Tachycardia Initiation by Dual-Mode PVC on Ambulatory ECG: Pattern Discovery and Invasive Electrophysiological Characteristics.

BACKGROUND

Mechanisms of premature ventricular complex (PVC)-induced long-RP tachycardia warrant investigation.

CASE SUMMARY: A 57-year-old man with palpitations underwent 24-hour ambulatory electrocardiogram (ECG). The recording showed 4,150 monomorphic PVCs and 800 episodes of long-RP tachycardia, all triggered by the same PVC morphology. Two initiation patterns emerged. One involved direct retrograde conduction, the other showed retrograde conduction only after PR prolongation. In both patterns, induction occurred across a broad range of PVC coupling intervals. Invasive electrophysiology study (EPS) then demonstrated slow-slow atrioventricular nodal re-entrant tachycardia (SS-AVNRT) involving multiple atrioventricular nodal pathways, consistent with the dual-mode patterns seen on ambulatory ECG. Ablation succeeded, with no recurrence at 6 months.

DISCUSSION: To our knowledge, this is the first reported case of SS-AVNRT to show distinctive PVC-induced tachycardia patterns on ambulatory ECG, corroborated by EPS.

TAKE-HOME MESSAGE: Ambulatory ECG patterns of PVC-triggered long-RP tachycardia may suggest a dual-pathway substrate for SS-AVNRT, warranting EPS confirmation.