Emergency Medicine · Cardiology

4-Variable Subtle LAD Occlusion Formula calculator

Enter the published formula inputs below to calculate and interpret this score.

Clinical inputs

Bazett-corrected QT interval

Allowed range: 250–700 ms

Computerized Bazett QTc in milliseconds.

QRS amplitude in V2

Allowed range: 0–60 mm

Entire QRS amplitude in lead V2, R wave plus S wave, in millimeters.

R-wave amplitude in V4

Allowed range: 0–60 mm

R-wave amplitude in lead V4, in millimeters.

ST elevation at 60 ms in V3

Allowed range: 0–10 mm

ST elevation 60 milliseconds after the J point in lead V3, in millimeters, measured from the PR segment.

Result

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Primary source

Driver BE et al. A new 4-variable formula to differentiate normal variant ST segment elevation in V2-V4 (early repolarization) from subtle left anterior descending coronary occlusion. J Electrocardiol. DOI: 10.1016/j.jelectrocard.2017.04.005. PMID: 28460689. The formula is 0.052 × Bazett QTc in milliseconds − 0.151 × QRS amplitude in V2 − 0.268 × R-wave amplitude in V4 + 1.062 × ST elevation 60 ms after the J point in V3. The same paper measures ST elevation in millimeters, and the QRS amplitudes use that millimeter scale. The cutoff with the highest accuracy was 18.2 or higher (sensitivity 88.8%, specificity 94.7%). (2017)

Scope: ECGs in which the question is subtle LAD occlusion versus normal-variant ST elevation of at least 1 mm in V2–V3. Obvious anterior STEMI was excluded from the derivation.

Last reviewed 2026-10-17

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Professional use only

For qualified clinicians. Independently verify inputs, calculations, source guidance, and applicability before any clinical action. This calculator does not replace clinical judgment.

Source: Driver BE et al. A new 4-variable formula to differentiate normal variant ST segment elevation in V2-V4 (early repolarization) from subtle left anterior descending coronary occlusion. J Electrocardiol. DOI: 10.1016/j.jelectrocard.2017.04.005. PMID: 28460689. The formula is 0.052 × Bazett QTc in milliseconds − 0.151 × QRS amplitude in V2 − 0.268 × R-wave amplitude in V4 + 1.062 × ST elevation 60 ms after the J point in V3. The same paper measures ST elevation in millimeters, and the QRS amplitudes use that millimeter scale. The cutoff with the highest accuracy was 18.2 or higher (sensitivity 88.8%, specificity 94.7%). (2017)

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Clinical inputs

Bazett-corrected QT interval (ms)Accepted range: 250 to 700
QRS amplitude in V2 (mm)Accepted range: 0 to 60
R-wave amplitude in V4 (mm)Accepted range: 0 to 60
ST elevation at 60 ms in V3 (mm)Accepted range: 0 to 10

Primary source

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