BMP4 and atrial fibrillation: As seen in Fig. 1, Fig. 2A, the DNA content was significantly higher in BMP-4 treated pellets, at doses higher than 2 ​nM, compared to non-treated controls in both NP (P ​< ​0.01 ​at 2 ​nM, P ​< ​0.001 ​at 4 ​nM) and AF (P ​< ​0.001 ​at 2 ​nM and 4 ​nM) cells.