Inappropriate single chamber ICD discharges due to supraventricular tachycardia with high degree atrioventricular block.

Supraventricular tachycardia with rapid ventricular response is well recognized as the more frequent cause of single chamber ICD inappropriate therapies. We report here a 18-year-old-woman with surgically corrected transposition of the great arteries who received repetitive inappropriate discharges from an ICD implanted for ventricular tachycardia. Rapid atrial activity during episodes of supraventricular tachycardia with high degree atrioventricular block was oversensed as ventricular fibrillation by a single chamber ICD causing repetitive painful discharges. Pharmacological treatment of the supraventricular tachycardia solved the problem.