Leadless pacing using the transcatheter pacing system (Micra TPS) in the real world: initial Swiss experience from the Romandie region—Authors’ reply

We thank Dr Garweg and Dr Willems for their opinion.1 Dr Garweg raises the point that complications with Micra implantation are rare in his hands. We note however that he reported a patient with presyncope due to loss of function of the Micra device, which needed to be repositioned during open heart surgery.2 It is important to stress that this major complication occurred during his learning curve, and that his 1.5% major complication rate reflects the experience of a single operator who had most probably reached the plateau of proficiency. Our almost seven-fold major complication rate of 9.8% reflects the initial experience of seven operators, and therefore results should be interpreted in light of these differences.3 We would like to correct the allegation that devices were not implanted according to recommendations by the manufacturer. All implanters had undergone mandatory training, with on-site technical assistance by the manufacturer during implantation. Medtronic does not currently recommend up to 10 redeployments in order to reach a capture threshold of <1 V/0.24 ms. In fact, they currently advise to consider accepting thresholds ≤2 V/0.24 ms based upon the very data cited by Drs Garweg and Willems which showed that moderately elevated thresholds at implantation decrease over follow-up.4 Dr Garweg and Dr Willems question the management regarding the patient who had ventricular tachycardia during catheter manipulation and without any further arrhythmias after Micra deployment. To the best of our knowledge, there is no evidence that mechanical induction of arrhythmias during leadless pacemaker implantation (which is also relatively common during standard pacemaker implantation) predicts future arrhythmias. We respectfully disagree that our definition of major complications differs from that of previous reports. The patient with intense tearing chest pain which occurred during implantation and which persisted during the days which followed, resulted in prolonged hospitalization (and was thus a major complication according to standard definitions). Finally, the authors criticize the implementation strategy of too many centres without necessary expertise, but we would like to remind them that this is a report of initial experience directly after the launch of the therapy (i.e. at a stage when no implanter can be considered to be an expert) in a geographical region of over two million inhabitants.