Causes and ECG Changes of Concentric and Eccentric Left Ventricular Hypertrophy
Concentric and eccentric left ventricular hypertrophy (LVH) have distinct causes and characteristic ECG findings, with concentric LVH typically showing more pronounced voltage criteria and ST-T abnormalities.
Concentric LVH
Causes
- Pressure overload conditions:
- Hypertension (most common cause) 1
- Aortic stenosis
- Hypertrophic cardiomyopathy
- Coarctation of aorta
Pathophysiology
- Characterized by increased wall thickness with preserved chamber geometry 1
- Symmetrical thickening of ventricular walls
- Increased relative wall thickness with increased left ventricular mass 1
- Strongest predictor of increased cardiovascular risk among LVH patterns 1
ECG Changes
- Increased QRS voltage (primary finding)
- Secondary ST-T abnormalities ("strain pattern") 2
- J-point depression
- Upwardly convex, downsloping ST segment depression
- Asymmetrical T-wave inversion
- QRS duration often increased 2
- Left axis deviation may be present 2
- P-wave abnormalities suggesting left atrial enlargement 2, 1
- Slight QT interval prolongation 2
Eccentric LVH
Causes
- Volume overload conditions:
- Aortic regurgitation
- Mitral regurgitation
- Dilated cardiomyopathy
- High-output states (anemia, arteriovenous fistula)
- Athletic heart (physiological adaptation)
Pathophysiology
- Characterized by chamber dilatation with proportional wall thickening
- Can be further classified into:
ECG Changes
- Generally less pronounced voltage criteria than concentric LVH
- QRS voltage may still meet LVH criteria
- Less prominent ST-T abnormalities compared to concentric LVH
- Left atrial abnormalities may be present
- QRS duration may be increased
- Left axis deviation can occur
- Eccentric non-dilated LVH has been associated with lower cardiovascular risk compared to other forms of LVH 3
Clinical Significance and Progression
Risk Stratification
- Concentric LVH carries higher cardiovascular risk than eccentric LVH 1, 3
- Eccentric non-dilated LVH appears to have the lowest risk among LVH patterns 3
- Presence of ST-T abnormalities with LVH indicates higher cardiovascular risk 2, 4
Progression
- Approximately 13% of patients with concentric LVH and normal ejection fraction progress to systolic dysfunction over 3 years 5
- Risk factors for progression to systolic dysfunction include:
- Interval myocardial infarction (most common - 43% of cases)
- QRS prolongation >120 ms
- Elevated arterial impedance 5
Monitoring
- Serial ECG evaluation is valuable for risk assessment
- Regression of ECG LVH during treatment is associated with:
- 14-17% lower rates of cardiovascular events
- Reduced risk of sudden cardiac death
- Lower incidence of atrial fibrillation
- Decreased heart failure hospitalizations 4
Diagnostic Pitfalls
Confounding Factors
- Obesity can increase left ventricular mass but decrease QRS voltage 2
- Age affects normal QRS axis ranges 1
- Gender differences in voltage criteria (women have lower voltage thresholds) 2
Conduction Abnormalities
- Left bundle branch block complicates LVH diagnosis 2
- Left anterior fascicular block alters R-wave amplitude in leads I and aVL 2
- In left anterior fascicular block, criteria that include S-wave depth in left precordial leads improve LVH detection 2
Recommendations
- Use validated criteria without deviation from established formulas 2
- Adjust criteria for gender, race, and body habitus when validated adjustments exist 2
- Consider echocardiography for more accurate assessment of LVH patterns 1
- Avoid terms like "strain," "systolic," and "diastolic" in LVH diagnostic statements 2
- Use caution when diagnosing LVH in the presence of complete LBBB 2
By understanding the distinct causes and ECG patterns of concentric and eccentric LVH, clinicians can better assess cardiovascular risk and guide therapeutic interventions aimed at regression of LVH and prevention of adverse outcomes.