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Electrocardiographically and symptomatically silent myocardial ischemia during exercise testing
C Kurata1, K Tawarahara, K Sakata
1Third Department of Internal Medicine, Hamamatsu University School of Medicine, Japan.
Insights
Silent myocardial ischemia during exercise is common in coronary artery disease (CAD) patients. Less severe ischemia and specific factors predict this silent condition, impacting diagnosis and treatment strategies.
Area of Science:
- Cardiology
- Exercise Physiology
- Diagnostic Imaging
Background:
- Coronary artery disease (CAD) can present with myocardial ischemia that is not always accompanied by chest pain or electrocardiographic changes.
- Identifying 'silent' ischemia is crucial for accurate risk stratification and management in CAD patients.
Purpose of the Study:
- To determine the frequency and characteristics of electrocardiographically and symptomatically silent myocardial ischemia during exercise in patients with documented CAD.
- To identify factors that differentiate patients with silent ischemia from those with symptomatic ischemia.
Main Methods:
- Studied 171 patients with angiographically confirmed CAD and scintigraphically confirmed ischemia.
- Classified patients into two groups: Group N (silent ischemia) and Group P (symptomatic ischemia).
- Utilized stepwise discriminant analysis to identify significant differentiating factors.
Main Results:
- 33% of patients (Group N) experienced silent ischemia during exercise.
- Group N patients had higher peak heart rate and rate-pressure product, but less severe scintigraphic ischemia, lower lung thallium-201 uptake, and fewer diseased vessels.
- History of effort angina, lung thallium-201 uptake, and scintigraphic ischemia severity were key discriminators.
Conclusions:
- Electrocardiographically and symptomatically silent myocardial ischemia is prevalent during exercise in CAD patients.
- Less severe ischemia appears to be a significant determinant of silent ischemia in this population.
Abstract:
Certain patients with coronary artery disease (CAD) may have neither ST depression nor chest pain during exercise despite the presence of myocardial ischemia. The frequency and characteristics of such electrocardiographically and symptomatically silent ischemia were studied in 171 patients with both angiographically documented CAD and scintigraphically documented ischemia. Fifty-six (33%) of 171 patients had neither ST depression nor chest pain (Group N), and 115 (67%) had ST depression and/or chest pain (Group P). The two groups were similar with respect to age, gender, the prevalence of prior infarction, and peak systolic blood pressure. Group N patients, however, had a higher mean peak heart rate and rate-pressure product, less severe scintigraphic ischemia, a lower lung thallium-201 uptake, and a smaller number of diseased vessels. Stepwise discriminant analysis showed a history of effort angina, lung thallium-201 uptake, and scintigraphic severity of ischemia to be significant discriminators between Groups N and P. In conclusion, electrocardiographically and symptomatically silent ischemia may be common during exercise in patients with CAD, and less severe ischemia may be one of important determinants.