Should an abnormal serum potassium concentration be considered a correctable cause of cardiac arrest?

According to American Heart Association/American College of Cardiology Prac tice Guidelines, electrolyte abnormalities, including abnormal serum potass ium concentrations, are considered a correctable cause of a life-threatenin g ventricular arrhythmia. Ventricular defibrillator therapy in this situati on is a class III indication, and thought to be ineffective and perhaps har mful, although there are minimal data to support this recommendation. The s teady-state serum potassium concentration frequently changes during a cardi ac arrest. Additionally, the vast majority of cardiac arrest patients have structural heart disease and are commonly treated with a variety of medicat ions that can alter the serum potassium concentration. In the Antiarrhythmi cs Versus Implantable Defibrillators (AVID) trial, patients with a correcta ble cause of an electrolyte imbalance were excluded from study participatio n but were followed in the AVID registry. Similar outcomes were observed am ong patients in the AVID registry and the main trial. Spironolactone therap y in patients with congestive heart failure decreases all-cause mortality a nd sudden and nonsudden cardiac death. In a preliminary study of 169 patien ts with an episode of a sustained ventricular arrhythmia treated with an im plantable defibrillator, freedom from appropriate defibrillator therapy was 18% after five years. The probability of appropriate defibrillator therapy was independent of the initial serum potassium concentration. For these re asons, our current clinical practice is to use an implantable defibrillator to treat an initial episode of sustained ventricular tachycardia or ventri cular fibrillation that occurs in a patient with structural heart disease a nd an abnormal serum potassium concentration. (C) 2001 by the American Coll ege:of Cardiology.