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Symptomatic and silent myocardial ischemia during exercise testing in coronary artery disease
Insights
Silent myocardial ischemia is common during exercise in coronary artery disease (CAD) patients. This study found no differences in patient characteristics between symptomatic and asymptomatic ischemic episodes during treadmill testing.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- Myocardial ischemia in coronary artery disease (CAD) patients during exercise can be silent or symptomatic.
- The relationship between silent and symptomatic ischemic episodes during exercise is not well-defined.
Purpose of the Study:
- To determine the prevalence of silent and symptomatic myocardial ischemia during treadmill exercise testing in patients with CAD.
- To investigate potential correlations between clinical, exercise, and angiographic factors and the occurrence of silent versus symptomatic ischemia.
Main Methods:
- 92 patients with angiographically documented CAD underwent treadmill exercise testing.
- Ischemic ST-segment depression and angina were recorded.
- Clinical, exercise, and angiographic data were analyzed for correlations with ischemia type.
Main Results:
- 42% of patients showed ischemia only, 46% angina only, and 12% had simultaneous ischemia and angina.
- Asymptomatic myocardial ischemia was common during exercise in CAD patients.
- No significant correlations were found between patient characteristics (age, sex, MI history, heart rate, ST depression, CAD extent, ejection fraction) and the frequency of symptomatic vs. asymptomatic ischemia.
Conclusions:
- Asymptomatic myocardial ischemia frequently occurs during exercise in patients with CAD.
- Patient characteristics do not differentiate between symptomatic and asymptomatic ischemic episodes during exercise in this population.
Abstract:
During exercise by patients with coronary artery disease (CAD), electrocardiographic evidence of myocardial ischemia may precede the onset of angina or may be unassociated with angina, even at peak levels of stress. However, neither the precise incidence of silent versus symptomatic ischemic episodes nor their interrelation in this setting has been clearly defined. The prevalence of silent and symptomatic myocardial ischemia during treadmill exercise testing was determined in 92 patients with angiographically documented CAD. The study group comprised 77 men (84%) and 15 women (16%) of mean age 57 years (range 32 to 79). Exercise testing resulted in ischemic ST-segment depression (greater than or equal to 1 mm for greater than or equal to 80 ms) only or in association with delayed (greater than or equal to 1 minute) angina in 39 patients (42%); angina only or in association with delayed ST-segment depression occurred in 42 patients (46%); and simultaneous occurrence of angina and ST-segment depression was noted in 11 patients (12%). Analysis of clinical, exercise and angiographic factors (age, sex, history of myocardial infarction, heart rate, maximal ST-segment depression, extent of CAD and left ventricular ejection fraction) revealed no significant correlation with the frequency of symptomatic and silent myocardial ischemia during exercise. Asymptomatic myocardial ischemia occurred commonly during exercise in patients with CAD, but there were no differences in the characteristics of patients with symptomatic and asymptomatic episodes.