Radiofrequency Ablation of Accessory Pathways
Radiofrequency ablation is a nonsurgical approach designed to
eliminate atrial or ventricular re-entrant tachyarrhythmias. The technique requires
pathway mapping and precision ablation of the aberrant pathway, using a radiofrequency
ablation catheter. During the
ablation, unexpected patient movement may result in catheter dislodgment and damage
to normal conducting tissue; therefore, general anesthesia is usually required in
younger children. Anesthetic agents and techniques should be chosen to maintain
circulating catecholamines and avoid suppression of arrhythmogenesis, for identification
of the aberrant pathway. Our current preference is a propofol continuous intravenous
anesthetic, although low-dose volatile anesthetics are equally satisfactory. Rapid
atrial pacing and, occasionally, an isoproterenol infusion are required during the
mapping procedure.
Severe post-procedural cardiomyopathy has been described but is
very unusual. An underlying cardiomyopathy from frequent episodes of supraventricular
tachycardia and myocardial oxygen imbalance caused by prolonged periods of rapid
atrial pacing and isoproterenol infusions are the presumed causative factors. An
arterial line is helpful during these lengthy procedures for continuous monitoring
of blood pressure and blood gases.
