Adenosine for the Management of Neonatal and Pediatric Supraventricular Tachycardia

Contributing Editor: Marcia L. Buck, Pharm.D.; Editorial Board: Kristi N. Hofer, Pharm.D.; Michelle W. McCarthy, Pharm.D.

Disclosures

Pediatr Pharm. 2008;14(8) 

In This Article

Use in Infants and Children

In 1987, Clarke and colleagues at Brompton and St. George's Hospitals in London published the first study of adenosine in pediatric patients.[5] They treated four children, three with paroxysmal SVT who were in cardiac failure, and one who was undergoing an elective EP study. They ranged in age from 7 days to 10 years. The patients were treated initially with an adenosine dose of 0.05 mg/kg given by IV and followed by a normal saline flush. If there was no response, the adenosine dose was increased by 0.05 mg/kg increments and repeated every 2 minutes until tachycardia was eliminated. Tachycardia resolved in all four children within 20 seconds. Three of the patients responded to a total dose of 0.1 mg/kg; the remaining patient required a dose of 0.25 mg/kg. Based on these initial cases, the authors concluded that adenosine may be a useful agent for termination of SVT in children and should undergo further study.

The following year, Overholt and colleagues at the University of Virginia published their experience with adenosine in 25 infants and children.[6] The patients ranged in age from 6 hours to 17 years. Eleven of the patients had sustained SVT, and 14 were undergoing an EP study. Adenosine was administered at an initial IV dose of 37.5 mcg/kg (0.0375 mg/kg). The dose was increased by 37.5 mcg/kg increments until a response was seen. Adenosine produced either termination of the arrhythmia or AV block in all patients. The average effective dose ranged from 114 to 165 mcg/kg (approximately 0.1 to 0.2 mg/kg), depending on the underlying arrhythmia. Six patients (24%) had minor adverse effects. One patient had bradycardia requiring temporary pacing. As in the Clarke study, the authors concluded that adenosine was a safe and effective agent for the evaluation and treatment of SVT in children.

In 1989, Till and colleagues from London, the same investigators from the 1987 study, published the largest pediatric adenosine series to date.[10] They reviewed 117 episodes of SVT in 50 children ranging in age from 1 day to 17 years. Adenosine was administered at an initial IV dose of 0.05 mg/kg, with subsequent doses increased by 0.05 mg/kg increments every 2 minutes until the arrhythmia was controlled or a maximum single dose of 0.25 mg/kg was reached. Adenosine was successful in terminating 90 (77%) of the 117 episodes. The median effective dose was 0.15 mg/kg, with a range of 0.05 to 0.25 mg/kg.

The most common adverse effects reported after adenosine administration in this patient series were flushing and transient changes in respiration. One child developed nausea and a headache. One infant experienced a period of sinus bradycardia lasting less than 40 seconds. Two patients developed transient heart block, resolving in less than 10 seconds. One child developed a transient junctional rhythm and six had ventricular couplets or extrasystoles immediately after adenosine administration. Re-emergence of SVT occurred in 13 of the successfully treated patients. Based on the results of this study, as well as their earlier work, the authors concluded that adenosine was an effective treatment for SVT in infants and children, as well as a useful diagnostic tool.[10]

In 1994, Ralston and colleagues reviewed their experiences with adenosine in 24 children with narrow-complex tachycardias.[11] The median age of the patients was 4 years. Four patients were neonates. The initial dose of adenosine was 0.1 mg/kg; this was doubled (up to 12 mg) and repeated if there was no response within 5 minutes. Adenosine produced AV block in 21 (88%) of the patients. The patients who failed to respond included two cases of atrial flutter and one patient with ectopic atrial tachycardia. Complete termination of tachycardia was achieved in 11 of the 21 patients who responded. In 17 cases, adenosine was useful in determining the underlying cause of the tachycardia.

Sherwood, Lau, and Sholler published an additional retrospective review in 1998.[12] They described the use of adenosine in 43 children with SVT. The median patient age was 1 year, with a range from 1 day to 16 years. Conversion to normal sinus rhythm occurred in 75% of the patients, including 96% of the children with re-entrant SVT. In a quarter of the patients, their arrhythmia resumed after the dose had been cleared. Sixteen percent of the patients responded to an initial dose of 0.05 mg/kg. Another 35% responded to a dose of 0.1 mg/kg, Adenosine was well tolerated. Six patients experienced transient bradycardia. Transient sinus arrest, Wenckebach phenomenon, and complete AV block were reported immediately after adenosine administration, but resolved without treatment. Fifteen patients had other transient adverse effects, most often facial flushing. Children old enough to respond to questions regarding adverse effects frequently described chest discomfort, and less commonly, light-headedness, abdominal pain, tiredness, nausea, and arm discomfort at the injection site. None of the patients discontinued treatment because of adverse effects.

The cumulative results of these case series and retrospective studies have established the efficacy of adenosine in the treatment of SVT in infants and children. Adenosine is typically not effective in converting atrial flutter or fibrillation, although it may slow ventricular response to atrial arrhythmias. It is not effective in the treatment of most ventricular arrhythmias, however there are reports of adenosine-sensitive ventricular tachycardias arising from the right ventricular outflow tract.[13] There are also reports of its use in the management of junctional tachycardia occurring after surgery to correct congenital heart disease, although it is not considered routine therapy for any arrhythmias other than SVT.[14]

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