GJA1 and atrioventricular block: Specific knockout of Cx43 in CX3CR1+ cells leads to atrioventricular conduction abnormalities, but not atrioventricular block as observed in Cd11bDTR‐mediated macrophage depletion,25 this phenomenon could be attributed, at least in part, to the modulation of cardiac myocyte gap junction proteins, specifically Cx43, which are regulated by amphiregulin derived from macrophages.