Chaotic atrial rhythm in children.

Chaotic atrial rhythm (CAR) usually occurs as a sequela of chronic obstructive lung disease in adults. We report the clinical manifestations and response to therapy in nine children with CAR treated predominantly with propafenone or amiodarone. Age at presentation ranged from 1 day to 30 months; six patients were < or = 2 weeks old. Six patients had tachycardia, and three had congestive heart failure. The atrial rate was 200 to 500 (mean 369 +/- 71) beats/min and the ventricular rate 150 to 300 (mean 251 +/- 37) beats/min. Eight patients had cardiac abnormalities. Intravenous drug therapy was not successful in converting CAR to sinus rhythm in any patient. A mean of four (range three to five) drugs was used in each patient; amiodarone and propafenone, alone or in combination, proved most successful. Seven patients were discharged from the hospital: full control was achieved in three (digoxin and amiodarone in two and digoxin, amiodarone, and procainamide in one), good control in three (digoxin, amiodarone, and propafenone in two and digoxin and propafenone in one), and ventricular rate control in one (digoxin, amiodarone, and propafenone). Two neonates with hypertrophic cardiomyopathy died. Long-term follow-up showed that CAR had resolved in five patients but persisted in two. We conclude that CAR remains difficult to control despite the use of newer antiarrhythmic agents but may resolve during long-term follow-up.