ECG Findings of Left Ventricular Hypertrophy
The diagnosis of LVH on ECG relies primarily on voltage-based criteria, with the Sokolow-Lyon criterion (S wave in V1 + R wave in V5 or V6 > 35 mm) and Cornell voltage criteria (S wave in V3 + R wave in aVL > 28 mm for men, > 20 mm for women) being the most recommended approaches, both offering high specificity of 85-90%. 1, 2
Primary Voltage Criteria
The following voltage-based criteria are used for diagnosing LVH:
Sokolow-Lyon Index: S wave in V1 + R wave in V5 or V6 ≥ 3.5 mV (35 mm) is the classic threshold recommended by the American College of Cardiology 1, 2
Cornell Voltage Criteria:
Cornell Voltage-Duration Product: Cornell voltage × QRS duration > 2440 mm·ms provides additional diagnostic accuracy 1
Additional voltage thresholds: R wave in aVL > 1.1 mV, R wave in V5 or V6 > 2.6 mV, or sum of R waves in V5 + V6 > 4.5 mV 2
Romhilt-Estes Point Score System
This comprehensive scoring system assigns points for multiple ECG features, with ≥5 points indicating definite LVH and 4 points indicating probable LVH 2:
- Voltage criteria (3 points): Any limb lead R or S wave ≥ 2.0 mV, S wave in V1 or V2 ≥ 3.0 mV, or R wave in V5 or V6 ≥ 3.0 mV 2
- The system incorporates QRS amplitude, ST-T abnormalities, left axis deviation, QRS duration, and intrinsicoid deflection 1
Supporting ECG Findings (Non-Diagnostic Alone)
These findings strengthen the diagnosis when voltage criteria are met:
ST-T wave abnormalities: Lateral ST depression with T wave inversion (secondary ST-T changes) strongly support LVH diagnosis and are associated with larger left ventricular mass and higher cardiovascular risk 1, 2
Left atrial abnormalities: P-wave changes suggesting left atrial enlargement frequently accompany LVH, particularly in hypertensive heart disease 1, 2
Left axis deviation: QRS axis more negative than -30° may accompany LVH but should not be used alone for diagnosis 1, 2
QRS duration prolongation: Often accompanies LVH and can support the diagnosis 1, 2
QT interval prolongation: Slight QT prolongation often accompanies LVH 2
Special Circumstances and Diagnostic Challenges
Left Bundle Branch Block (LBBB)
- ECG diagnosis of LVH should generally NOT be attempted in complete LBBB 1, 2
- If attempted, use QRS duration > 155 ms combined with precordial voltage criteria 2
- Research suggests that parameters based on S wave amplitude in V2 or V3 combined with R wave in aVL, V5, or V6 may have clinical value, but require recalibrated cut-points 3
Right Bundle Branch Block (RBBB)
- Sensitivity of voltage criteria is decreased in RBBB 1
- Specific criteria can be used: SV1 > 2 mm, RV5 or V6 > 15 mm, and QRS axis left of -30° with S in lead III 1, 2
Left Anterior Fascicular Block (LAFB)
- R wave amplitude in leads I and aVL are NOT reliable for LVH diagnosis 2
- Use criteria incorporating S wave depth in left precordial leads (V5, V6) instead 2
Factors Affecting ECG Diagnosis
Age: QRS voltages decline with increasing age; standard criteria best apply to adults over 35 years 1
Gender: Women have slightly lower upper limits of QRS voltage than men, necessitating gender-specific criteria 1
Body habitus: Obesity increases left ventricular mass but decreases QRS voltage due to increased distance between the heart and recording electrodes 1
Important Clinical Caveats
- Sensitivity limitations: All ECG voltage criteria have relatively low sensitivity (ranging from 14-41% in various studies), meaning many patients with true LVH will have normal ECG voltage 4, 5, 6, 7
- Specificity is high: When voltage criteria are met, specificity is 85-90%, making positive findings reliable 1
- The majority of patients with increased left ventricular mass do not have increased QRS voltage, suggesting that electrical effects and increased mass may be independent phenomena related to underlying pathology 5
- In hypertrophic cardiomyopathy specifically, ECG criteria perform poorly with maximal diagnostic accuracy of only 58-86% depending on the pattern of hypertrophy 6, 7