What is the diagnostic approach for Left Ventricular Hypertrophy (LVH)?

Diagnostic Approach to Left Ventricular Hypertrophy (LVH)

The diagnosis of LVH requires a multimodality approach with echocardiography as the cornerstone diagnostic test, supplemented by electrocardiography and, when necessary, cardiac magnetic resonance imaging (CMR). 1

Primary Diagnostic Tests

Echocardiography

• First-line imaging modality for LVH diagnosis 1, 2
• Diagnostic criteria:
  • LV wall thickness ≥15 mm in one or more myocardial segments in adults
  • For first-degree relatives of patients with HCM: LV wall thickness ≥13 mm
  • For children: LV wall thickness >2 standard deviations above predicted mean (z-score >2) 1
• Comprehensive assessment should include:
  • Maximum LV wall thickness measurement
  • Distribution pattern of hypertrophy
  • Assessment of LV outflow tract obstruction
  • Mitral valve function evaluation
  • Left atrial size measurement
  • LV systolic and diastolic function 1, 2

12-Lead Electrocardiography

• Recommended for all patients with suspected LVH 1
• Common ECG findings in LVH:
  • Increased QRS voltage
  • ST-T wave abnormalities
  • Left axis deviation
  • Left atrial abnormality
  • QRS prolongation 1
• ECG is abnormal in 75-95% of patients with HCM but has lower sensitivity than imaging 1
• Common ECG criteria include:
  • Cornell voltage criteria
  • Sokolow-Lyon index
  • Cornell voltage product 3

Advanced Imaging

Cardiovascular Magnetic Resonance (CMR)

• Indicated when:
  • Echocardiography is inconclusive or technically limited
  • Suspected apical hypertrophy
  • Need for precise assessment of LV wall thickness and mass
  • Assessment of myocardial fibrosis/scarring 1, 2
• CMR advantages:
  • Superior spatial resolution
  • Sharp contrast between blood and myocardium
  • Tomographic imaging of entire LV myocardium
  • Late gadolinium enhancement (LGE) to detect myocardial fibrosis 1
• In one study, 6% of patients with suspected HCM were identified with increased LV wall thickness by CMR but not by echocardiography 1

Diagnostic Algorithm

1. Initial Assessment:

   • 12-lead ECG to detect voltage criteria and associated abnormalities
   • Comprehensive transthoracic echocardiography

2. If Echocardiography is Diagnostic:

   • LV wall thickness ≥15 mm (adults) or z-score >2 (children)
   • Proceed with risk stratification and management

3. If Echocardiography is Inconclusive:

   • Proceed to CMR imaging for:
     • Better visualization of areas not well seen on echo (anterolateral wall, apex)
     • More precise measurement of wall thickness
     • Assessment of myocardial fibrosis 1

4. Additional Testing:

   • 24-hour ambulatory ECG monitoring to detect arrhythmias 1, 2
   • Exercise echocardiography to assess for provocable obstruction 1, 2
   • Consider genetic testing if HCM is confirmed 1, 2

Special Considerations

ECG Limitations

• ECG has lower sensitivity (6-50%) compared to imaging (85-100%) 4
• Sensitivity decreases in obese patients 4
• ECG criteria may be affected by:
  • Left bundle branch block (LBBB)
  • Right bundle branch block (RBBB)
  • Left anterior fascicular block 1

Distinguishing Primary vs. Secondary LVH

• Assess for other causes of LVH:
  • Hypertension (24-hour ambulatory BP monitoring recommended)
  • Aortic stenosis
  • Athletic heart
  • Infiltrative diseases (amyloidosis, Fabry disease) 1, 2, 5

Common Pitfalls to Avoid

• Relying solely on ECG for diagnosis: ECG has limited sensitivity despite being a useful screening tool 4, 3
• Inadequate echocardiographic views: Multiple views including apical views are required to detect all patterns of hypertrophy 1
• Missing apical hypertrophy: This variant may be difficult to visualize with echocardiography but is evident with CMR 1
• Using dobutamine for stress testing: This can exacerbate obstruction and is not recommended in suspected HCM 2
• Failure to distinguish physiologic from pathologic hypertrophy: Athletic heart vs. HCM requires careful evaluation 1

Follow-up Recommendations

• Repeat echocardiography every 1-2 years in confirmed HCM 2
• Annual 12-lead ECG to evaluate for asymptomatic changes in conduction or rhythm 1, 2
• For family members of HCM patients: screening with ECG and echocardiography according to age-specific protocols 1

By following this systematic approach, LVH can be accurately diagnosed, allowing for appropriate risk stratification and management to reduce morbidity and mortality.