Relationship of atrial fibrillation to significant pericardial effusion in valve-replacement patients.

Rhythm change was observed in 21 of 242 (8.7%) patients during the first four weeks of open heart surgery (OHS). In the valve-replacement group of 148 patients the rhythm change was found to be associated with significant pericardial effusion (PE). Seven patients had rhythm changes during the first three days of OHS unrelated to PE. Two patients who were in atrial fibrillation (AF) developed fast ventricular rate and twelve patients showed rhythm change from sinus to supraventricular tachyarrhythmia (AF in ten and supraventricular tachycardia in two) and all these fourteen patients had significant PE. With pericardiocentesis or open drainage or withdrawal of anticoagulation, AF reverted to sinus rhythm in nine patients and five patients remained in AF but with a slow ventricular rate. Significant PE was related to a high anticoagulation ratio. We conclude from this study that within the first four weeks of OHS, high anticoagulation ratio contributes to the development of significant PE, and tachyarrhythmia (particularly AF) is a forerunner of significant PE or cardiac tamponade: the aim of management should be to rule out or show evidence of significant PE once tachyarrhythmia develops, and if significant PE is present then the pressure in the pericardial cavity should be reduced.