New Insights Into Pacemaker Activity

“In this nice and detailed review of the complex interaction of multiple ion currents in animal SAN pacemaker activity, the authors also provided an elaborate overview of the structure of human SAN. In addition, based upon clinical data from gene mutation carriers, they proposed that the hyperpolarization-activated current (If) and fast sodium current (INa) contribute to human SAN pacemaker activity. Yet, direct evidence that If and INa are present in the human SAN was lacking. Therefore, we were particularly pleased by their inclusion of new data on expression of ion channel proteins in human SAN, as revealed by immunohistochemistry.”