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Natural history and evaluation of ST segment changes and MB CK release in acute myocardial infarction
Insights
ST segment elevation on ECG is an unreliable indicator of ischaemic myocardial damage extent. However, the pattern and timing of ST changes may help assess the progress of myocardial infarction.
Area of Science:
- Cardiology
- Biomedical Engineering
Background:
- Electrocardiogram (ECG) ST segment elevation is often used to assess myocardial infarction.
- The relationship between ST segment elevation and the extent of myocardial damage requires further investigation.
Purpose of the Study:
- To evaluate the reliability of ST segment elevation as a measure of ischaemic myocardial damage extent.
- To explore the potential of ST segment changes in monitoring myocardial infarction progression.
Main Methods:
- Analysis of variance was used to test the reproducibility of precordial mapping.
- Measurements of sigma ST elevation and plasma MB CK activity were taken in patients with and without infarction complications.
- Correlation analysis was performed between sigma ST elevation and MB CK activity.
Main Results:
- Factors like time since infarction onset and patient posture significantly affect ST elevation measurements.
- A weak correlation was found between early ST elevation and total MB CK activity, but not at other times.
- ST segment changes in patients with complications differed significantly from uncomplicated cases.
Conclusions:
- ST segment elevation is an unreliable quantitative measure for the extent of ischaemic damage.
- The dynamic pattern and time course of ST segment changes show potential for assessing myocardial infarction progression.
Abstract:
The experimental evidence relating ST segment elevation in the electrocardiogram to the progress and extent of ischaemic myocardial damage is discussed. There are difficulties in applying this to patients: the reproducibility of praecordial mapping was tested using a multiple analysis of variance. This showed that factors such as time after the onset of myocardial infarction and posture can affect measurements of sigmaST elevation significantly. There was a pattern of changes in segmaST elevation and of changes in plasma MB CK activity in a group of patients with uncomplicated anterior infarction. A significant byt weak correlation was found between sigmaST elevation in the first hour and the total MB CK activity released into the plasma, but not at any other time. The use of sigmaST elevation as a measure of the extent of ischaemic damage is unreliable. In 5 patients with a variety of complications of acute anterior infarction, changes in sigmaST elevation werr significantly different from the uncomplicated group, and MB CK release profiles suggested further necrosis. The pattern and time course of ST segment changes may be of use in assessing the progress of ischaemic myocardial damage.