This QRS morphology has a typical left bundle branch block pattern, is irregular and does not meet the Brugada criteria for ventricular tachycardia (see the ventricular tachycardia review below).

With Mobitz type 1 second-degree heart block, the PR intervals get longer, and QRS waves are delayed and then dropped, which happens cyclically and adopts a regular pattern. For instance ...

The P waves appear sinus in origin and have no association with the QRS complexes indicating 3rd degree heart block (complete ... on a left bundle branch block pattern. This occurs since ...