Among the many polymorphisms of the NOS3 gene, it is now evident that the intron 4b/4a, the G894T, and the T786C variants have important implications in the etiopathogenesis of cardiovascular diseases [8], [9], [10], [11], [12] and DCM being a complex disorder associated with heart failure may be one such CVD, with the underlying mechanism being oxidative stress. Here, NOS3 is linked to heart failure.