Viral encephalitis associated with reversible asystole due to sinoatrial arrest.

We report a case of sinoatrial node block associated with syncopal episodes that required a temporary pacemaker. Magnetic resonance imaging (MRI) of the brain showed lesions of both temporal lobes consistent with viral encephalitis, presumably due to herpes simplex virus (HSV). The patient quickly recovered with intravenous acyclovir (Zovirax) therapy. Patients with presumed encephalitis might benefit from cardiac monitoring for possible associated cardiac arrhythmia. A permanent pacemaker is rarely required, since recovery is spontaneous in the majority of these cases.