Flail tricuspid leaflet in childhood--a possible cause of supraventricular tachycardia.

The echocardiographic features of flail tricuspid leaflet of unknown aetiology is reported. The diagnosis was made in a previously healthy 11 year old boy presenting with recurrent attacks of supraventricular tachycardia. M-mode echocardiography showed rapid early systolic movement of the tricuspid valve away from the transducer and holosystolic, coarse fluttering of its small, redundant part. The sector scan, showing the free movement of a part of the septal tricuspid leaflet into the right atrium during systole was confirmatory. It was felt that Ebsteins anomaly could be excluded. The recurrent attacks of supraventricular tachycardia were difficult to treat pharmacologically, and may have been related to the flail tricuspid leaflet which mechanically triggered the arrhythmia through an aberrant pathway.