TRPM7 and atrial fibrillation: In contrast to the data in isolated cardiac myocytes (where the fluorescence for TRPM7 is nearly one order of magnitude larger than for TRPM6), in cardiac tissue immunohistochemical analysis, the detected fluorescence intensities for TRPM6 and for TRPM7 were of the same order of magnitude, but still showed increased fluorescence levels (2.43 ± 0.067 a.u. and 3.16 ± 0.108 a.u., respectively, (n = 11–19) in AF vs. 1.58 ± 0.059 a.u. and 2.47 ± 0.109 a.u., respectively, (n = 11–19, p < 0.01) in SR) (Figure 8C).