Cardiac macrophages facilitate electrical conduction through the atrioventricular-node (AV) in mice. A possible role for cardiomyocyte-macrophage coupling on the effect of antiarrhythmic therapy has not been investigated yet. Holter monitoring was conducted in LysM^(Cre)xCsf1r^(LsL-DTR) mice (MM^(DTR)) under baseline conditions and after an elctrophysiological stress test by flecainide. In vivo effects were recapitulated in vitro by patch-clamp experiments. The underlying mechanism …