If the QRS complex is widened and downwardly deflected in lead V1, a left bundle branch block is present ... be difficult to distinguish from ventricular tachycardia because both cause a wide ...

Remember that T wave inversions and ST segment depression are normal in leads V1 to V3 in the presence of a right bundle branch block ... ventricular contractions that arise from the left ...

One can examine the initiation and termination of tachycardia for ... contractions [PACs], premature ventricular contractions [PVCs], intermittent bundle branch block, or changes in cycle length).

This is absolutely important when dealing with athletes showing ventricular arrhythmias with left bundle branch block morphology or 12-lead ECG ... non-sustained ventricular tachycardia (VT), ...