This article presents an analytical model and characterization of path loss in a human heart-centric nanoscale network. The frequencies under investigation include the terahertz (THz) band (0.1–10 THz) and the optical band (400–750 THz). The path loss models incorporate the impact of spreading loss from signal propagation and absorption loss caused by different layers in the human heart. The results indicate a dependence of the path loss not only on the thickness of the different layers but also on the frequency of operations. The useful insights obtained from the path loss trends at the explored frequencies can facilitate the deployment of nanosensor networks for heart-centric communications.