What are the key echo findings and management strategies for patients with Hypertrophic Cardiomyopathy (HCM)?

Key Echocardiographic Findings in Hypertrophic Cardiomyopathy (HCM)

Transthoracic echocardiography (TTE) is the primary imaging modality for diagnosis, risk stratification, and management of patients with hypertrophic cardiomyopathy. 1

Diagnostic Findings

• Left ventricular hypertrophy pattern: Measurement of maximum diastolic wall thickness using 2D short-axis views in all LV segments from base to apex is essential to characterize the extent and distribution of hypertrophy 1
• Asymmetric septal hypertrophy: Most common pattern, but various patterns exist including concentric, apical, and mid-ventricular 1
• Left ventricular outflow tract obstruction (LVOTO): Defined as peak gradient ≥30 mmHg at rest or ≥50 mmHg with provocation 1
• Systolic anterior motion (SAM) of mitral valve: Contributing to LVOTO and often associated with mitral regurgitation 1
• Left atrial enlargement: Reflects chronic diastolic dysfunction and is associated with risk of atrial fibrillation 1, 2
• Diastolic dysfunction: Assessed through pulsed Doppler of mitral valve inflow, tissue Doppler velocities at mitral annulus, pulmonary vein flow velocities, and pulmonary artery pressure 1

Dynamic Assessment

• Provocative maneuvers: Essential when resting LVOT gradient is <50 mmHg, including:

  • Valsalva maneuver in sitting and semi-supine positions 1, 2
  • Standing from squatting position 1
  • Exercise echocardiography for symptomatic patients to detect provocable LVOTO 1

• Exercise echocardiography: Recommended for symptomatic patients without significant resting or provoked gradient to detect exercise-induced LVOTO and mitral regurgitation 1

Advanced Echocardiographic Techniques

• Contrast echocardiography: Useful when apical hypertrophy, apical aneurysm, or atypical patterns are suspected but not clearly visualized 1
• Transesophageal echocardiography (TEE): Indicated when:
  • TTE is inconclusive for clinical decision-making 1
  • Planning for septal myectomy to assess mitral valve anatomy 1
  • During septal reduction procedures to guide intervention 1
• Strain imaging: Often shows reduced longitudinal deformation despite normal ejection fraction, particularly at sites of hypertrophy 1

Findings Suggesting Specific Etiologies

• Concentric hypertrophy: More common in metabolic and infiltrative disorders 1
• Biventricular hypertrophy: Common in Noonan syndrome and related disorders 1
• Sparkling or granular myocardial texture: Suggests amyloidosis 1
• Increased interatrial septum thickness: Characteristic of amyloidosis 1
• Increased AV valve thickness: Seen in amyloidosis and Anderson-Fabry disease 1
• Global LV hypokinesia: May indicate advanced sarcomeric HCM or specific metabolic disorders 1

Management Applications

• Serial monitoring: Recommended every 1-2 years in stable patients to assess changes in hypertrophy, obstruction, and ventricular function 1

• Septal reduction therapy guidance:

  • Perioperative TEE for surgical myectomy to guide resection and assess complications 1
  • Intracoronary contrast injection during alcohol septal ablation to ensure correct localization 1
  • Post-procedure assessment within 3-6 months to evaluate results 1

• Family screening: TTE recommended for first-degree relatives and periodic follow-up (1-2 years in children/adolescents, 3-5 years in adults) for genotype-positive individuals 1

Common Pitfalls to Avoid

• Missing dynamic obstruction: Always perform provocative maneuvers when resting gradient is <50 mmHg 1, 2
• Overlooking apical variants: Use contrast echocardiography when apical segments are poorly visualized 1
• Inadequate assessment of mitral valve apparatus: Critical for understanding mechanism of obstruction and planning interventions 1
• Relying solely on ejection fraction: EF is often normal or hyperdynamic despite impaired myocardial function 1
• Incomplete wall thickness assessment: Measure all segments from base to apex to avoid missing localized hypertrophy 1