STRESS TEST AND NITRATES

The use of sublingual nitroglycerin in the stress test is a precious t ool in everyday clinical cardiology. It has several indications in thi s context: 1) Confirmation of the diagnosis of myocardial ischaemia by eliminating a large number of false-positives with no marked variatio n of ST depression and performance after sublingual nitroglycerin in c ontrast with patients presenting authentic myocardial ischaemia on eff ort. 2) Teaching of the preventive and opportunistic use of nitroglyce rin before intense effort and before physical training which, in the l ong-term, is one of the most effective treatments of exertional angina pectoris. 3) Demonstration of potentiation of the effect of certain a ntianginal drugs such as beta-blockers. 4) In therapeutic trials, the stress test performed with sublingual nitroglycerin is used as a refer ence and to select patients capable of a fairly marked progression, so that they can be included in a protocol. It has the advantage of demo nstrating a functionally measurable improvement of the stress test wit h an appropriate drug. 5) Progression with sublingual nitroglycerin du ring the stress test is related to regression of ischaemia i.e. restor ation of functional viability of hibernating or shocked ischaemic segm ents of myocardium. It is probably the only realistic way to predict p ossible improvement after revascularization compared to other tests, w hich may be over-sensitive, as they detect zones with little capacity of regaining a viability which really contributes to cardiac output on exertion.