When evaluating the 12-lead for signs of biventricular hypertrophy, the clinician looks for:⁸

Criteria 1: Sokolow-Lyon voltage:⁹ S_V1 + R_V5(or R_V6) > 35 mm combined with a QRS right axis deviation in patients older than 30 years of age. 

Criteria 2: S_V6 ≥ 7 mm (without RBBB); this finding can also present in patients with isolated RVH

Criteria 3: Presence of RVH patterns + left atrial enlargement with a P duration of ≥ 0.12 seconds

• S/R ≥ 1 in V₅/V₆ + LA enlargement
• S_V6 ≥ 7 mm + LA enlargement
• ÅQRS_F > +90° + LA enlargement (if RBBB is present, then the ÅQRS_F
•  is calculated on the first 0.06 seconds of the QRS)

This criterion has a specificity of 80% with extremely low sensitivity. Echocardiography is generally required to confirm a diagnosis.

A shallow S_V1 and a deep S_V2 are additional ECG characteristics of biventricular hypertrophy (see Figure 2). The shallow S_V1 is caused by the cancellation of vectors between the extremely large right and left ventricles. This cancellation phenomenon is not apparent in V₂ because of its projection, which leads to a deep S_V2 instead.

Inadvertent lead placement of V₁ can also cause these findings if the lead is connected too high, too low, or too far to the lateral side of the patient.

Biventricular Hypertrophy With Large Biphasic Complexes

12-Lead ECG of a Pediatric Patient Born With a Ventricular Septal Defect