Introduction: Baroreceptor damage and hypersensitivity can produce labile autonomic blood pressure control. Neck irradiation for malignancy is a well-known but under-recognised cause of baroreceptor failure. Case presentation: We describe a dramatic delayed complication of neck irradiation treatment. Our patient developed recurrent unexplained hypotension and pulseless electrical activity cardiac arrest upon connection to intermittent haemodialysis, which he had previously tolerated uneventfully until exposure to radiotherapy. Conclusion: No other cause was identified, and this case thus highlights baroreflex dysfunction as an important differential diagnosis in patients with profound hypotension.