Key result
Nitroglycerin did not substantially improve the ischemia threshold during atrial pacing in patients with coronary artery disease, which was reached at the same rate-pressure product in each case.
Why the study?
Does nitroglycerin improve pacing-induced myocardial ischemia in patients with CAD?
Observational (n=30)
Does nitroglycerin improve pacing-induced myocardial ischemia in patients with CAD?
The atrial pacing test reliably provokes myocardial ischemia and estimates CAD extent, but nitroglycerin does not substantially improve the ischemia threshold.
May identify ischemia threshold via PAm in CAD; hypothesis-generating and requires prospective validation before clinical use.
In 10 patients without and 20 patients with various degrees of angiographically proven CAD 93 pacing runs were studied. Changes of PAm, of ECG, and of anginal pain serving as parameters of myocardial ischemia were correlated to the rate-pressure-product. In patients without CAD no correlations could be ascertained. In each patient with CAD determination of ischemia was achieved reproducibly. Ischemia threshold is represented by a sharp increase of PAm. Ischemia threshold seems a parameter to be preferred as compared to pain threshold. The extent of CAD (angiographically estimated) correlates well with the pacing test especially when collaterals are taken into account. After NG no substantial improvement of ischemia can be detected: Ischemia threshold before and after NG was reached at same rate pressure in each case. We conclude the atrial pacing test to be an excellent test for the provocation of myocardial ischemia. The test is also useful for estimation of the extent of CAD.
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Schwarz et al. (1975) conducted an observational in Coronary artery disease (n=30). Nitroglycerin during atrial pacing vs. Before nitroglycerin was evaluated on Ischemia threshold (rate-pressure-product). Nitroglycerin did not substantially improve the ischemia threshold during atrial pacing in patients with coronary artery disease, which was reached at the same rate-pressure product in each case.
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