ABSTRACT
BACKGROUND: Entrainment from the right ventricular (RV) apex and the base has been used to distinguish atrioventricular reentrant tachycardia (AVRT) from atrioventricular nodal reentry tachycardia (AVNRT). The difference in the entrainment response from the RV apex in comparison with the RV base has not been tested. METHODS: Fifty-nine consecutive patients referred for ablation of supraventricular tachycardia (SVT) were included. Entrainment of SVT was performed from the RV apex and base, pacing at 10-40-ms faster than the tachycardia cycle length. SA interval was calculated from stimulus to earliest atrial electrogram. Ventricle to atrium (VA) interval was measured from the RV electrogram (apex and base) to the earliest atrial electrogram during tachycardia. The SA-VA interval from apex and base was measured and the difference between them was calculated. RESULTS: Thirty-six AVNRT and 23 AVRT patients were enrolled. Mean age was 44 ± 12 years; 52% were male. The [SA-VA]apex-[SA-VA]base was demonstrable in 84.7% of patients and measured -9.4 ± 6.6 in AVNRT and 10 ± 11.3 in AVRT, P < 0.001. The difference was negative for all AVNRT cases and positive for all septal accessory pathways (APs). CONCLUSION: The difference between entrainment from the apex and base is readily performed and is diagnostic for all AVNRTs and septal APs.
Subject(s)
Tachycardia, Atrioventricular Nodal Reentry/diagnosis , Tachycardia, Supraventricular/diagnosis , Accessory Atrioventricular Bundle/diagnosis , Accessory Atrioventricular Bundle/physiopathology , Adult , Catheter Ablation , Diagnosis, Differential , Electrocardiography/methods , Female , Heart Conduction System/physiopathology , Heart Conduction System/surgery , Humans , Male , Middle Aged , Tachycardia, Atrioventricular Nodal Reentry/classification , Tachycardia, Atrioventricular Nodal Reentry/physiopathology , Tachycardia, Atrioventricular Nodal Reentry/surgery , Tachycardia, Supraventricular/physiopathology , Tachycardia, Supraventricular/surgeryABSTRACT
BACKGROUND: The differential diagnosis of wide complex tachycardia (WCT) with 1:1 atrioventricular (AV) relationship is broad. Accurate identification of the tachycardia mechanism is essential for successful ablation. We suggest a simple pacing maneuver that can immediately clarify the tachycardia mechanism in the electrophysiology laboratory. METHODS: Eight consecutive patients (four males, 32 +/- 14 years) demonstrating stable sustained WCT with persistent 1:1 AV relationship during electrophysiologic testing were included in this study. During the tachycardia, atrial overdrive pacing was performed. The following responses were observed: (1) a change of the QRS morphology during atrial pacing and (2) the first return electrogram of the tachycardia, whether occurring in the atrium (AVA response) or in the ventricle (AVVA response). RESULTS: Atrial overdrive pacing was successfully performed in all patients. It was associated with either a change or narrowing of the QRS in all ventricular tachycardia (VT) patients but not in supraventricular tachycardia (SVT) patients. All VT patients had an AVVA response upon cessation of atrial overdrive pacing as opposed to AVA response in SVT patients, P = 0.029. CONCLUSION: The response to atrial overdrive pacing during WCT with 1:1 AV relationship can rapidly diagnose or rule out VT as a mechanism of tachycardia.
