In a “normal” electrocardiogram (ECG), the transition of the QRS axis in the precordial leads occurs between leads V 3 and V 4 (i.e., there is a dominant S in V 3 and a dominant R in V 4).
The diagnosis is NSR, Mobitz type I second-degree atrioventricular (AV) block (Wenckebach), nonconducted (blocked) PACs, and early transition (counterclockwise rotation). The rhythm is irregular, but ...