Diagnosed when the QRS voltage exceeds predetermined limits. Multiple criteria exist including the following commonly used criteria:
- S in V1 + R in V5 or V6 greater than 35 mm (add 5mm for each decade below 40yr)
- R in V5 or V6 greater than 26mm
- R in aVL > 11mm (14mm in presence of left anterior fascicular block
- R in lead I + S in lead III greater than 25mm
