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 ...

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 Sun's counterclockwise rotation (as viewed from its north pole) originates from the initial spin of the solar nebula, a remnant of the larger cloud from which it formed. The direction of this spin ...