Distinguishing STEMI from Left Ventricular Hypertrophy (LVH)

Left ventricular hypertrophy (LVH) is one of the most common causes of false-positive STEMI activation, responsible for up to 18% of all STEMI alarms. Because LVH produces secondary repolarization abnormalities (ST elevation, ST depression, T-wave inversions), it can closely mimic acute myocardial infarction.

Correctly distinguishing true STEMI from LVH-related ST abnormalities helps avoid unnecessary catheterization lab activation, reduces costs, and prevents procedure-related risk.

Primary References:

• LVH mistaken for STEMI – EMS1
• LITFL – LVH ECG Library
• American Heart Association STEMI Guidelines: AHA STEMI Management

LVH increases QRS voltage and alters depolarization/repolarization. This leads to:

• High-voltage QRS complexes
• Secondary ST-T abnormalities
• Discordant ST elevation or depression
• T-wave inversions (“strain pattern”)

These changes may resemble ischemia but often reflect ventricular overload, not coronary occlusion.

Common diagnostic features include:

• Voltage criteria (Sokolow-Lyon, Cornell)
• High-amplitude R waves in lateral leads (I, aVL, V5, V6)
• Deep S waves in V1–V3
• ST depression in lateral leads
• T-wave inversions (“strain”) in lateral leads
• Slight upward-sloping ST elevation in V1–V3 (false anterior STEMI appearance)

Voltage Criteria Examples:

• Sokolow-Lyon: S in V1 + R in V5/V6 ≥ 35 mm
• Cornell: R in aVL > 11 mm (men > 28 mm; women > 20 mm)

Reference: ECG Criteria for LVH – Merck Manual

Signs that support acute coronary occlusion:

• New ST-segment elevation at the J-point
• Reciprocal ST depression in opposite leads
• New Q waves (pathological)
• Hyperacute T waves
• Convex (“tombstone”) ST elevation
• Consistent pattern across contiguous leads

True STEMI usually shows proportionate ST-segment elevation relative to QRS amplitude.

STEMI recognition becomes difficult because:

• LVH produces baseline ST elevation (especially V1–V3)
• LVH produces ST depression and T-wave inversion resembling ischemia
• QRS voltages distort ST-segment measurements
• STEMI criteria have low specificity in LVH

A small retrospective study showed that traditional STEMI criteria have only 58% specificity in patients with LVH.

Recent evidence suggests that two findings significantly improve diagnostic accuracy in LVH:

• ST elevation > 25% of the QRS amplitude (peak-to-nadir)
• ST elevation in ≥ 3 contiguous leads OR T-wave inversions in anterior leads

These criteria:

• Have similar sensitivity to classic STEMI rules
• Improve specificity to 91%
• Reduce false activations by ~35%

Reference: LVH mistaken for STEMI – EMS1

• Always look at the ST/T ratio relative to QRS amplitude.
• LVH typically shows discordant ST depression or elevation that is proportionate to QRS size.
• STEMI typically shows disproportionate ST elevation, often with reciprocal changes.
• Compare with prior ECG if available—LVH patterns are usually chronic.
• When in doubt, obtain serial ECGs and integrate with symptoms and troponin levels.
• In the presence of clear ischemic symptoms, never dismiss possible STEMI solely due to LVH.

• LVH is the most common cause of false-positive STEMI interpretation.
• Voltage overload causes ST changes that resemble ischemia.
• Using proportionate ST elevation (>25%), contiguous lead analysis, and recognition of strain improves accuracy.
• True STEMI usually includes reciprocal changes, hyperacute T waves, and disproportionate ST elevation.
• Proper distinction prevents unnecessary catheterization lab activation and supports safe, evidence-based care.