Introduction: Clinically significant supraventricular tachycardia (SVT) may occur after a heart transplant, and there are reports of successful catheter ablation in these patients. Individual cases of typical flutter, accessory pathways and atrioventricular nodal reentrant tachycardia (AVNRT) ablation are described in patients with transplanted heart (1, 2).

Case report: Two years ago, 50-years-old patient underwent a heart transplant (biatrial technique) due to terminal dilated cardiomyopathy. The early postoperative course was complicated by persistent supraventricular tachycardia with the heart rate of 150/min, which was interpreted as an atrial flutter. Echocardiography described reduced systolic function of the graft with LVEF of 40%. Cellular and humoral rejection were ruled out and coronarography was normal. After drug-conversion to sinus rhythm left ventricular function gradually normalized. Tachycardiomyopathy due to SVT was set as the possible etiology of reduced graft function. During a recent hospital stay, long bursts of SVT were recognized. Arrhythmia was interrupted by adenosine, and telemetry recordings revealed that tachycardia begin with a long PR interval after which P waves disappeared and pseudoR pattern appeared in lead V1. Despite the antiarrhythmic therapy with propafenone and bisoprolol tachycardia recurred several times a day and lasted for several hours. We performed a standard electrophysiology study with 3 catheters and typical AVNRT was diagnosed. Radiofrequent ablation of the slow pathway was performed at a typical anatomical site. The fact that it was a heart transplant had no greater impact on catheter ablation. Procedure was performed without complications and arrhythmia did not reoccur.

Conclusion: Supraventricular tachycardia may complicate the postoperative course after a successful heart transplant, and even be the cause of graft dysfunction. Catheter ablation is an effective in this group of patients, and to our knowledge has not yet been described in the Republic of Croatia.