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To define the mechanisms of unexpected cardiac arrest in advanced heart failure, we reviewed the causes of cardiac arrest as established from electrocardiographic monitoring and from clinical and autopsy data in patients hospitalized for cardiac transplantation evaluation and management of advanced heart failure (mean left ventricular ejection fraction, 0.18 +/- 0.08) who were stable while on vasodilator and diuretic therapy such that hospital discharge to home was anticipated. Twenty-one cardiac arrests occurred in 20 of 216 (9%) such patients during a 4-year period. Heart failure was due to coronary artery disease with prior myocardial infarction in 13 patients and nonischemic cardiomyopathy in seven patients. The rhythm at the time of arrest was severe bradycardia or electromechanical dissociation (BA/EMD) in 13 (62%) patients. The precipitating cause of the BA/EMD arrest was coronary artery thrombosis or embolism in two patients, pulmonary embolism in one patient, hyperkalemia in two patients, and unexplained hypoglycemia in one patient. In seven of 13 (54%) patients, a precipitating cause of the bradycardia arrest could not be established. Only eight of 21 (38%) arrests were due to ventricular tachycardia or fibrillation (VT/VF), and all occurred in patients with prior myocardial infarction (p = 0.02 vs. BA/EMD arrests). Two VT/VF arrests were due to acute or recent infarction, and one patient had hyperkalemia. The patients who suffered a BA/EMD arrest were similar to those who had a VT/VF arrest in age, ventricular arrhythmia history, ventricular function, and serum potassium levels. Serum sodium levels were lower in patients with BA/EMD arrests (129 +/- 3 vs. 133 +/- 4 meq/l, p = 0.025).(ABSTRACT TRUNCATED AT 250 WORDS)

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To determine the prevalence and significance of abnormal thyroid hormone metabolism in congestive heart failure, free thyroxine (T4) index, free triiodothyronine (T3) index, reverse T3 and thyrotropin levels were obtained in 84 hospitalized patients with chronic advanced heart failure. Free T4 index was normal in all patients. Free T3 index was reduced or reverse T3 elevated, or both, leading to a low free T3 index/reverse T3 ratio in 49 (58%) of the 84 patients. A low free T3 index/reverse T3 ratio was associated with higher right atrial, pulmonary artery and pulmonary capillary wedge pressures and lower ejection fraction, cardiac index, serum sodium, albumin and total lymphocyte count. In multivariate analysis, the free T3 index/reverse T3 ratio was the only independent predictor of poor 6 week outcome (p less than 0.001); the actuarial 1 year survival rate was 100% for patients with a normal ratio and only 37% for those with a low ratio (p less than 0.0001). A low free T3 index/reverse T3 ratio is associated with poor ventricular function and nutritional status and is the strongest predictor yet identified for short-term outcome in patients with advanced heart failure.

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