ATRIAL FLUTTER IN INFANCY: NO NEED FOR CHRONIC PROPHYLAXIS

Abstract

Many authorities recommend digoxin for one year for atrial flutter (AT.FL) in infants with normal structural hearts. To re-examine this recommendation the electrocardiogram, response to programmed extrastimulation, (PES) (n=3), and clinical course in six infants with AT.FL. alone were reviewed. AT.FL exhibited a regular sawtooth pattern with a cycle length of 148 msec (range: 130-160 msec). Age at diagnosis was 34 days (range: birth (n=4) to 180 days). There were two males and four females; all were initiallly treated with digoxin but only two converted to sinus rhythm. AT.FL resolved spontaneously in two, two were converted with atrial overdrive pacing. Post-conversion electrocardiogram demonstrated normal P wave axis, PR interval .14 sec (range: .12-.16 sec), P wave duration .08 sec, and P wave amplitude .23 mV (3 > .25 mV) at heart rate 142 bpm. Post-conversion atrial PES with burst pacing in three failed to initiate AT.FL and demonstrated normal atrial effective refractory periods (158 msec; range: 150-173 msec) and normal atrioventricular conduction system effective refractory periods (199 msec; range: 180-216 msec). Only two patients were maintained on digoxin, six months and one year after conversion. Follow-up was 5.5 years (1.5 - 18 years) without recurrence. These data suggest that AT.FL in infants without structural heart disease, following conversion, is self-limited and not easily inducible by extrastimulation. We conclude that infants with atrial flutter alone, following cardioversion, do not require chronic prophylaxis.