Objectives: Supraventricular tachycardia is the most common arrhythmia in infants, and antiarrhythmic medications are frequently used for prophylaxis. The optimal prophylactic antiarrhythmic medication is unknown, and prior randomized trials have been underpowered. We used data from a large clinical registry to compare efficacy and safety of digoxin and propranolol for infant supraventricular tachycardia prophylaxis. We hypothesized that supraventricular tachycardia recurrence is less common on digoxin when compared with propranolol.
Design: Retrospective cohort study.
Setting: Pediatrix Medical Group neonatal ICUs.
Patients: Infants discharged from 1998 to 2012 with supraventricular tachycardia who were treated with digoxin or propranolol. We excluded infants discharged before completing 2 days of therapy, those with Wolff-Parkinson-White syndrome, structural heart defects (except atrial/ventricular septal defects and patent ductus arteriosus), and those started on multidrug therapy.
Measurements and main results: We used Cox proportional hazards to evaluate supraventricular tachycardia recurrence, defined as need for adenosine or electrical cardioversion while exposed to digoxin versus propranolol, controlling for infant characteristics, inotropic support, supplemental oxygen, and presence of a central line. We identified 342 infants exposed to digoxin and 142 infants exposed to propranolol. The incidence rate of treatment failure was 6.7/1,000 infant-days of exposure to digoxin and 15.4/1,000 infant-days of exposure to propranolol. On multivariable analysis, treatment failure was higher on propranolol when compared with that on digoxin (hazard ratio, 1.97; 95% CI, 1.05-3.71). Hypotension was more frequent during exposure to digoxin versus propranolol (39.4 vs 11.1/1,000 infant-days; p < 0.001). There was no difference in frequency of other clinical adverse events.
Conclusions: Digoxin was associated with fewer episodes of supraventricular tachycardia recurrence but more frequent hypotension in hospitalized infants relative to propranolol.