Significance of the walk-through angina phenomenon during exercise testing

Out of 3,900 patients who performed an exercise test at our clinic, 3 patients demonstrated a walk-through phenomenon (WTP), defined as the occurrence of mild angina during the first stages of exercise with disappearance of chest pain at higher workloads despite a greater pressure-rate product. 2 patients had variant angina, one with normal coronary arteries and the other with single vessel disease, while the third patient had stable exertional angina and a severe coronary artery disease with occlusion of two major vessels retrogradely filled by collateral channels. Repeat exercise tests failed to reproduce constantly the WTP in the 2 patients with variant angina, while in the third patient the phenomenon was repeatedly induced by exercise testing. Thus the WTP, although rarely found during exercise testing, can be observed in two subsets of patients. In variant angina the WTP is not reproducible and is probably due to coronary spasm, spontaneously subsiding during exercise. In patients with exertional angina and severe coronary artery disease, the WTP can be repeatedly observed during exercise and is likely to be secondary to a delayed vasodilation of collateral vessels. The clinical characteristics of the patients and the response to repeat exercise tests may be useful in identifying the different pathogenetic mechanisms.