6. AVNRT: Electrophysiological Aspects and Ablation Results

Background During a supraventricular tachycardia an eccentric retrograde atrial activation usually suggests a left side accessory pathway (AP) Aim of the Study To report cases AVNRT with eccentric retrograde atrial activation. Methods Among 526 patients (pts) referred for electrophysiological evaluation for recurrent supraventricular tachycardia, we selected 6 pts (2 males, mean age 39±14 yrs) with AV node reentrant tachycardia (AVNRT) showing an eccentric retrograde atrial activation during tachycardia. An AT was ruled out by VAV response during entrainment by ventricular pacing. Pacing maneuvers were employed such as ventricular pre-excitation during atrial pacing, advancement of atrial activation by a premature ventricular contraction during His refractoriness, recording of an AP, lengthening of VA interval during bundle branch block to rule out the conduction over an AP. Ablation aiming at the slow AV nodal pathway potential was successful in eliminating and preventing tachycardia inducibility in all patients. Conclusions Detailed electrophysiological evaluation is required for correct diagnosis and elimination of tachycardia is usually achieved by ablating the slow AV nodal pathway at the right posteroseptal area.