A 52-year-old woman, who had an out-of-hospital cardiac arrest, was resuscitated, intubated and transferred with cardiogenic shock to angioplasty of the right coronary artery. Afterwards the patient had normal biventricular function, but four days later she developed atrial fibrillation and recurrent cardiogenic shock with a left ventricular ejection fraction of 20%. Thyrotoxic crisis was determined as the underlying cause; and antithyroid treatment stabilised the patient's haemodynamics completely within 24 hours. The importance of high thyroxine levels in patients with ischaemic heart disease is discussed.
