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"Silent" myocardial ischemia during and after exercise testing in patients with coronary artery disease
Insights
Silent myocardial ischemia during exercise testing is common in coronary artery disease (CAD) patients. This "silent" ischemia often occurs without chest pain and is not linked to obvious clinical or catheterization findings.
Area of Science:
- Cardiology
- Exercise Physiology
Background:
- Coronary artery disease (CAD) patients often exhibit positive exercise tests without chest pain.
- The prevalence and clinical significance of this "silent" ischemia remain unclear.
Purpose of the Study:
- To investigate the frequency and characteristics of silent myocardial ischemia during exercise testing in patients with CAD.
- To determine if clinical or angiographic factors predict silent ischemia.
Main Methods:
- Studied 122 stable CAD patients with angiographically defined stenosis (>75%) and positive exercise tests.
- Assessed clinical variables, prior myocardial infarction, comorbidities, medications, and left ventricular ejection fraction.
- Evaluated exercise test results for ST-T abnormalities and post-exercise ST depression.
Main Results:
- 44 patients (36%) had no exercise-induced pain, including 32 (26%) with no symptoms.
- No significant differences in clinical or angiographic features were found between patients with and without exercise-induced pain.
- Silent myocardial ischemia is not uncommon and not easily explained by standard clinical or catheterization data.
Conclusions:
- Silent myocardial ischemia during exercise testing is frequent in CAD patients.
- It is not associated with specific clinical or angiographic characteristics.
- Further research is needed to ascertain if silent ischemia increases the risk of sudden cardiac death.
Abstract:
Although many patients with coronary artery disease (CAD) have a positive exercise test without pain, the frequency and significance of this "silent" ischemia is unclear. Therefore, we studied 122 consecutive clinically stable patients with angiographically defined CAD (greater than 75 per cent luminal stenosis) and a positive exercise test. Seventy-eight patients had pain or anginal equivalent during or after a positive exercise test; 44 did not, including 32 (26 per cent) with no symptoms at all. Patients were evaluated as to age, sex, prior myocardial infarction, congestive failure, hypertension, diabetes mellitus, and digoxin or propranolol therapy--in addition to anginal symptoms before, during, or after the exercise itself. Extent of CAD, presence of collaterals, and left ventricular ejection fraction were also determined. All exercise tests were evaluated for evidence of ST-T abnormalities or prior infarction on the control ECG as well as peak heart rate during exercise and post-exercise degree of ST segment depression. There were no significant differences between patients with and without exercise-induced pain in regard to any of the clinical and angiographic features noted above, demonstrating that "silent" myocardial ischemia during or after exercise testing is not uncommon and is not readily attributable to any obvious clinical or catheterization findings. Further studies are necessary to determine if patients with evidence of "silent" myocardial ischemia are especially prone to sudden death.