Transmembrane potentials and atrial fibrillation

¹ Department of Pharmacology, University of Mississippi School of Medicine, Jackson, Mississippi

The mean maximum following frequency of single atrial cells as determined by the microelectrode technique was found to be 820/min. with a range of 600–1050. The mean ‘firing’ rate of atrial cells during acetylcholine induced fibrillation was 900/min. with a range of 600–1250/min. The data are interpreted to mean that the observed changes in ion transport during fibrillation are not the result of higher firing rates of atrial cells as compared to those during rapid electrical excitation.