left bundle branch block

List the diagnostic criteria for left bandle branch block:

1. The specifically broadened R in 1, aVL, V5, and V6, which shows an M configuration, or the famous " broken-off sugar loaf";
2. The upper transition point in v6 is located more than 55 ms away from the beginning of the R wave;
3. In the chest wall leads, the latest negative motion of the R wave will be found in V5 or V6.