PHARMACOLOGICAL MANAGEMENT OF SUPRAVENTRICULAR TACHYCARDIAS IN CHILDREN .2. ATRIAL-FLUTTER, ATRIAL-FIBRILLATION, AND JUNCTIONAL AND ATRIAL ECTOPIC TACHYCARDIA

OBJECTIVE: To review the literature regarding the use of antiarrhythmi c agents in the management of atrial flutter (AF), atrial fibrillation (Afib), junctional ectopic tachycardia (JET), and atrial ectopic tach ycardia (AET) in infants and children. To discuss the advantages and d isadvantages of specific agents in each type of arrhythmia in an effor t to develop treatment guidelines. DATA SOURCES: A MEDLINE search enco mpassing the years 1966-1996 was used to identify pertinent literature for discussion, Additional references were found in the articles, whi ch were retrieved via MEDLINE. STUDY SELECTION: Clinical trials that a ddress the use of antiarrhythmic agents for the treatment of supravent ricular tachycardia, AF, Afib, JET, and AET in children were selected. Literature pertaining to dosage, pharmacokinetics, efficacy, and toxi city of antiarrhythmic agents in children were considered for possible inclusion in the review; information judged to be pertinent by the au thors was included in the discussion. DATA EXTRACTION: Although there are numerous reports of antiarrhythmic use in children, there are very few large studies designed that evaluate the use of specific antiarrh ythmic agents in the treatment of AF, Afib, JET, or AET. Ideally, cont rolled clinical trials are used to develop clinical guidelines; howeve r, in this situation, most data and information must be obtained from case series of children treated. Although the results from these types of studies may be useful in developing guidelines for the optimal use of these agents for the treatment of AF, Afib, JET, and AET, controll ed trials are required for establishing standard treatment guidelines for all patients. DATA SYNTHESIS: Despite limited scientific evaluatio n of conventional agents in the treatment of AF, Afib, JET, or AET in children: they continue to be the standards of care. Most information regarding the use of conventional agents in children has been extrapol ated from the adult literature. Little justification for the use of th e agents or dosing in children is available. Controlled trials regardi ng the use of newer antiarrhythmic agents (propafenone, amiodarone, fl ecainide) are available; however, the variance in dosing schemes, pres ence of structural heart disease, and patient age may confound the res ults. CONCLUSIONS: Because of greater clinical experience, conventiona l antiarrhythmic agents generally remain as first-line therapy in the management of most supraventricular tachycardias in children. Atrial p acing or cardioversion to reestablish sinus rhythm is indicated for in itial episodes of AF in infants, followed by chronic prophylactic ther apy in those with significant structural heart disease or in infants i n whom AF recurs. Attempts to eliminate AF in children outside the neo natal or infancy period should begin with trials of traditional agents such as digoxin or procainamide, and if unsuccessful, subsequent tria ls of amiodarone. Digoxin and beta-blockers remain the mainstay of the rapy for children with Afib, followed by procainamide for treatment fa ilures. Intravenous amiodarone, the newest addition to our antiarrhyth mic armamentarium, is the most promising agent in the treatment of pos toperative JET. This arrhythmia has been traditionally managed with co rporal cooling and/or digoxin therapy; however, intravenous amiodarone may now be a valuable option. Although relatively unsuccessful in the management of congenital JET and AET, conventional agents are typical ly used prior to the initiation of long-term therapy with potentially more toxic agents such as amiodarone or propafenone. Additional well-d esigned, controlled trials are needed to further evaluate the comparat ive efficacy of agents such as flecainide, sotalol, moricizine, propaf enone, and amiodarone in the management of AF, Afib, JET, and AET in c hildren, as well as to evaluate the dosing and toxicity in various age groups.