Background and Objectives: The relationship of cold pressor, hyperventilation and exercise test responses to circadian patterns and types of angina in vasospastic angina have still not been known. The aim of this study was to identify subgoups of patients who have similar clinical features and provocation test response.
Materials and Methods: Twenty-one consecutive patients with pure vasospastic angina were studied. Six
exercise tests were performed in the early morning, late morning, and late afternoon in consecutive days, and 2 hyperventilation tests and 2 cold pressor tests in the early morning. Circadian distribution and types of angina (at rest, on physical activity or both) were evaluated by clinical history, clinical records and ambulatory ECG recordings during admission and follow-up periods (mean 19±9 months).
Results: Three patterns of circadian distribution of anginal attacks were identified during all observation periods together (morning and night: MN n=4, morning and afternoon or evening: M+F/E n=6, morning, night and afternoon and/or evening: MN+F/E n=11). Exercise test was positive in 36%(40/111) without circadian variation, hyperventilation test in 66%(23/35) and cold pressor test in 6%(2/33). Neither hyperventilation test nor cold pressor test was related to circadian patterns, types or activity of angina, or numbers of spastic artery. But positive exercise test increased significantly in patients with angina on physical activity (43% vs 21%, p<0.05), high activity (57% vs 18%, p<0.01), multivessel spasm(50% vs 27%, p<0.05 ) and circadian patterns of M+F/E and MN+F/E (29%, 55% vs 4%, p<0.05, p<0.01). All patients with MN had rest angina and single vessel spasm. All 6 patients with M+F/E had angina both at rest and on physical activity and 5 single vessel spasm. Eight of 11 patients with MN+F/E had angina both at rest and on physical activity and 8 multivessel spasm.
Conclusion: These findings suggest that hyperventilation test is highly sensitive in vasospastic angina without any relationship to clinical features, but exercise test response is related well to circadian patterns of angina attacks which are associated with characteristic clinical features.
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