Two patients who presented by scalar ECG with an A V junctional tachycardia were demonstrated during an electrophysiologic evaluation to have an atrial tachycardia without P waves in the surface ECG. Case 1 had an atrial tachycardia that conducted through the A V node with a Wenckebach block. Atrial activity was recorded only from the proximal portion of the coronary sinus and from right atrial areas near the tricuspid valve. Case 2 had an atrial tachycardia that abruptly began and terminated following carotid sinus massage. Atrial activity was recorded only in the coronary sinus os, and pacing at that site resulted in atrial capture, with Wenckebach conduction to the ventricles. These observations demonstrate that an atrial tachycardia without P waves can simulate A V junctional tachycardia with or without Wenckebach block. Such findings may have a bearing on some important electrophysiologic concepts such as the origin of A V junctional rhythms and the need for atrial participation in A V nodel re entry.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine
- Physiology (medical)