Changes of myocardial enzyme activities in atrial fibrillation.

Cholinesterase and succinyldehydrogenase activity of surgically removed left atrial auricles from patients in atrial fibrillation and in sinus rhythm have been compared, using histochemical methods. Higher cholinesterase and lower succinyldehydrogenase activity has been found in atrial fibrillation than in sinus rhythm. The pulmonary capillary mean pressure of patients with atrial fibrillation and sinus rhythm have been also compared. There was no significant difference between the two groups. On the basis of the reported examinations, it is not possible to decide whether the changes in enzyme activities are the cause or the result of atrial fibrillation.