SLC30A1 and atrial fibrillation: The zinc level in heart tissues is approximately 1 g or less, and it has been shown to have a positive correlation with ejection fraction in humans.492 At a concentration of 1 nM, zinc can directly activate RyR2, which has a much higher affinity for zinc than Ca2+ (about three-fold), providing an essential mechanistic explanation for the association between zinc dyshomeostasis and certain cardiomyopathies.493,494 ZnT-1 is an endogenous negative regulator of the LTCC, particularly in the heart, where it appears to participate in cardiac electrical remodeling following atrial fibrillation.