Diagnostic utility of early premature ventricular complexes in differentiating atrioventricular reentrant and atrioventricular nodal reentrant tachycardias

Background: His-refractory premature ventricular complexes perturbing a supraventricular tachycardia (SVT) establish the presence of an accessory pathway (AP). Earlier premature ventricular complexes (ErPVCs) may perturb SVTs but are considered nondiagnostic.

Objective: The purpose of this study was to test the hypothesis that an ErPVC will always show a difference >35 ms in its advancement of the next atrial activation during atrioventricular nodal reentrant tachycardia (AVNRT). During atrioventricular reentrant tachycardia (AVRT), a PVC delivered close to the circuit can result in greater advancement of atrial activation due to retrograde conduction via an AP. Thus, an AP response, defined as ErPVC (H₁S₂) advancing the subsequent atrial activation (A₁-A₂) more than this minimum difference (A₁A₂ ≤ H₁S₂+35 ms), establishes the presence of an AP.

Methods: Sixty-five consecutive patients with SVT were retrospectively evaluated. ErPVCs were defined when the ventricular pacing stimulus was >35 ms ahead of the His during tachycardia.

Results: Among the 65 cases, 43 were AVNRT and 22 AVRT. Fourteen AVRT cases had an AP response with a mean H₁S₂+35 ms of 336 ± 58 ms and A₁A₂ of 309 ± 51ms. No AVNRT cases had an AP response. The specificity of an AP response to ErPVC in predicting AVRT was 100%.

Conclusion: An AP response to PVCs (A₁A₂ ≤ H₁S₂+35 ms) is 100% specific for the presence of an AP.