Adverse effects of febrile state on cardiac performance.

The hemodynamic characteristics of 36 febrile patients were studied when temperature was greater than 100 degrees F and after resolution of fever (temperature less than or equal to 100 degrees F). The patients were divided into those with bacterial infection (group I, n = 26) and those whose fever was noninfectious in etiology (group II, n = 10). Analysis of patients likely to have coronary artery disease (CAD) (subset A, n = 12) and those unlikely to have CAD (subset B, n = 7) was carried out. To maintain constant preload, pulmonary artery wedge pressure varied by not more than 2 mm Hg in all patients. Resolution of fever was associated with a 23% increase in stroke volume index (SVI) and 37% increase in left ventricular stroke work index (LVSWI) for group I (p less than 0.01). Group II showed a 27% increase in SVI and a 38% increase in LVSWI (p less than 0.05). Both subsets A and B showed significant increases in LVSWI after resolution of fever. We found evidence of decreased left ventricular performance during the febrile state in patients with and without infections. Since all groups and subsets maintained a normal or high cardiac index associated with increased heart rate during the febrile state, the tachycardic response of the febrile patient may serve to maintain cardiac output when myocardial performance is impaired.