NOS2 and cardiomyopathy: With respect to congestive heart failure, valvular diseases, and other left heart pathologies (e.g., cardiomyopathy) that might lead to group 2 PH, iNOS expression was increased in hearts, macrophages, and blood vessels (endothelium and smooth muscle cells), irrespective of PH diagnosis [172,173,174,175,176,177,178,179,180,181,182,183,184,185,186,187,198,199].