What are the different types of left ventricular hypertrophy (LVH)?

Different Types of Left Ventricular Hypertrophy

Classification Based on Geometry

Left ventricular hypertrophy (LVH) can be classified into four distinct geometric patterns based on left ventricular mass and relative wall thickness, each with different clinical implications and prognosis. 1

The four main types of LVH based on geometry are:

1. Normal Geometry: Normal LV mass and normal relative wall thickness (RWT)
2. Concentric Remodeling: Normal LV mass with increased RWT (≥0.42)
3. Concentric Hypertrophy: Increased LV mass with increased RWT (≥0.42)
4. Eccentric Hypertrophy: Increased LV mass with normal RWT (<0.42)

Key Measurements for Classification

• Relative Wall Thickness (RWT): Calculated as (2 × posterior wall thickness)/LV end-diastolic diameter
• LV Mass Index: LV mass normalized to body surface area (g/m²) or height^2.7 (g/m^2.7)
• Normal Values:
  • Men: LV mass index ≤115 g/m² or ≤48 g/m^2.7
  • Women: LV mass index ≤95 g/m² or ≤44 g/m^2.7

Expanded Four-Tiered Classification

A more refined classification system incorporates LV dilatation in addition to concentricity, resulting in four distinct patterns 2, 3:

1. Thick Hypertrophy (Concentric Nondilated): Increased concentricity with normal LV volume
2. Dilated Hypertrophy (Eccentric Dilated): Normal concentricity with increased LV volume
3. Both Thick and Dilated Hypertrophy (Concentric Dilated): Increased concentricity with increased LV volume
4. Indeterminate Hypertrophy (Eccentric Nondilated): Normal concentricity with normal LV volume

This expanded classification has prognostic significance, as patients with dilated forms of hypertrophy typically have worse outcomes, higher natriuretic peptide levels, and lower ejection fractions 2.

Classification Based on Severity

LVH can also be categorized by severity 1:

• Mild LVH:

  • Men: 116-131 g/m² or 49-55 g/m^2.7
  • Women: 96-108 g/m² or 45-51 g/m^2.7

• Moderate LVH:

  • Men: 132-148 g/m² or 56-63 g/m^2.7
  • Women: 109-121 g/m² or 52-58 g/m^2.7

• Severe LVH:

  • Men: ≥149 g/m² or ≥64 g/m^2.7
  • Women: ≥122 g/m² or ≥59 g/m^2.7

Etiological Classification

LVH can be classified based on underlying cause 1, 4:

1. Physiological LVH

• Athletic Heart: Adaptive response to exercise training
  • Features: Proportional chamber enlargement, normal diastolic function, normal EF

2. Pathological LVH

A. Pressure Overload

• Hypertension: Most common cause of LVH
• Aortic Stenosis: Leads to concentric LVH
• Hypertrophic Cardiomyopathy (HCM): Genetic disorder with asymmetric septal hypertrophy

B. Volume Overload

• Valvular Regurgitation: Mitral or aortic regurgitation
• High-output States: Anemia, arteriovenous fistula

C. Infiltrative/Storage Diseases

• Amyloidosis: Characterized by low voltage ECG despite increased wall thickness
• Fabry Disease: X-linked lysosomal storage disorder
• Glycogen Storage Diseases: Pompe, Danon disease

D. Endocrine Disorders

• Acromegaly: Growth hormone excess
• Pheochromocytoma: Catecholamine excess
• Thyroid Disease: Both hypo- and hyperthyroidism

E. Drug-Induced

• Anabolic Steroids
• Tacrolimus
• Hydroxychloroquine

Distinguishing Features of HCM vs. Other Forms of LVH

Hypertrophic cardiomyopathy (HCM) has specific characteristics that differentiate it from other forms of LVH 1:

• Definition: LV wall thickness ≥15 mm in one or more segments that cannot be explained by loading conditions
• Distribution: Often asymmetric with predominant involvement of the basal septum
• Features: May include myocardial crypts, elongated mitral valve leaflets, apically displaced papillary muscles
• Genetics: Associated with sarcomeric protein gene mutations

Clinical Implications

The different types of LVH have varying prognostic implications:

• Concentric Hypertrophy: Highest risk for adverse cardiovascular events
• Eccentric Dilated Hypertrophy: Associated with progression to heart failure
• Concentric Remodeling: Intermediate risk
• Eccentric Nondilated (Indeterminate) Hypertrophy: Similar risk profile to normal geometry 3

Diagnostic Approach

When evaluating LVH, consider:

1. Echocardiography: Primary tool for assessing LV geometry and mass
2. CMR (Cardiac MRI): More accurate for LV mass measurement and tissue characterization
3. ECG: May show voltage criteria for LVH but has limited sensitivity
4. Clinical Context: Age, blood pressure, athletic status, family history
5. Genetic Testing: Consider in suspected HCM, especially with family history

Pitfalls in Classification

• Wall thickness of 13-14 mm represents a "gray zone" that may be physiological (athlete's heart) or pathological
• Coexisting conditions (e.g., hypertension and HCM) can complicate classification
• Elderly patients may have isolated basal septal hypertrophy that doesn't represent HCM
• Advanced disease stages may show wall thinning despite initial hypertrophy

Understanding these different types of LVH is crucial for appropriate management strategies and risk stratification in patients with cardiovascular disease.