Aims

The MicraVR™ transcatheter pacing system (TPS) has been implemented into clinical routine for several years. The primary recipients are patients in need for VVI pacing due to bradycardia in the setting of atrial fibrillation (AF). Implantation safety and acute success have been reported earlier.

So far only few long-term real-life data on TPS exist. We report indication, procedure but foremost TPS outcome data from two high-volume implanting German centers.

Methods

Between 2016 and 2019 188 patients were included. Procedural and acute outcome data were obtained. During follow up (FU) TPS interrogation was performed after 4 weeks and every 6 months.

Results

In all patients TPS implantation was successful. Indication for TPS implantation in 159/188 (85%) patients was permanent or intermittent AV block III° in the setting of persistent or permanent atrial fibrillation. Further indication for TPS implantation consisted of: sinus node dysfunction (7%), intermittent higher AV blockage in setting of sinus rhythm (6%) and other indications (e.g anatomical obstacles) (2%). The mean procedure duration was 50 min [35.0-70.0]. The average acute values after system release were: thresholds: 0.5V [0.38-0.74]/0.24ms; R-wave sensing: 10.0mV [8.1-13.5]; impedance: 650 Ohm [550-783], RV-pacing demand: 16.9 % [0.9-75.9], battery-status: 3.15 V [3.12-3.16].

During FU of 723.4±597.9 days neither pacemaker failure nor infections were reported. Measurements during long-term FU: thresholds: 0.5V [0.38-0.63]/0.24 ms; sensing: 12.3mV [8.9-17.2]; impedance: 570 Ohm [488-633], RV-pacing demand: 87.1% [29.5-98.6], battery-status 3.02 V [3.0-3.1]. 43 patients died from not-device related causes. Despite a significant increase in RV-pacing demand during FU, the projected battery longevity seems to be unaffected and even outperform initial expectations (Figure 1,2).

Conclusion

This to date largest German long-term data set for MicraVR™ TPS implantation revealed stable device parameter. Foremost, battery longevity seems to fulfill predicted values despite an increase in RV-pacing demand over time. Of note, no infections or system failure were observed.

Figures

Figure 1: RV pacing [%] during follow-up.
FU: follow-up.

Figure 2: Battery [V] during follow-up.
FU: follow-up.