Implantation Of An Intracardiac Accelerometer With Transcorporal Communication System As A Bridge To Energy Harvester
Michiel Algoet, MD1, Alaa Makdissi, MSc2, Willy Regnier, MSc2, Marion Heurte, MSc2, Manon Van Hecke, MD1, Wouter Oosterlinck, MD PhD1.
1KU Leuven, Leuven, Belgium, 2Cairdac, Paris, France.
BACKGROUND:This study aims to assess the correlation between cardiac motion and available harvestable mechanical energy, we also want to assess sustainability and feasibility in a dual chamber model. METHODS:This study was approved by the ethics committee of the KU Leuven. Twenty-two pigs and one sheep were anesthetized and ventilated in dorsal decubitus. Arterial blood pressure (arterial catheter), saturation (oximeter) and heart rhythm (ECG) was continuously monitored. Twelve pigs received a sternotomy and wired sensors were sutured to several sites (right atrium, ventricular septum, left ventricle and apex right ventricle). Cardiac motion was assessed in baseline state, dobutamine and esmolol infusions and by electrical ventricular stimulation. Surgical venous access to the jugular vein was performed in seven pigs after administration of 100 IU/kg IV heparin the pigs received an accelerometer-capsule into the right ventricle through a 24 Fr jugular access sheath. ECG, 3D accelerations and arterial blood pressure was measured. One sheep was implanted with an energy harvester and had a follow-up of 3 months to assess communication and voltage stability. In a fourth test phase, 3 pigs received two capsules (atrium + ventricle) by femoral access to assess dual chamber functionality. RESULTS:Fifty-one various signals were recorded from the implanted sites and synchronized at 1000 samples per second. Analysis showed acceleration changes in every dimension following every ECG peak in both the wired sensor as the capsule model during various conditions. Based on acceleration analysis it is possible to calculate the mechanical energy which can be collected by an energy harvester. Chronic implantation in one sheep showed good communication (Bluetooth) and harvested power stability with limited fibrosis formation. Communication and acceleration studies in the dual chamber model showed sufficient mechanical energy to harvest. CONCLUSIONS:Cardiac motion analysis shows that heart mechanical energy is available after every ECG peak. Harvesting this energy is sufficient to support a self-autonomous leadless pacemaker and provide communication to an external server. Dual chamber implantation has been tested and is feasible in an acute pig model.
LEGEND:A, ECG vs motion and orientation in function of time. B, capsule(left) and wired sensor(right). C, sheep after implantation with communication system. 
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