Atrial tachycardia from enhanced automaticity in children: diagnosis and initial management.

Ten patients (aged 0-9 years) with the diagnosis of automatic atrial tachycardia (AAT) from August 1997 to August 2000 were reviewed. Three patients had paroxysmal (repetitive) AAT and the tachycardia was incessant in six (defined as presence of AAT for more than 90% of the time). The type of AAT in one patient was unknown. Four patients presented with congestive heart failure (CHF), one with pre-syncope, one with palpitation, and four were asymptomatic. Six patients (60%) had depressed left ventricular ejection fraction. All patients with CHF had incessant AAT with atrial rate > 220/min and ventricular rate > 200/min at admission. After treatment with antiarrhythmic medications, all patients had adequate control of the AAT (9 had complete elimination of AAT and 1 partial control). Amiodarone (alone, or in combination with digoxin) was effective in 5 of 6 cases (83%), although complete elimination of the AAT was usually delayed (median = 5 days, range 30 minutes to 17 days). Other effective medications were digoxin, digoxin + propranolol and atenolol (all in patients who did not have CHF on presentation). At the time of this report, 3 patients had no AAT off antiarrhythmic medication, 5 patients were still receiving treatment (with good control) and 2 patients died from sepsis during the same admission even though AAT was controlled. All surviving patients had normal ventricular ejection fraction on follow-up. AAT in children is rare, but when it occurs in persistent form at a fast rate, it is usually associated with CHF and is difficult to treat. Amiodarone (+/- digoxin) effectively controls the arrhythmia in the majority of cases, although full effect may take several days. With successful treatment, most patients do well and some can be taken off the medication(s) without recurrence of the arrhythmia.