Sokolow-Lyon Voltage Criteria: The most widely used ECG criteria for predicting Left Ventricular Hypertrophy (LVH). Uses standard 10mm/mV calibration (1 mm = 1 small box).
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Guidelines & Evidence
Clinical Details
Section 1
When to Use
When to Use
To screen for Left Ventricular Hypertrophy (LVH) on a standard 12-lead ECG
In the initial workup of hypertension, suspected aortic stenosis/regurgitation, or hypertrophic cardiomyopathy
Do Not Use If
Patient is under 35 years old (high rate of false positives), has a Bundle Branch Block (LBBB/RBBB), or has ventricular pacing. The criteria lose validity when normal ventricular depolarization is disrupted.
Section 2
Formula & Logic
Electrophysiological Basis
LVH increases the total muscle mass of the left ventricle. This generates a larger electrical vector directed posteriorly and to the left. On an ECG, this manifests as deeper negative deflections (S waves) in right-sided pre-cordial leads (V1/V2) and taller positive deflections (R waves) in left-sided leads (V5/V6, aVL, I).
The Criteria
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1. Measure the depth of the S wave (in mm) in lead V1.
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2. Measure the height of the R wave (in mm) in lead V5 and lead V6. Take whichever is taller.
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3. Add the two values. If the sum is ≥ 35 mm, LVH criteria are met.
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Optional / Independent: If the R wave in lead aVL is ≥ 11 mm, this alone also satisfies criteria for LVH.
Section 3
Pearls/Pitfalls
Performance Limitations
ECG criteria for LVH have notoriously poor sensitivity (often ~20-30%) but high specificity (~85-95%). A patient with severe concentric LVH on echocardiogram can easily have a completely normal ECG (e.g., if they are obese, which dampens the voltage). Therefore, a negative ECG absolutely DOES NOT rule out LVH.
Secondary Changes
True LVH often comes with "strain pattern": ST-segment depression and asymmetric T-wave inversion in the lateral leads (I, aVL, V5, V6). If voltage criteria are met AND a strain pattern is present, the specificity for actual anatomical hypertrophy approaches 100%.
Section 4
Evidence Appraisal
Original Publication
The ventricular complex in left ventricular hypertrophy as obtained by unipolar precordial and limb leads.
Sokolow M et al. • Am Heart J.. 1949;37(2):161-186. The landmark paper establishing the 35mm threshold.
