The normal P wave is biphasic in lead: (A) V1, (B) LII, (C) aVF, (D) aVR
Answer is A. The normal P wave in lead V1 may be biphasic with a positive component reflecting right atrial depolarization, followed by a small (<1 mm2 ) negative component reflecting left atrial depolarization. Ref Harrison 20th edition pg 1455