Electrocardiographic mapping (ECM) is a noninvasive technique using body surface potentials and CT geometry to reconstruct epicardial maps. ECM is emerging as an important tool not only for diagnostic mapping, but also as a guide for trans-catheter ablation of complex arrhythmias such as atrial fibrillation. It provides the clinician with an immediate global view of the substrate, allowing easier pre-procedural planning, potentially improving clinical outcomes. Panoramic mapping of ventricular fibrillation (VF) is helping to develop a better understanding of its physiology, with future implications for the identification of therapeutic targets in patients with structural heart disease, as well as in idiopathic VF.