ECG. Left Ventricular Hypertrophy.

Left ventricular hypertrophy is an increase in the size of the left ventricle. When the wall of the left ventricle increases in thickness, the heights of the QRS complexes increase. Tall voltage is usually present in Leads I, aVL, V5 and V6. Tall voltage will be recorded in the form of tall R waves.

Likewise, when the myocardium as abnormally thickened and electrical activity takes longer to traverse throughout the whole heart, thus the duration of the QRS complex may be widened.

Also, repolarization may be affected via similar mechanisms which can result in abnormal ST segments or T waves. This is referred to as "LVH with strain" or "LVH with repolarization abnormality". The typical pattern with left ventricular hyertrophy includes deviation of the ST segment in the opposite direction of the QRS complex (discordance) and a typical T wave inversion pattern is present.

ECG Criteria

Sokolow-Lyon Criteria: Add the S wave in V1 plus the R wave in V5 or V6. If the sum is > 35 mm, then LVH is present.

Cornell criteria: Add the R wave in aVL and the S wave in V3. If the sum is > 28 mm in males or > 20 mm in females, then LVH is present.

Modified Cornell Criteria: Examine the R wave in aVL. If the R wave is > 12 mm in amplitude, then LVH is present.