SIMULATION OF ATRIAL FLUTTER BY RAPID CORONARY SINUS PACING

In 5 human subjects and 7 canines, the coronary sinus was paced at rates of 250 to 350 per minute using an electrode catheter. Two of the dogs were similarly paced from the inferior left atrium. An arrhythmia was produced with the following electrocardiographic characteristics: (1) continuous atrial activity with P waves identical in spacing, size, and contour; (2) a suggestion of base line undulation, often with a sawtooth configuration, in Leads II, III, and aVF; (3) varying degrees of A-V block. The arrhythmia produced was not self-perpetuating and immediately ceased upon discontinuing pacing. The P-wave vector of this rhythm was directed superiorly, somewhat rightward, and anteriorly. This is similar to the P vectors of most cases of spontaneous clinical flutter, and also to those of both paced and spontaneous coronary sinus rhythms, and inferior left atrial rhythms. Thus, by rapid pacing of the coronary sinus, and the inferior left atrium, a unifocal atrial tachycardia was produced that resembles atrial flutter. Some cases of clinical atrial flutter may originate as a unifocal tachycardia originating from the coronary sinus or left atrium. © 1969.