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Cineangiographic evaluation of changes in regional left ventricular wall motion after acute myocardial infarction
1Second Department of Internal Medicine, Toyama Medical and Pharmaceutical University, Japan.
Insights
Left ventricular function after myocardial infarction shows regional changes. Normal heart regions may improve overall function during recovery after a heart attack.
Area of Science:
- Cardiology
- Cardiovascular Physiology
- Medical Imaging
Background:
- Acute myocardial infarction can lead to impaired left ventricular function.
- Assessing regional wall motion is crucial for understanding cardiac recovery.
- Intracoronary thrombolysis aims to restore blood flow but may not prevent all functional deficits.
Purpose of the Study:
- To evaluate the natural progression of regional left ventricular function after acute myocardial infarction.
- To quantify changes in segmental wall motion in both infarcted and non-ischemic areas.
- To determine the contribution of non-ischemic regions to overall left ventricular recovery.
Main Methods:
- Comparison of cineventriculograms from acute and chronic stages in ten patients.
- Superimposition of ventricular silhouettes using reference markers.
- Quantitative analysis of segmental centripetal wall motion using radial grids.
Main Results:
- Segmental wall motion in the infarcted area remained unchanged.
- Total systolic shortening in non-ischemic areas showed a trend towards increase.
- Ejection phase shortening significantly increased in non-ischemic regions (P < 0.05).
Conclusions:
- Regional left ventricular function exhibits distinct changes post-myocardial infarction.
- Non-ischemic myocardial segments may compensate for infarcted areas.
- Increased ejection phase shortening in normal regions contributes to left ventricular functional recovery.
Abstract:
To evaluate the natural course of changes in regional left ventricular function after acute myocardial infarction, we compared cineventriculograms taken during the acute and chronic stages of myocardial infarction in ten patients who had sustained coronary occlusion despite intracoronary thrombolysis. Three ventricular silhouettes (end diastole, aortic valve opening, and closure) were superimposed using external reference markers, and 36 radial grids were drawn from the center of gravity of the end-diastolic silhouette to the endocardial margin of each silhouette. Measurement of the length of each radial grid provided quantitative details of segmental centripetal wall motion. In the infarcted area, percentage total systolic shortening (% delta LTOT), iso-volumic shortening (% delta LISO), and ejection phase shortening (% delta LEJ) remained unchanged. In the nonischemic area, % delta LTOT tended to increase from 34% +/- 6% to 41% +/- 6%. Although % delta LISO was unchanged (9% +/- 4% vs. 8% +/- 1%), % delta LEJ increased from 25% +/- 4% to 37% +/- 6% (P less than 0.05). Thus, progressive increases in ejection phase shortening in normal regions may contribute to the functional recovery of the left ventricle after myocardial infarction.