Fever and Cardiac Rhythm

Abstract

• To study the effect of fever on cardiac rhythm and conduction, we recorded 24-hour electrocardiograms in 27 young men during an uncomplicated acute febrile infection (12 patients had adenovirus, four had influenza, three had Mycoplasma pneumoniae, and eight were undefined) and after recovery. During the first 24-hour recording period, the mean axillary temperature in the whole group was 38.4 °C. The mean heart rate during the febrile period was 84.0 beats per minute. After recovery, it was 66.5 beats per minute. When the temperature rose by 1 °C, the heart rate increased on the average by 8.5 beats per minute. During the febrile period, the heart rate remained high, even during sleep. The PR interval shortened significantly at a heart rate of 60 beats per minute and occasional first- or second-degree atrioventricular blocks were rarer. The QT interval shortened significantly at heart rates of 60, 80, and 100 beats