['Blood lactate is an accurate predictor of outcome in clinical shock syndrome patients. However, its usefulness in status I heart transplant candidates with failing myocardium is largely unknown. The purpose of this study was to determine whether serum lactate levels are predictive of congestive heart failure severity in cardiomyopathic status I cardiac transplant candidates.', 'Over a 6-month period, serial arterial serum lactate levels in 30 status I heart transplant candidates were measured. Measured serum lactate values (mmol/L) included the initial lactate level upon admission to the intensive care unit and the lactate level at 6-week intervals up to 24-weeks. Surveillance right heart catheterizations were also performed at 6-week intervals to determine pulmonary artery pressures and cardiac index. Baseline measurements were compared with the values obtained at time intervals of 6-, 12-, 18-, and 24-weeks.', "All status I heart transplant candidates were admitted to the intensive care unit for treatment of worsening heart failure with intravenous inotropic therapy. All patients had severe pulmonary hypertension (greater than two-thirds of systemic arterial pressure, mmHg) and/or severe low cardiac output state (cardiac index less than 2.0 L/min/M(2)). Admission lactate level was normal in all candidates. Intravenous inotropic therapy improved patients' symptoms and cardiopulmonary hemodynamic derangements although lactate levels remained within the normal range until the time of heart transplant operation or up to 24-weeks (p=NS)."] Are serum lactates predictive of heart failure severity in status I cardiac transplant candidates?