What is the clinical evidence from this study?

Study design: Observational. Population: Variant form of angina pectoris (n=21). Intervention: Untreated state (frequent spontaneous attacks) vs. Treated state (spontaneous attacks abolished by calcium antagonists or nitrates). Primary outcome: Exercise-induced ST elevation.

January 1, 1983Open Access

Exercise test in variant form of angina pectoris. Comparison of the results with spontaneous attacks.

Key Result

Exercise testing induced ST elevation in 79% of untreated patients with variant angina, whereas no ST elevation occurred in patients after treatment abolished spontaneous attacks.

Study Design

Type

Observational (n=21)

Multicenter

Structured PICO

What are the electrocardiographic and clinical responses to exercise testing in treated versus untreated patients with variant angina?

Population

21 patients aged 37 to 69 years with variant angina underwent exercise testing to compare electrocardiographic responses during untreated periods with frequent spontaneous attacks versus after treatment.

Exposure

Exercise testing

Comparator

Treated versus untreated patients (and comparison with spontaneous attacks)

Outcome

Exercise-induced ST segment changes (elevation or depression) and anginal attackssurrogate

Exercise testing in untreated variant angina frequently induces ST elevation likely due to coronary spasm, whereas in treated patients it may unmask underlying organic coronary stenosis via ST depression.

Main Result

Absolute Event Rate: 79% vs 0%

Limitations

Small sample size of 21 patients.
Not all patients underwent both untreated and treated exercise tests (only 8 patients had both).
Coronary angiography was not performed in all patients.
Low reproducibility of exercise-induced ST elevation threshold in repeated tests.

Abstract

Exercise tests were performed in 14 patients with untreated variant angina with frequent spontaneous attacks and in 15 patients after treatment abolished the attacks. (1) Anginal attacks associated with ST elevation were induced by exercise in 79% of untreated patients. By contrast, ST elevation was not observed in treated patients and ST depression was induced in 53% of the cases. (2) Exercise-induced ST elevation in untreated patients was shown in the same leads as the spontaneous attacks. (3) Exercise-induced ST elevation appeared initially during the recovery phase after exercise in 36% of untreated patients. Exercise-induced ST depression appeared during or immediately after exercise. (4) The reproducibility of exercise-induced ST elevation was low with repeated tests at different stages, but exercise-induced ST depression was consistently observed. (5) The exercise-induced ST depression and lack of ST changes in treated patients were highly suggestive of the presence and absence of organic coronary artery disease, respectively. However, the exercise-induced ST elevation in untreated patients did not differentiate between the presence or absence of organic stenosis of the coronary arteries. The results of exercise tests vary with the stage of variant angina. It is suggested that a coronary arterial spasm is a trigger mechanism for exercise-induced angina in cases of variant angina with frequent spontaneous attacks.

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