[Sinus node dysfunction in a "healthy heart" in an infant. A case report].

Sinus node dysfunction (SND) is a rare cause of bradycardia in children without structural heart disease. However the association between (SND) and abnormality of atrio-ventricular conduction, is more uncommon. We report a case of a child 23 months old, admitted in the cardiology department for a symptomatic bradycardia. Routine ECG and 24-h-Holter monitoring showed atrioventricular junctional rhythms with minimal rates of 24 bpm and episodes of asystole with a maximal duration of 3.7 seconds. The children was implanted with a permanent VVIR mode pacemaker to relieve his symptoms. During a follow-up period of four years, the child developed syncope, the epicardial pacing lead was broken and atrioventricular block was observed. A second pacemaker was inserted by a subclavicular vein, and was programmed in VVIR mode.