Lesson 21 of 21 · Advanced

Chamber Enlargement

Hypertrophied muscle generates more voltage and takes longer to repolarize. Voltage criteria are specific but not sensitive; echo is the gold standard.

01Left ventricular hypertrophy

Sokolow–Lyon: S in V1 + R in V5 or V6 ≥ 35 mm
Cornell: R in aVL + S in V3 > 28 mm (men) / > 20 mm (women)
R in aVL ≥ 11 mm

Tall R in V5 with 'strain': downsloping ST depression and asymmetric T inversion.

02Right ventricular hypertrophy

Right axis deviation
R > S in V1 (R ≥ 7 mm)
Deep S in V5–V6
Right atrial enlargement often coexists

03Atrial enlargement

P-wave morphology

Clinical pearl. Low voltage everywhere plus tachycardia: think pericardial effusion and look for electrical alternans.

Key takeaways

LVH: S V1 + R V5/6 ≥ 35 mm
Strain pattern = repolarization abnormality
RVH: RAD + dominant R in V1