Recurrent cardiac arrest caused by lateral medulla oblongata infarction.

Cardiac arrest is a rare complication in Wallenberg syndrome, despite the fact that the brainstem, especially the lower medulla, modulates sympathetic and parasympathetic activity. In the case reported here, a 45-year-old man was admitted with clinical symptoms of Wallenberg syndrome, including right sided hemiparesis secondary to dissection of the right vertebral artery. During the following days he experienced several spells of self limiting cardiac arrests, which made the implantation of a pacemaker necessary. Magnetic resonance imaging scan showed an infarction on the lower right and dorsolateral medulla. This might have affected the central sympathetic neurons which normally inhibit the nucleus of the solitary tract. The disinhibition of the nucleus tractus solitarii may have led to an increase of parasympathetic outflow resulting in bradycardia/asystolia. This case report describes a rare indication for transient or permanent therapy with a cardiac pacemaker in Wallenberg syndrome.