Frequency of spontaneous and inducible atrioventricular nodal reentry tachycardia in patients with idiopathic outflow tract ventricular arrhythmias.
OBJECTIVE
We sought to assess the frequency of spontaneous or inducible atrioventricular nodal reentry tachycardia (AVNRT) in patients referred for radiofrequency ablation (RFA) of idiopathic outflow tract ventricular arrhythmias.


BACKGROUND
In patients with no obvious heart disease, AVNRT and outflow tract ventricular tachycardia (VT) are the most frequently encountered supraventricular and ventricular tachycardias, respectively. An increased coexistence of the two arrhythmias has been recently suggested.


METHODS
In 68 consecutive patients referred for RFA of an idiopathic ventricular outflow tract arrhythmia, a stimulation protocol including repeated bursts of rapid atrial pacing, up to triple atrial extrastimuli during sinus rhythm and rapid ventricular pacing was performed before and after isoproterenol infusion following RFA of the ventricular arrhythmia. In patients with inducible AVNRT, RFA of the slow pathway was performed.


RESULTS
Of the 68 study patients, 17 (25%) had either spontaneous AVNRT documented prior to RFA of the ventricular arrhythmia (n = 4) or inducible AVNRT at the time of RFA of the ventricular arrhythmia (n = 13). AVNRT was induced by atrial pacing in 15 (88%) of 17 patients: in 3 patients without isoproterenol and in 12 patients during isoproterenol infusion. Uncomplicated RFA of the slow pathway was successfully achieved in all patients with inducible AVNRT.


CONCLUSIONS
Spontaneous or inducible AVNRT is relatively common in patients with idiopathic outflow tract ventricular arrhythmias. Atrial stimulation, especially when performed after isoproterenol infusion plays a major role in AVNRT inducibility. Although we performed RFA of the slow pathway in patients with inducible AVNRT and no prior tachycardia documentation, the question whether this is mandatory remains unsettled.
Topilski
Ian
I
Department of Cardiology, Tel-Aviv Sourasky Medical Center, and the Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
Glick
Aharon
A
Viskin
Sami
S
Belhassen
Bernard
B
D000293:Adolescent; D002304:Cardiac Pacing, Artificial; D017115:Catheter Ablation; D016009:Chi-Square Distribution; D004562:Electrocardiography; D005260:Female; D006801:Humans; D015994:Incidence; D007545:Isoproterenol; D008297:Male; D008875:Middle Aged; D018709:Statistics, Nonparametric; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000150:complications* / Q000503:physiopathology / Q000628:therapy; D017180:Tachycardia, Ventricular / Q000150:complications* / Q000503:physiopathology / Q000628:therapy
D007545:Isoproterenol