Cardiac arrhythmias are a major cause of death (7 million cases annually worldwide; 400,000 in the U.S. alone) and disability. Yet, a noninvasive imaging modality to identify patients at risk, provide accurate diagnosis and guide therapy is not yet available in clinical practice. Nevertheless, there are various applications of electrophysiologic imaging in humans from ECG/CT reconstructions, MRI to tissue Doppler investigations that provide supplimentary diagnostic data to the cardiologist. EP laboratories are experiencing an increase in volume, for both diagnostic and interventional electrophysiology studies, including mapping, ablation, and pacemaker implants. The equipment requirements for these procedures are stringent, include positioning capabilities, and dose management. This book is designed to review all of the current imaging methodologies that assist in diagnosis within the electrophysiology department.