Persistent Sick Sinus Syndrome Post-Guillain–Barré Syndrome Requiring AAIR Pacing

Guillain–Barré syndrome (GBS) is an acute, immune-mediated polyradiculoneuropathy with a triad of progressive limb weakness, sensory abnormalities, and areflexia following an infection. Autonomic dysfunction occurs in two-thirds of patients and significantly influences prognosis. While most autonomic disturbances, such as blood pressure fluctuations and arrhythmias, are transient and improve with neurological recovery. Severe or persistent bradyarrhythmias are rare and potentially fatal. We present a case of GBS with long-term sinus node dysfunction requiring permanent pacemaker insertion following complete motor recovery. The patient had recurrent presyncope and marked sinus pauses on Holter monitoring without any reversible etiology. Electrophysiological evaluation supported the diagnosis of sick sinus syndrome (SSS) due to chronic autonomic dysfunction. An atrial-based AAIR pacemaker was inserted considering the patient’s intact atrioventricular conduction and financial constraints. Electrophysiological evaluation supported the diagnosis of SSS. This case highlights the need for continuous cardiac monitoring in GBS, early recognition of autonomic complications, and timely intervention to prevent mortality. Cardiac monitoring should continue even after neurological recovery.