Optimal Dose of Adenosine Effective for Supraventricular Tachycardia in Children

Objective: To determine the optimal adenosine dose effective in supraventricular tachycardia (SVT) and underlying conditions affecting the effective dose in children. Study Design: Experimental study. Place and Duration of Study: Department of Cardiology, The Children's Hospital and Institute of Child Health, Lahore, from July 2008 to June 2011. Methodology: All children presenting with SVT were administered adenosine in rapid boluses according to PALS guidelines using incremental doses of 100, 200 and 300 mu g/kg. The response was recorded on 12 lead ECG. Preexcitation was documented and echocardiography performed on all children after attaining sinus rhythm. Mann Whitney test and Kruskal-Wallis test were used as a test of significance to determine any difference in effective adenosine dose between normal heart and various underlying conditions, taking p < 0.05 as significant. Results: Eighty five patients were treated for 110 episodes of SVT with adenosine. M:F ratio was 2.2:1. Their age ranged from 6 days to 14 years with mean age of 27.9 months. Adenosine was effective in reverting 97 episodes of SVT to sinus rhythm (88.2%). A dose of upto 100 mu g/kg was only effective in 36.4% episodes of SVT. Two hundred mu g/kg was effective in 44.3% of those not responding to 100 mu g/kg dose (n = 31/70, cumulative 64.5%). A dose of 300 mu g/kg was effective in further 25 patients not responding to lower doses (n = 25/38, 65.8%; cumulative 88.2%). Mean effective dose of adenosine was 185.3 +/- 81.0 mu g/kg with median effective dose of 200 mu g/kg. Significantly higher dose of adenosine was required in children with underlying pre-excitation, n = 18/97 (220.8 +/- 67.6 mu g/kg vs. 177.2 +/- 81.9 mu g/kg, p = 0.039). Conclusion: Adenosine is an effective medicine in treating SVT in children. A higher dose of 200 mu g/kg may be used as first bolus particularly in children with pre-excitation.