Demonstrating changes in brachial artery diameter, with FMD transient response following cuff deflation at 5 min (frame ∼1800) and sustained NMD response following administration of sublingual GTN (frame ∼600), recording at a rate of 5 frames per second. Demonstrating changes in brachial artery diameter, with FMD transient response following cuff deflation at 5 min (frame ∼1800) and sustained NMD response following administration of sublingual GTN (frame ∼600), recording at a rate of 5 frames per second. David R Warriner et al. Open Heart 2016;3:e000391 ©2016 by British Cardiovascular Society