In this article, we aim to investigate the electromagnetic (EM) THz (0.1 THz to 10 THz) signal loss by considering the reflections across the different layers of the human heart wall. We model the human heart wall as a multi-layer heterogeneous dielectric media and apply the theory of transmission laws from EM theory to study the phenomena of multiple reflections. On evaluating the intrinsic impedance of each layer, reflection coefficient across each interface, and overall reflection coefficient we observe that the epicardium layer provides maximum impedance to signal propagation in the THz band and hence the interfaces sharing the epicardium layer are more prone to reflect signals due to a higher reflection coefficient. Finally, the power reflected and transmitted from the final interface compared to the transmitted power from the initial layer is calculated using the overall reflection coefficient which is estimated via a black box concept. The results reveal that although up to a maximum of \(25\%\) of the initial transmitted power can be lost due to reflection when the frequency of operation belongs to the lower end of the considered spectrum, the value reduces to a mean of \(2.5\%\) as the frequency of operation increases.