Optimal dose of adenosine effective for supraventricular tachycardia in children

To determine the optimal adenosine dose effective in supraventricular tachycardia (SVT) and underlying conditions affecting the effective dose in children. Experimental study. Department of Cardiology, The Children's Hospital and Institute of Child Health, Lahore, from July 2008 to June 2011. All children presenting with SVT were administered adenosine in rapid boluses according to PALS guidelines using incremental doses of 100, 200 and 300 μg/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. 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 μg/kg was only effective in 36.4% episodes of SVT. Two hundred μg/kg was effective in 44.3% of those not responding to 100 μg/kg dose (n = 31/70, cumulative 64.5%). A dose of 300 μg/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 μg/kg with median effective dose of 200 μg/kg. Significantly higher dose of adenosine was required in children with underlying pre-excitation, n = 18/97 (220.8 + 67.6 μg/kg vs. 177.2 + 81.9 μg/kg, p = 0.039). Adenosine is an effective medicine in treating SVT in children. A higher dose of 200 μg/kg may be used as first bolus particularly in children with pre-excitation.