Complete atrioventricular dissociation and sinus arrest after pheochromocytoma resection

Introduction: Although preoperative bradycardia has been reported in several pheochromocytoma cases, postoperative bradycardia has not. This is the first case report of complete atrioventricular dissociation and sinus arrest occurring after pheochromocytoma resection.

Case presentation: A 38-year-old woman was referred for a left adrenal incidentaloma. Twenty-four hour urinary collection showed elevated noradrenaline. Iodine-123-meta-iodobenzylguanidine scintigraphy showed high tracer uptake in the left adrenal region. Open left adrenalectomy was performed, and histopathological examination confirmed the diagnosis of pheochromocytoma. Thirty minutes following surgery, complete atrioventricular dissociation and sinus arrest developed. Vagal reflex attenuation due to decreased noradrenaline after tumor removal and perioperative pain and fear were believed to be the causes. A temporary pacemaker was implanted to prevent sudden death due to vagal overstimulation.

Conclusion: Vagal reflex attenuation after pheochromocytoma resection can result in complete atrioventricular dissociation and sinus arrest. Adequate preoperative preparation and close monitoring during and after surgery are imperative.