How to select target sites in electrogram-guided ablationoptions, techniques, and results

Electrogram (EGM)-guided approaches to atrial fibrillation (AF) ablation have emerged as a significant alternative conceptual paradigm over the past decade. This chapter discusses the genesis, technique, and clinical results of EGM-guided ablation approaches and their influence on contemporary clinical practice. EGM-guided ablation techniques may be broadly classified into strategies aimed to target signals with specific characteristics in the time domain (complex fractionated atrial electrograms (CFAE)) or in the frequency domain (dominant frequency (DF)). Clinical and experimental evidence has suggested that the predominant triggers for AF episodes arise via ectopic impulses from the pulmonary veins with a subsidiary role for AF triggering from other structures including the superior vena cava, and coronary sinus. The chapter explains important nuances of CFAE ablation based on the author's experience and discusses some areas of controversy. Mapping using monophasic action potentials has been suggested to more accurately identify the drivers of AF.