Seizure Triggered by Sick Sinus Syndrome

Sick sinus syndrome (SSS) is a dysfunction of sinoatrial node resulting in symptomatic bradycardia or sinus pauses causing decreased cardiac output with cerebral hypoperfusion and usually presents as syncope, presyncope or fatigue. The occurrence of a seizure is very rare. A 69-year-old man suffered two episodes of generalised tonic-clonic seizures. MRI and electroencephalogram failed to reveal the cause of seizures. In the emergency room, he experienced presyncope simultaneous to bradycardia and sinus pauses. He was stabilised with atropine and dopamine infusion and underwent definitive therapy with a permanent dual-chamber pacemaker with complete symptom resolution. Diagnostic confounders include convulsive syncope and ictal bradycardia. Syncope may be accompanied by myoclonic jerks (convulsive syncope), but postictal confusion is absent. Bradycardia may be seen during the postictal period (ictal bradycardia syndrome), but protracted sinus dysfunction is not present. Hypoperfusion due to significant SSS triggered seizures in this patient who may have an underlying predisposition.