[Congenital sick sinus syndrome in a healthy heart: case report].

Isolated congenital sick sinusal syndrome on non harmed heart is a rare affection. Its association with an atrio-ventricular block is exceptional. The authors report a case of a 19 year-old patient, with an early history of bradycardia, hospitalised for effort intolerance. His electrocardiogram reveals a high degree sino-atrial block replaced by a junctional rhythm at 30/mn. During Treadmill test, the sinusal acceleration is satisfactory and an effort atrio-ventricular block was present. He later had a definitive stimulation under DDDR. This report shows that the sinusal node, in the same way as the atrio-ventricular node may be injured by congenital dysimmunitary process. The coexistence of these two conductive troubles worsen the prognosis and should lead more often to the practice of definitive stimulation by the only mode DDDR.