Related Experiment Videos
The early diagnosis of acute myocardial infarction
S G Foy1, I C Kennedy, H Ikram
1Department of Cardiology, Princess Margaret Hospital, Christchurch, New Zealand.
Insights
The initial electrocardiogram (ECG) is more effective than the Rapitex serum myoglobin test for diagnosing acute myocardial infarction. The myoglobin test showed little diagnostic advantage over the ECG in this study.
Area of Science:
- Cardiology
- Medical Diagnostics
Background:
- Early diagnosis of acute myocardial infarction (MI) is crucial for patient outcomes.
- Electrocardiogram (ECG) is a standard initial diagnostic tool.
- Serum myoglobin assays offer potential for rapid MI detection.
Purpose of the Study:
- To compare the diagnostic utility of latex agglutination for serum myoglobin (Rapitex) against the initial ECG in patients suspected of acute MI.
- To evaluate the predictive value of each test for confirmed myocardial infarction.
Main Methods:
- Prospective evaluation of 40 patients with suspected MI.
- Initial ECG categorization into three groups based on abnormalities.
- Confirmation of MI by elevated creatine kinase (CK) and CK-MB fraction.
- Assessment of Rapitex serum myoglobin test results.
Main Results:
- Of 40 patients, 19 had confirmed MI.
- The initial ECG was significantly predictive of elevated CK (p = 0.003).
- Rapitex serum myoglobin test results were not predictive of elevated CK (p = 0.8517).
Conclusions:
- The initial ECG is a more reliable indicator for diagnosing acute MI compared to the Rapitex serum myoglobin test.
- The Rapitex serum myoglobin test provides minimal diagnostic or economic benefit over the initial ECG.
Abstract:
Latex agglutination for serum myoglobin (Rapitex) was compared with the initial ECG for the early diagnosis of acute myocardial infarction. Forty patients suspected of myocardial infarction were prospectively evaluated by initial electrocardiogram and Rapitex serum myoglobin. The initial ECG was categorised into one of three groups: Group 1 had ST segment elevation of at least 1 mm in a limb lead or 2 mm in a precordial lead (with or without Q waves); Group 2 had abnormalities other than those seen in Group 1; and Group 3 had no particular abnormalities present that is, a normal ECG. Myocardial infarction was confirmed by a rise in creatine kinase to greater than or equal to twice the upper limit of normal for our laboratory range and with a CKMB fraction of greater than 6%. Nineteen of 40 patients sustained myocardial infarction; nine ECG group 1, six ECG group 2, and four ECG group 3. Eleven of the 19 patients with myocardial infarction had positive serum myoglobin agglutination. The initial ECG was the most predictive of a subsequent rise in CK (p = 0.003), while Rapitex serum myoglobin determination was the least predictive (p = 0.8517). We conclude that the Rapitex serum myoglobin test offers little diagnostic or economic advantage over the initial electrocardiogram.