Introduction: There has been limited experience with radiofrequency catheter ablation in patients with dextrocardia. This report describes a 37-year-old man who had secundum type atrial septal defect, mirror-image dextrocardia, and drug-refractory atrial tachycardia, in whom catheter-mediated radiofrequency energy successfully eliminated the tachycardia without complication.
Methods and results: On electrophysiologic study, the atrial tachycardia could be induced and terminated by atrial extrastimulation or rapid atrial pacing. Mixed resetting response pattern and manifest entrainment were also demonstrated. These findings suggested that the mechanism of atrial tachycardia might be related to reentry with an excitable gap. Because of the mirror-image dextrocardia, biplane fluoroscopy was adjusted to the right anterior oblique (RAO) 60 degrees and left anterior oblique (LAO) 30 degrees positions. Inducibility of the tachycardia was completely abolished after the sixth application of radiofrequency current (30 W). It was noted that the successful electrogram preceded the onset of P wave during atrial tachycardia by about 40 msec.
Conclusion: This report presents another case in which radiofrequency catheter ablation was used in a patient with dextrocardia. Atrial tachycardia in patients with congenital heart disease may be difficult to control pharmacologically; however, the use of radiofrequency catheter ablation could be recommended as an alternative to medication and surgery.