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Correlation of coronary arteriography after acute myocardial infarction with predischarge limited exercise test
L S Griffith1, E Varnauskas, J Wallin
1Department of Medicine, Sahlgrenska Hospital, Gothenburg, Sweden.
Insights
Post-acute myocardial infarction patients with ST-segment depression on exercise tests show more severe coronary artery disease and viable myocardium. This helps explain higher cardiac death risk in these patients.
Area of Science:
- Cardiology
- Clinical Medicine
- Diagnostic Testing
Background:
- Prior studies link predischarge exercise test ST-segment depression in myocardial infarction patients to increased cardiac death risk.
- Understanding the underlying angiographic differences is crucial for risk stratification.
Purpose of the Study:
- To compare coronary artery disease extent, distribution, and left ventricular dysfunction in post-acute myocardial infarction patients based on exercise test results.
- To identify specific angiographic findings that may explain differing outcomes.
Main Methods:
- Compared 45 patients with >=1 mm ST depression (positive-result group) to 78 patients with <1 mm ST depression (negative-result group) after myocardial infarction.
- Performed cardiac catheterization ~50 days post-myocardial infarction.
- Assessed coronary narrowings, left ventricular dysfunction, and wall motion.
Main Results:
- Positive-result group had significantly more multivessel coronary artery disease (80% vs 47%) and severe narrowing in LAD and left circumflex arteries.
- Proximal LAD segment narrowing was more frequent in the positive-result group (58% vs 29%).
- Positive-response patients more often showed viable but potentially ischemic myocardium (93% vs 63%). Ejection fraction was similar between groups.
Conclusions:
- ST-segment depression on predischarge exercise tests in myocardial infarction patients is associated with more extensive coronary artery disease and impaired myocardial viability.
- These angiographic differences provide a potential explanation for the higher subsequent cardiac death risk observed in patients with positive exercise test results.
Abstract:
This study of post-acute myocardial infarction (AMI) patients compared the extent and distribution of coronary narrowings and left ventricular dysfunction in 45 patients who had greater than or equal to 1 mm ST-segment depression on a predischarge low-level exercise test (positive-result group) with those found in 78 patients who had less than 1 mm ST depression (negative-result group). Cardiac catheterization was done 50 +/- 20 days (mean + standard deviation) after AMI. Patients with positive responses more often had multivessel coronary artery disease (80 vs 47%, p = 0.001) and a greater than or equal to 75% narrowing in the left anterior descending (LAD) (87 vs 62%, p = 0.003) and left circumflex (71 vs 37%, p = 0.001) arteries, as well as in the proximal LAD segment before the first septal branch (58 vs 29%, p = 0.002). Among patients with positive responses 93% had normal or hypokinetic wall motion in the vascular territory of a severely diseased coronary artery (viable but potentially ischemic myocardium) while 63% of the negative-result group had these findings (p = 0.001). No difference in ejection fraction could be identified between the 2 groups (54 +/- 15% vs 54 +/- 16%). Prior studies of AMI patients have shown that ST-segment depression on a predischarge low-level exercise test will identify patients at higher risk of subsequent cardiac death. Our observations have identified differences in cardiac angiographic findings between patients with positive and negative responses to this test that may explain this difference in outcome.