Digital pulse plethysmography (DPG) in studies of the hemodynamic response to nitrates--a survey of recording methods and principles of analysis.

Digital pulse plethysmography (DPG) has proved a technically simple, noninvasive, sensitive and informative technique for studying the effects of nitroglycerin and other nitrates on peripheral arteries. The importance of performing nitrate evaluation by DPG mainly in elderly subjects is emphasized. On the basis of observations with DPG some indirect conclusions on the effect of nitrates on the coronary arteries are justified. A review, with recommendations based on own experience, is given of various recording techniques and principles of evaluating quantitatively the digital volume pulse contour, with special reference to the influence of nitrates on the position and appearance of dicrotism. DPG seems to be a convenient, noninvasive and helpful procedure in studies on the development of nitrate tolerance.