The EP-David simulator is a hands-on training tool designed to replicate a patient under an electrophysiological procedure. It simulates key physiological parameters such as respiration and temperature, and it generates realistic cardiac signals, including normal sinus rhythm and various types of arrhythmias, for diagnostic and therapeutic practice. However, its original signal creation workflow was fragmented and heavily dependent on MATLAB, limiting testing efficiency and physiological flexibility. This thesis presents the design and implementation of a fully Python-based graphical user interface (GUI) that enables the creation of both surface ECG and intracardiac signals (iECG) with customizable morphology, propagation timing, and amplitude. The interface allows users to fine-tune a pre-designed set of signals, construct activation sequences, visualize them in real-time, define region-specific signals, and export a structure compatible with the simulator’s runtime engine.