[An elderly man with known heart failure admitted with cardiogenic shock]

A 75-year-old man with post-MI heart failure and an ejection fraction of 15 % was treated with an ACE-inhibitor, spironolactone and a beta-blocker. He had reduced his intake of food and water due to an intercurrent illness the days before admission. He was admitted to our coronary care unit due to bradycardia and hypotension. On arrival his blood pressure was 60/40 mm Hg, and he was in a cardiogenic shock. The electrocardiogram showed broad QRS-complexes and large T waves. Serum-potassium was 9.1 mmol/L and he had acute renal failure with oliguria, probably caused by reduced cardiac output due to hypovolemia combined with taking an ACE inhibitor and spironolactone. Haemodialysis was started and during dialysis QRS complexes became more narrow and heart rate and blood pressure normalized. The patient was discharged 10 days later with normal potassium and creatinine levels. Patients treated with ACE-inhibitors and spironolactone should be monitored closely. During intercurrent illness dehydration may occur and this can lead to renal failure and hyperkalemia which can be life-threatening. The condition should be recognized and addressed promptly, and if indicated haemodialysis should be performed.