A cardiac electrophysiology system including a means for identifying the source of an arrhythmia in the heart is disclosed. The disclosed system may be an electrocardiograph device and may generate an enhanced electrocardiogram (EKG) of a cardiac structure. The disclosed system may include a disclosed catheter inserted into a chamber of the cardiac structure. The disclosed catheter may include electrodes configured to measure an analog electrical signal of the electrical activity of the cardiac structure over time, and a transformer configured to remove a direct current (DC) offset of the analog electrical signal to generate an analog electrical signal centered at 0 volts (V), which may be sampled by an analog-to-digital converter (ADC) and gain adjusted to a maximum resolution of the ADC to produce an enhanced digital electrocardiogram (EKG) signal.