When Sleep Mode Becomes a Nightmare.

BACKGROUND

Atrioventricular node (AVN) ablation preceded by pacemaker insertion is a safe procedure used for both rate and symptom control in symptomatic atrial fibrillation.

CASE SUMMARY: This is a case of bradycardia-induced PMVT which occurred after AVN ablation, despite the presence of a VVI-R pacemaker inserted a few months prior. Lower pacing rates were allowed during the night due to 'sleep mode' being enabled. The nocturnal bradycardia resulted in ventricular escape rhythm with frequent ectopy, leading to 'R on T' mediated PMVT. Turning the sleep function off suppressed the ectopic activity and prevented further PMVT.

DISCUSSION: PMVT following AVN ablation has been well described in literature. Be it after AVN ablation, or when changing pacemaker programming, the common denominator is a relative bradycardic state which promotes ventricular ectopy and "R on T".