A Dynamic High-Fidelity Equivalent Circuit Phantom for Intracardiac Communication in Pacemaker Indications

Conductive intracardiac communication (CIC) is an essential approach for achieving multichamber pacing in leadless pacemakers (LCPs), significantly enhancing the therapeutic outcomes for conditions, such as bradycardia. However, the characteristics of the intracardiac channel are profoundly affected by the heart’s rhythmic contractions. Accurately understanding the dynamic transmission mechanisms and channel parameters under various cardiac pathological states is crucial for enhancing the multichamber pacing functionality of LCPs. In this article, the relationship between cardiac chamber volume and channel impedance is mapped based on the electrocardiogram (ECG) data. This mapping enables precise, real-time adjustments to variable impedance, simulating the impedance changes occurring with each heartbeat. Through this approach, a time-frequency equivalent circuit phantom is proposed to accurately simulate channel characteristics for various pacemaker indications (PIs). Utilizing a quasi-dual-pump structural analogy to the heart, we designed a dynamic experimental measurement platform capable of simulating the cardiac beating process under various PIs, which is employed to validate the accuracy of the circuit phantom. The results demonstrate that the correlation coefficients in the frequency and time domains are greater than 0.9432 and 0.9150, respectively, with a time-domain consistency coefficient of less than 3.25. Through cross validation in both frequency and time domains, the circuit effectively simulates the channel characteristics of normal and PI hearts. The empirical formula established based on the time-domain measurement results can be utilized for the rapid estimation of the right atrium (RA)–right ventricle (RV) channel characteristics. The proposed phantom offers a highly accurate and reproducible experimental method for the design of intracardiac communication transceivers, advancing the development and validation of leadless multichamber pacemaker systems.