A retired civil servant, 76 years of age, was admitted to a psychiatric older adults ward because of his dementia. Two months previously he had suffered a cardiac arrest in the street and received cardiopulmonary resuscitation from a bystander for approximately 10 minutes. Paramedics who attended identified ventricular fibrillation and used a defibrillator to restore cardiac output. On arrival at the local accident and emergency department he was defibrillated again, intubated and sedated. Once stabilized on an intensive care unit he was transferred to a cardiology unit. In his early sixties the patient had suffered a myocardial infarction and developed mitral valve dysfunction and chronic atrial fibrillation. He received a prosthetic mitral valve (St Jude valve), underwent coronary artery bypass grafting and was commenced on digoxin. Following the cardiac arrest he underwent angioplasty and insertion of a drug-eluting Taxus stent into the right coronary artery. An implantable cardioverter defibrillator was then implanted. At the time of these procedures the patient was noted to have marked cognitive impairment, assumed to be secondary to hypoxic brain injury. Magnetic resonance imaging showed mild cerebral and left cerebellar changes suggestive of ischaemia. There was a small but old haemorrhagic focus in the left frontal lobe. Increased support in self-care at home was arranged and he was discharged on digoxin, furosemide, perindopril, pravastatin, clopidogrel, tamsulosin, finasteride, omeprazole and warfarin. Two weeks following this discharge his wife noted agitated behaviour and personality change. Their GP referred him to local mental health services and concerns about this level of agitation prompted the psychiatric admission. On admission to the psychiatric ward the patient denied any past psychiatric history but acknowledged that he had always been absent-minded. He admitted to drinking half a bottle of wine a week but denied use of illicit drugs. His wife added that his mother had been diagnosed with schizophrenia in later life and had died at 65 years of age. She corroborated that his memory difficulties had predated his recent medical admission and had involved leaving the phone off the hook, unsafe use of the gas cooker, and difficulties finding possessions. Since the medical discharge his mood had become labile, marked by considerable anhedonia and episodes of tearfulness. On mental state examination there was no evidence of any affective or psychotic symptoms, but pressure of speech and circumstantiality were noted. There was evidence of some persecutory beliefs regarding his wife and her attempts to contain him at home, but these were largely founded on reality. Cognitive testing revealed reduced 5-minute recall but no signs of occipital or parietal lobe dysfunction. Physical examination was unremarkable. Routine investigations were requested and he was commenced on amisulpride 50 mg at night in addition to his regular medications. On the evening of admission nursing staff called the duty psychiatrist to the ward as the patient was mildly agitated, refusing his night-time medications. The doctor talked to him about the importance of his cardiac medications, and the patient became more agitated, displaying evidence of disorientation, confabulation and a lack of insight. Oral lorazepam was offered to reduce his agitation but he refused this. Believing that clinical notes were being inaccurately recorded he seized the history sheet and crumpled it in his pocket. At this point at least four nursing staff and the on-call doctor were joined by a member of security staff, resenting an environment potentially perceived to be threatening. The security guard reached into the patient's pocket to retrieve the clinical notes, and the patient's implantable cardioverter defibrillator activated, giving both an electric shock. The implantable cardioverter defibrillator activated a further three times. At this point a decision was made to reduce the number of staff present and to clear some space around the patient. Tranquillization was indicated both for the patient's level of agitation and to allow assessment of any cardiovascular compromise. However, he refused oral lorazepam, and parenteral administration risked further dysrhythmias. Disarmed of pharmacological options the only viable strategy was to request one-to-one nursing in a quiet area and to use verbal de-escalation techniques. The patient maintained an animated discussion with his nurse throughout the night but experienced no further shocks from his implantable cardioverter defibrillator. During his 5-week admission improvements were noted in his cognitive function, amisulpride was increased to 150 mg daily, and he became more settled. Outpatient review of his implantable cardioverter defibrillator revealed no abnormalities. He was discharged home with input from care workers, community psychiatric nurses and weekly day hospital placement. Almost a year on he remembers nothing of these events and reports feeling well despite some short-term memory difficulties. He is functioning well at home and his wife reports a general improvement in his mental functioning.