ABSTRACT
This disturbance is a form of severe atrial ectopic behaviour in which, in addition to impulses from the SA node, there are many others that originate from various foci in the atrium. As a result, there is a variation in rhythm, a changing P wave shape, and a changing PR interval. The abnormalities sometimes occur in runs and a rhythm strip may be required for the presence of other pacemakers to be seen. The QRS is usually normal (apart from rare aberrant conduction). This arrhythmia may occur in normal individuals, but is also not uncommon after myocardial infarction or digitalis therapy, and during myocarditis (especially rheumatic fever), in which case the real anaesthetic risks are those of the underlying condition.
