transthoracic echocardiogram (TTE) is recommended in the initial evaluation of patients with suspected HCM, and repeat TTE is recommended every 1 to 2 years to assess the degree of myocardial hypertrophy, dynamic LVOTO, MR, and myocardial function 1.
- Intraoperative transesophageal echocardiogram (TEE) is recommended to assess mitral valve anatomy and function and adequacy of septal myectomy in patients undergoing surgical septal myectomy 1.
- TTE or intraoperative TEE with intracoronary ultrasound-enhancing contrast injection of the candidate’s septal perforator(s) is recommended for patients undergoing alcohol septal ablation 1.
From the Research
Echocardiogram Findings in Hypertrophic Cardiomyopathy (HCM)
The echocardiogram findings in HCM include:
- Left ventricular wall thickness ≥15 mm 2
- Mitral valve systolic anterior motion, anteriorly positioned mitral valve leaflet coaptation, anomalous anterior insertion of papillary muscles, and diastolic dysfunction 2
- Resting left ventricular outflow tract (LVOT) gradient occurs in 25% of patients and provocable gradients may be demonstrated in more than half of patients 2
- Patients with a wall thickness more than 30 mm have a higher risk of sudden cardiac death, as often as 2%/year 2
Diagnostic Evaluation
Diagnostic evaluation of HCM includes:
- History-taking and physical examination
- Genetic studies
- Transthoracic echocardiography
- Cardiac MRI 3
Treatment Guidance
Echocardiography is important for guiding treatment in HCM, including:
- Medical treatment with beta-blockers, disopyramide, verapamil 2
- Invasive treatment such as surgical septal myectomy, alcohol septal ablation, or DDD pacemaker 2
- Preoperative TTE is a necessary guide for the surgeon in planning the operation 2
- Intraoperative transesophageal echocardiography is a very important tool for evaluating surgical results 2