Optical Mapping of the Sinoatrial Node and Atrioventricular Node

Technological advances often precede scientific breakthroughs that have led to leaps in our understanding of human physiology. The advent of the electrical galvanometer was a landmark advancement that enabled careful study of the electrical activation of the heart. Similarly, optical imaging, or mapping, using fluorescent, voltage sensitive dyes has enabled the careful study of the sinoatrial (SA) and atrioventricular (AV) nodes, and improved our understanding of how anatomic structure is related to electrophysiological function. We review the major findings of optical mapping studies of the sinoatrial node (SAN) and atrioventricular node (AVN), with particular emphasis on clinically relevant physiology and pathophysiology. We pay particular attention to clinical implications of these seminal findings derived from animal models and from the optical mapping study of human hearts. The studies presented are intended to improve the reader's understanding of SAN and AVN physiology, as well as to offer insight into the advantages and limitations of optical mapping.