HSPB1 and atrial fibrillation: Interestingly, it was found that overexpression of HSPB1 protects against contractile dysfunction by conservation of the cardiomyocyte structure in the tachypaced HL-1 cardiomyocyte model for AF and in clinical AF (Brundel et al. 2006a), suggesting HSPB1 to represent a druggable target in AF.