Single diagnostic pacing maneuver for supraventricular tachycardia

Background: Diagnostic supraventricular tachycardia (SVT) features and pacing maneuvers tend to be specific but insensitive. Therefore, diagnosis often requires the integration of multiple pieces of information and/or pacing maneuvers, which adds to the complexity of catheter ablation procedures. Objective: The purpose of this study was to determine if a single diagnostic pacing maneuver, namely, ventricular overdrive pacing including a basal pacing site near the earliest atrial activation, provides a definitive SVT diagnosis in nearly all patients. Methods: Sixty-seven consecutive patients with SVT undergoing catheter ablation at two institutions were prospectively studied. Results: Overdrive ventricular pacing provided the correct diagnosis in 91% of all patients and in 100% of patients when pacing accelerated the atrium to the pacing cycle length. Fusion due to wavefront collision in the ventricles or distal conduction system was 73% sensitive and 100% specific for accessory pathway-mediated SVT. Basal pacing was superior to pacing from the right ventricular apex for distinguishing accessory pathway-mediated SVT from AV nodal reentrant tachycardia. Conclusion: Overdrive ventricular pacing is a highly effective single diagnostic pacing maneuver for sustained SVT. Basal pacing sites near the earliest atrial activation are superior to the right ventricular apex.