When electrical activity does not conduct through the His-Purkinje system, but instead travels from myocyte to myocyte, a longer time is necessary, and the QRS duration is widened. A widened QRS ...

This wide QRS complex tachycardia has a typical left bundle branch block pattern, but two things give the clue that this is ventricular tachycardia. There is a fusion beat (second from left ...

Second-degree AV block PR increment preceding a blocked P (Wenckebach) and narrow QRS Constant PR interval preceding blocked P PR increment (Wenckebach) preceding a blocked P and wide QRS 2:1 AV ...