Elusive atrial substrate: complex fractionated atrial electrograms and beyond.

Most practitioners of atrial fibrillation (AF) ablation have attempted to move beyond pulmonary vein isolation into the realm of physiology-driven ablation for patients with persistent AF. This new strategy involves a combination of a common anatomic approach (with isolation of the pulmonary veins) and an individualized strategy tailored to the electrophysiologic characteristics of the atrial substrate present in each patient. In this review, we summarize the current reasoning and controversies related to this new approach. In addition, we attempt to unravel some of the complexities of targeting these patient-specific atrial electrical signals.