Procainamide for rate control of postsurgical junctional tachycardia

This study was conducted to determine the efficacy of procainamide therapy for rapid rate control of postoperative junctional tachycardia (JT). Postop erative JT is one of the most difficult forms of tachycardia to manage. Rep orted success with a variety of treatments of JT in infants and children ha s been inconsistent and limited. Rate control using procainamide was achiev ed in 17 children having rapid JT (heart rate >200 beats/min) between 1986 and 1997. In the first 5 patients (protocol A), following a loading dose of 3 mg/kg over 20 minutes, a continuous procainamide infusion was initiated at a rate of 20 mu g/kg/min. The infusion dose was increased in 10 mu g/kg steps every 30 minutes to 40-120 mu g/kg/min until the heart rate decreased below the target rate of 180 beats/min. In the other 12 patients (protocol B), after a higher loading dose of 10 mg/kg the infusion rate was increase d every 10-15 minutes until the heart rate decreased below the target rate of 180 beats/min. Procainamide decreased JT rates in all patients but the r esponse was significantly faster in protocol B. In the patients treated wit h protocol A, pretreatment JT rates ranged from 203 to 240 (213 +/- 17) bea ts/min and decreased to 195 +/- 10 beats/min at 2 hours (p, = ns), 186 +/- 8.8 at 4 hours (p < 0.02), and 179 +/- 8 at 6 hour postinitiation of PA. In protocol B, pretreatment JT rates ranged from 201 to 240 (218 +/- 17) beat s/min and decreased to 183 +/- 20 beats/min at 2 hours (p < 0.001) and 171 +/- 12 at 4 hours after starting the procainamide therapy. The mean duratio n to decrease JT rates below the target rate of 180 beats/min was 3.2 +/- 1 .1 hours in protocol B compared to 6.4 +/- 3.8 hours in protocol A (p < 0.0 2). Eight of 12 patients in protocol B achieved rate control below the targ et rate of 180 beats/min within 4 hours despite remaining on significant in otropic support. The procainamide infusion rates to maintain heart rates be low 180 beats/min were 40-120 (68.4 a 22.1) mu g/kg/min. No proarrhythmia, bradycardia, or significant hypotension was observed. In this series procai namide provided safe, effective, and rapid rate control of JT occurring in the immediate postoperative period.