title: Negative P waves in lead V6 during right ventricular pacing.
abstract: A negative P wave in lead V6 has been proposed as the most reliable criterion of left atrial rhythm, useful in differentiating it from nodal arrhythmias. In this report the electrocardiograms of two patients with right ventricular paced rhythms with 1:1 retrograde atrial capture are shown. The retrograde P waves inscribed after the ORS were negative in polarity in lead V6 in both cases. This documents that an impulse entering the atria from the AV junction can be associated with rightwardly oriented P waves and suggests that the proposed criterion for left atrial rhythm is unreliable.
mesh_terms: D000368:Aged; D004558:Electric Stimulation; D004562:Electrocardiography; D005260:Female; D006325:Heart Atria / Q000503:physiopathology; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D008875:Middle Aged; D010138:Pacemaker, Artificial