We describe the case of a 30-year-old female patient who developed an interatrial tachycardia from the recipient to the donor atrium associated with signs of congestive heart failure 5 years after orthotopic heart transplantation. The patient underwent catheter mapping followed by successful radiofrequency (RF) ablation at the site of the presumed electrical connection between the recipient and the donor atria, through the interatrial surgical suture line, with stable recovery of sinus rhythm and disappearance of signs of left ventricular dysfunction. RF catheter ablation is confirmed to be feasible and safe in the treatment of heart transplant patients even in the presence of rare forms of arrhythmias, thus offering a cure for tachycardia to these patients.