BMP4 and atrial fibrillation: Normalized to DNA content in pellets at day 26, the relative LDH activity was decreased by BMP-4 at concentrations >0.4 ​nM in NP cells (P ​< ​0.01 ​at 0.4 ​nM, P ​< ​0.001 ​at 2 ​nM and 4 ​nM) and at ​> ​2 ​nM in AF cells (P ​< ​0.001 ​at 2 ​nM and 4 ​nM) compared to the non-treated control.