Cardiac Na+/Ca2+ exchange activity in patients with end-stage heart failure

Abstract

In human end-stage heart failure the increased sarcolemmal Na+/Ca2+-exchanger activity appears to be due to an elevated expression of this protein. An increase in the expression and activity of the Na+/Ca2+-exchanger in the failing human heart may be of important functional significance: while a resulting increase in Ca2+ extrusion across the sarcolemma may limit diastolic Ca2+ overload, a corresponding influx of Na+ may be associated with membrane depolarization and enhanced arrhythmogenesis if the Na+/Ca2+-exchanger operates primarily in the forward mode.