[Idiopathic dilatation of the heart atrium with complete auricular paralysis]. / Dilatation idiopathique des oreillettes avec paralysie auriculaire complète.

The authors report the case of a patient with idiopathic dilatation of the auricles and complete atrial paralysis associated with absence of excitability of the atrial muscle. Repeated echocardiograms over a period of three months demonstrated dilatation of the auricles and ventricles with the development of mitral and tricuspid incompetence. The role played by the junctional bradycardia in the ventricular dilatation is discussed and the patient was explored haemodynamically with varying rates of ventricular pacing. In view of the improvement in the haemodynamic parameters, a cardiac pacemaker was inserted. After a follow-up of one year, the ventricular chambers have returned to normal and the mitral and tricuspid incompetence has regressed, while the atrial muscle continues to dilate. The patient is currently asymptomatic with no medical treatment.

[Idiopathic dilatation of the right atrium in 2 infants disclosed by arrhythmia]. / Dilatation idiopathique de l'oreillette droite révélée chez deux nourrissons par des troubles du rythme.

Idiopathic right atrial dilatation is a rare and probably congenital malformation. Two new cases are reported, in an 18 months old infant and a six week old baby, both presenting with supraventricular tachyarrhythmias. Clinical examination was normal. Chest X-ray showed bulging of the right heart border and electrocardiography revealed partial right bundle branch block. The diagnosis was made by echocardiography which showed aneurysmal dilatation of the right atrium. There were no signs of valvular heart disease or of an intracardiac shunt; the septal tricuspid leaflet was in its normal position. M-mode recordings showed no signs of Ebstein's anomaly. The diagnosis was confirmed by cardiac catheterisation in the first case; this investigation seemed to be pointless in the second case. Both children experienced many episodes of supraventricular tachyarrhythmias. The first developed tricuspid regurgitation but the second remains asymptomatic.