An intracardiac electrogram model to bridge virtual hearts and implantable cardiac devices

摘要

Virtual heart models have been proposed to enhance the safety of implantablecardiac devices through closed loop validation. To communicate with a virtualheart, devices have been driven by cardiac signals at specific sites. As aresult, only the action potentials of these sites are sensed. However, the realdevice implanted in the heart will sense a complex combination of near andfar-field extracellular potential signals. Therefore many device functions,such as blanking periods and refractory periods, are designed to handle theseunexpected signals. To represent these signals, we develop an intracardiacelectrogram (IEGM) model as an interface between the virtual heart and thedevice. The model can capture not only the local excitation but also far-fieldsignals and pacing afterpotentials. Moreover, the sensing controller canspecify unipolar or bipolar electrogram (EGM) sensing configurations andintroduce various oversensing and undersensing modes. The simulation resultsshow that the model is able to reproduce clinically observed sensing problems,which significantly extends the capabilities of the virtual heart model in thecontext of device validation.