A, Current-clamp protocol (0.5 Hz, top) together with simultaneous recordings of triggered AP (middle) and CaT (Fluo-3, bottom) in a Ctl (left) and in a cAF (right) myocyte. B, Mean±SEM resting membrane potential, AP amplitude, APD50 and APD90, respectively. C, Mean±SEM diastolic and systolic [Ca2+]i levels (left) and resulting CaT-amplitude (right). *P<0.05 vs. corresponding means in Ctl. Numbers indicate myocytes/patients.