Atrial dissociation. A case of unilateral slow atrial rhythm.

Atrial dissociation is a very rare, transient arrhythmia frequently associated with intractable congestive heart failure. A case of atrial dissociation in a 48-year-old woman was observed in the first 72 hours of her recent inferolateral and probably atrial infarction. The slow unilateral rhythm was registered in the presence of sinus rhythm, 2:1 AV block, advanced AV block and ventricular pacemaker stimulation, respectively. The simultaneous right atrial electrogram indicated the origin of the isolated slow rhythm as left atrial. After temporary pacemaker therapy the atrial dissociation disappeared within three days; on the fifth day the normal sinus rhythm was restored spontaneously.