Related Experiment Videos
Prevalence and clinical significance of silent myocardial ischemia in exercise test
M Murayama1, H Musha, K Sotozono
1Second Department of Internal Medicine, St Marianna University School of Medicine, Kawasaki-city, Japan.
Insights
Silent myocardial ischemia is common in patients with ischemic heart disease, often occurring without chest pain. Its consistent presence is rare, with higher incidence in old myocardial infarction than angina of effort.
Area of Science:
- Cardiology
- Ischemic Heart Disease
- Exercise Physiology
Background:
- Silent myocardial ischemia (SMI) is a significant clinical entity in patients with established ischemic heart disease.
- Understanding the prevalence and clinical significance of SMI during exercise testing is crucial for patient management.
Purpose of the Study:
- To determine the prevalence of silent myocardial ischemia during exercise testing in patients with known ischemic heart disease.
- To investigate the clinical significance and characteristics of transient ischemia with and without anginal pain.
Main Methods:
- Retrospective review of 749 exercise tests from 513 patients with confirmed ischemic heart disease.
- Analysis of the occurrence of transient ischemia, anginal pain, and other symptoms leading to test discontinuation.
Main Results:
- Transient ischemia occurred in 52% of tests; 30% were silent (no pain), and 22% were associated with pain.
- Anginal pain was more frequent in severe coronary artery disease and low exercise tolerance.
- Silent myocardial ischemia was observed in 3.7% of angina of effort cases and 12.3% of old myocardial infarction cases.
Conclusions:
- Silent myocardial ischemia is not rare in patients with ischemic heart disease and can occur without chest pain, potentially due to not reaching the angina threshold.
- The incidence of SMI is higher in old myocardial infarction compared to angina of effort, suggesting different underlying mechanisms.
- Further research is needed to elucidate the mechanisms of SMI and the differing incidence between various ischemic heart disease subtypes.
Abstract:
Prevalence of silent myocardial ischemia in exercise test was retrospectively reviewed from 749 tests performed for 513 patients with definite evidence of ischemic heart disease. The clinical significance was studied and absence of transient ischemia, occurrence of transient ischemia with and without pain were observed in 48%, 30% and 22% of the tests, respectively. Anginal pain was frequently observed in exercise tests for patients with severe coronary artery disease and low exercise tolerance. A large number of tests showing ischemic response were discontinued due to symptoms other than anginal pain and hence silent myocardial ischemia could be thought to be a result of ischemic state which does not reach the angina threshold. Silent myocardial ischemia was frequently observed during usual daily life. However, a definite correlation between severity of transient ischemia and presence or absence of chest pain in the same individuals was not obtained from the study. A day to day variation in the angina threshold might be responsible. In general, silent myocardial ischemia was not rare. However, the consistent condition was very unusual. In angina of effort (EA) and old myocardial infarction (OMI), 3.7% and 12.3% were silent, respectively. A higher incidence was obtained in OMI than in EA. This is important for the management of these patients. The mechanism of silent myocardial ischemia and the cause of the different incidence of this state between EA and OMI were not defined and remained to be further studied.