title: Incomplete interpolation caused by sinoatrial pacemaker shift. A report of two cases.
abstract: Shortened return cycles after premature atrial stimulation (PAS) are commonly referred to as sinoatrial entrance block and exit delay at the sinoatrial junction or sinus-node reentries. In the 2 reported cases PAS at critical coupling intervals was followed by shortened return cycles characterized by a changed high right electrogram (and surface P waves in 1 case) and a normal sequence of atrial activation with unaltered intraatrial conduction. These changes lasted for some beats and a concomitant shorter or longer atrial cycle length was observed. Electrophysiological events furnish indirect evidence of sinoatrial pacemaker shift as a cause of incomplete interpolation in man.
mesh_terms: D000328:Adult; D001146:Arrhythmia, Sinus / Q000175:diagnosis* / Q000503:physiopathology; D004558:Electric Stimulation / Q000295:instrumentation / Q000379:methods; D004562:Electrocardiography; D006801:Humans; D008297:Male; D012849:Sinoatrial Node / Q000503:physiopathology*