IT IS WELL known that carotid sinus pressure in paroxysmal auricular tachycardia usually reverts the arrhythmia suddenly to normal sinus rhythm. Auricular flutter may be slightly and temporarily slowed by carotid sinus pressure, or there may be a sharp reduction in rate due to induced heart block. However, sinus rhythm is not thereby restored, as it is in auricular tachycardia. The production of regular sinus rhythm by carotid pressure during auricular flutter has not been reported, to our knowledge.
Chaotic heart rhythm results from the irregular disorderly discharges of numerous ectopic foci located in the auricles, the auriculoventricular node, and the ventricles. It is usually associated with advanced heart disease or digitalis intoxication. It is a serious prognostic sign and is often associated with sudden death. Physiologically, it represents a depression of the normal pacemakers of the heart and the dominance of various ectopic foci.1
The following case is