This calculator is for general information and education. It is not medical advice and does not replace the judgment of a doctor, nurse or pharmacist who knows the full clinical picture.
Why the ECG looks for big voltages
When the wall of the left ventricle thickens, usually because it has pumped against high blood pressure or a narrowed aortic valve for years, it produces larger electrical forces. On the ECG this shows as tall R waves in the left-sided leads and deep S waves in the right-sided leads. Several voltage criteria turn this into numbers. They were developed against autopsy or echocardiography findings and remain the routine screening tool, even though echocardiography or cardiac MRI is needed to confirm.
The criteria in this calculator
- Sokolow-Lyon index: S in V1 + R in V5 or V6 (the taller). Positive at 35 mm or more.
- Cornell voltage: R in aVL + S in V3. Positive above 28 mm in men and 20 mm in women.
- Cornell product: (R aVL + S V3, plus 6 mm in women) × QRS duration in ms. Positive at 2,440 mm·ms or more.
- R wave in aVL of 11 mm or more on its own.
Amplitudes are measured at the standard gain of 10 mm per mV.
Example
A 60-year-old man has S V1 15 mm, R V5 20 mm, R V6 18 mm, R aVL 8 mm, S V3 14 mm and a QRS of 100 ms:
- Sokolow-Lyon: 15 + 20 = 35 mm, positive
- Cornell voltage: 8 + 14 = 22 mm, below 28, negative
- Cornell product: 22 × 100 = 2,200 mm·ms, negative
- 1 criterion out of 4
For a woman with the same tracing, Cornell voltage would be positive (above 20 mm) and the product (22 + 6) × 100 = 2,800 mm·ms positive too, giving 3 criteria.
Reading the result
The ECG criteria are specific but insensitive: a positive result makes LVH likely, while a negative ECG does not rule it out. The Sokolow-Lyon index tends to be falsely positive in young, thin or athletic people with thin chest walls, while Cornell criteria perform better in older and obese patients. Signs of strain (ST depression and T-wave inversion in V5 and V6) and left atrial enlargement add weight to the diagnosis.
What to do next
LVH found on an ECG is a reason to check blood pressure carefully, examine the heart valves and request an echocardiogram. Treating the cause, above all hypertension, can make the hypertrophy regress and lowers the risk of heart failure, arrhythmia and stroke.