Factors Influencing Pacemaker Generator Longevity: Results from the Complete Automatic Pacing Threshold Utilization Recorded in the CAPTURE Trial

Implant efficiency and clinical performance of Aveir™ VR and Micra™ VR leadless pacemaker: A multicenter comparative analysis of 67 patients

INTRODUCTION

Leadless pacemaker (LP) is a novel pacemaker that has been proven to be effective and safe; however, the majority of LPs in previous reports were the Medtronic Micra™ VR LP. We aim to evaluate the implant efficiency and clinical performance of the Aveir™ VR LP compared to the Micra™ VR LP.

METHOD

We performed a retrospective analysis in two healthcare systems (Sparrow Hospital and Ascension Health System, Michigan) in patients implanted with LPs between January 1, 2018, and April 1, 2022. The parameters were collected at implantation, 3 months and 6 months.

RESULTS

A total of 67 patients were included in the study. The Micra™ VR group had shorter time in the electrophysiology lab (41 ± 12 vs. 55 ± 11.5 min, p = .008) and shorter fluoroscopic time (6.5 ± 2.2 vs. 11.5 ± 4.5 min, p < .001) compared to the Aveir™ VR group. The Aveir™ VR group had a significantly higher implant pacing threshold compared to the Micra™ VR group (0.74 ± 0.34 mA vs. 0.5 ± 0.18 mA at pulse width 0.4 ms, p < .001), but no difference was found at 3 months and 6 months. There was no significant difference in the R-wave sensing and impedance and pacing percentage at implantation, 3 months, and 6 months. Complications of the procedure were rare. The mean projected longevity of the Aveir™ VR group was longer than the Micra™ VR group (18.8 ± 4.3 vs. 7.7 ± 0.75 years, p < .001).

CONCLUSION

Implantation of the Aveir™ VR required longer laboratory and fluoroscopic time, but showed longer longevity at 6 months follow-up, compare to the Micra™ VR. Complications and lead dislodgement are rare.

Wireless Power Transmission for Implantable Medical Devices Using Focused Ultrasound and a Miniaturized 1-3 Piezoelectric Composite Receiving Transducer

Wireless power transmission (WPT) using ultrasound is a promising way for wirelessly recharging implantable medical devices (IMDs). However, the transmitted power using ultrasound so far is insufficient for driving the existing IMDs. Moreover, the size of the receiving transducer is larger, which is not suitable for implantation. To increase the output power and reduce the size of the implantable receiver, this article presents a method of combining focused ultrasound with a miniaturized 1-3 piezoelectric composite receiving transducer to produce higher electrical power. An analytical fluid-structure interaction model is constructed to fully understand the operating mechanism of the receiving transducer under ultrasonic force. In our experiments, a miniaturized 1-3 piezoelectric composite receiving transducer with a diameter of 3.7 mm was used. The output power generated from the receiving transducer reached 60 mW at a distance of 150 mm. In vitro and in vivo animal experiments proved that the miniaturized transducer could successfully receive focused ultrasonic energy and convert it to electrical power. The method presented and the electrical power that we obtained can provide a valuable reference for wirelessly charging of IMDs.

Multifunctional Pacemaker Lead for Cardiac Energy Harvesting and Pressure Sensing

Biomedical self-sustainable energy generation represents a new frontier of power solution for implantable biomedical devices (IMDs), such as cardiac pacemakers. However, almost all reported cardiac energy harvesting designs have not yet reached the stage of clinical translation. A major bottleneck has been the need of additional surgeries for the placements of these devices. Here, integrated piezoelectric-based energy harvesting and sensing designs are reported, which can be seamlessly incorporated into existing IMDs for ease of clinical translation. In vitro experiments validate the energy harvesting process by simulating the bending and twisting motion during heart cycle. Clinical translation is demonstrated in four porcine hearts in vivo under various conditions. Energy harvesting strategy utilizes pacemaker leads as a means of reducing the reliance on batteries and demonstrates the charging ability for extending the lifetime of a pacemaker battery by 20%, which provides a promising self-sustainable energy solution for IMDs. The additional self-powered blood pressure sensing is discussed, and the reported results demonstrate the potential in alerting arrhythmias by monitoring the right ventricular pressure variations. This combined cardiac energy harvesting and blood pressure sensing strategy provides a multifunctional, transformative while practical power and diagnosis solution for cardiac pacemakers and next generation of IMDs.

Pacing and Sensing of Human Heart for over 31 Years with the Same Apparatus (Generator and Lead)

Several patients receive a permanent pacemaker in a relatively young age, with multiple subsequent reoperations for pacemaker replacement. Pulse generator replacement is an invasive procedure, associated with the risk of various complications, mainly infection and skin erosion. A case of an extremely long-lasting pacemaker with a totally uneventful longevity period over 31 years is presented. The explanation for this quite rare pacemaker longevity (possibly unique) is analyzed and discussed.