To the Editor- Rhythmologic challenges following heart transplantation.

Heterotopic heart transplantation (hHTx) was first performed in humans in 1974. It found its way into broader application in the late 1980s and early 1990s, especially for patients with elevated pulmonary vascular resistance. Laredo et al have recently described a case of successful catheter ablation of ventricular tachycardia in a patient 26 years after hHTx. This article is of particular interest for 2 reasons. First, it describes the challenging approach of performing catheter ablation in a setting of hHTx, especially for ventricular arrhythmia, which is only scarcely described in the literature. Second, the authors casually mention a case of internationally remarkable survival of 26 years after hHTx.

In our center we have performed hHTx in 1 child and 16 adult patients. The child showed cardiac recovery, allowing explantation of the transplanted heart about 4 years after hHTx. Four of the 16 adult patients displayed long-term survival of >10, >13, or >18 years, including 1 patient of 27 years survival by now. In 2 cases we faced complex ventricular arrhythmias, which were treated by medication/cardioversion, by an implantable cardioverter-defibrillator previously implanted in the native heart, or by external defibrillation. Even in orthotopic HTx, arrhythmias can be challenging as described for catheter ablation of atrial tachycardia because of recipient-to-donor transatrial conduction. Taken together, we fully support the article by Laredo et al with the messages that hHTx is capable of showing considerable survival in selected cases. We further stress that follow-up of patients who underwent HTx should comprise rhythmologic expertise since such patients have the potential to develop complex as well as HTx-specific and rarely seen arrhythmias.