Table 1.

ECG characteristics of left bundle branch block.

•Length of QRS complex >120 ms •Left axis deviation (−120° tot −30°) •ST segment and T wave is discordant with QRS complex •Deep and broad S wave in leads V1-V3 with (discordant) STE and positive T wave, sometimes also inferior •High R wave in lateral leads (I, aVL, V5-V6) with (discordant) ST-depression and T wave inversion •R-transition precordial leads displaced to lateral, sometimes with Q wave up to lead V4-V5