When the brain slows the heart—herpes encephalitis and sinus
Herpes simplex virus (HSV) encephalitis is a known cause of cognitive deterioration, neurological disturbances, and seizures though are rarely associated with sinus node dysfunction.

Authors present a 54-year-old man admitted to the hospital with a 10-day history of fever, confusion, and fatigue, 1 week following a transient loss of consciousness. An initial workup suggested HSV encephalitis and the patient was started on intravenous Acyclovir. Due to his episode of syncope, a 24?h Holter electrocardiogram monitoring was performed.

The Holter documented multiple episodes of sinus arrest, with a second episode of syncope noticed by the hospital staff concurrent with the last documented sinus arrest. Following antiviral treatment and resolution of the encephalitis they noticed complete resolution of sinus node dysfunction. They subsequently avoided permanent pacemaker implantation.

This case of proven HSV encephalitis complicated by sinus node arrest and syncope with complete resolution following antiviral treatment suggests no indication for permanent pacemaker implantation. This approach is consistent with data from previously reported cases.

Source: https://academic.oup.com/ehjcr/article/5/8/ytab254/6333696