Perinatal atrial flutter: different therapeutic outcomes in two case reports.

Atrial flutter is a rare but potentially lethal arrhythmia, characterized by a rapid regular atrial rate, accompanied by variable degrees of atrioventricular block. Two cases of neonatal atrial flutter are described. The first case was diagnosed in utero at 38 weeks of gestation and converted to sinus rhythm by electric shock on the eighth day of life. Case two, diagnosed at 11 days old, with a background of acute bronchiolitis and tachycardia associated with a cardiac tumor, was refractory to electrical cardioversion. Both cases proved difficult to convert to sinus rhythm, but there was clinical improvement and no recurrence. These two cases exemplify the variability of outcomes achieved with anti-arrhythmic agents and direct current cardioversion.