CACNA1C and atrial fibrillation: This is in line with observations in a canine model of atrial fibrillation induced by rapid pacing for 1, 7, and 42 days in which a continuous decrease in ICaL density in atrial cardiomyocytes was observed over the period investigated (Yue et al. 1997) as well as a decrease in mRNA expression of cacna1c (Yue et al. 1999).