We report the case of a patient with congenital sick sinus syndrome complicated by atrial fibrillation and embolic stroke 23 years after the initial diagnosis, at the age of 34 years. Treatment with a dual-chamber pacemaker and oral anticoagulation were initiated; further follow-up was uneventful but pacemaker diagnostics constantly documented asymptomatic recurrences of paroxysmal atrial fibrillation.