Abstract Background Incessant tachycardias can severely impair cardiac function, which is known as tachycardia-induced cardiomyopathy (TIC). The cornerstone of successful therapy is heart rate control. Otherwise, heart failure requiring mechanical circulatory support (MCS) and ultimately heart transplantation may evolve. We report a case of successful weaning from MCS after severe TIC due to the very rarely incessant atypical atrioventricular nodal reentrant tachycardia (aAVNRT) with subsequent successful radiofrequency ablation (RFA). Case summary An eight-years-old girl was transferred to our unit with severely impaired cardiac function and went into circulatory collapse, including cardiopulmonary resuscitation. Stabilization was possible only by MCS, first by venoarterial extracorporeal membrane oxygenation, switched to long term MCS (Berlin heart EXCOR® Pediatric). However, pharmacological control of heart rate allowed myocardial recovery and finally the device was successfully explanted. As TIC was causative for the cardiomyopathy, the patient underwent invasive electrophysiologic mapping and subsequent curative ablation of an aAVNRT. Discussion This case report describes technical considerations of both, the special electrophysiological aspects of this rare tachycardia and the weaning protocol from a pulsatile ventricular assist device in a young child that finally recovered from TIC. Pharmacological heart rate control delayed curative RFA until explantation of the MCS.