Regional diastolic wall motion dynamics in anterior myocardial infarction: analysis and quantification with magnetic
P A Dendale1, P R Franken, G J Waldman
1Department of Cardiology, Academic Hospital VUB, Brussels, Belgium.
Insights
Regional differences in heart function after myocardial infarction significantly impact global cardiac performance. Magnetic resonance imaging reveals increased asynchrony in contraction and relaxation in infarct patients, highlighting the value of advanced cardiac imaging.
Area of Science:
- Cardiovascular imaging
- Cardiac mechanics
- Medical diagnostics
Background:
- Regional variability in cardiac function is common in heart disorders.
- The impact of this heterogeneity on overall heart function is poorly understood.
- Conventional imaging methods struggle to assess this regional functional heterogeneity.
Purpose of the Study:
- To investigate the relationship between regional differences in cardiac wall motion and global diastolic function in patients with myocardial infarction.
- To evaluate the utility of magnetic resonance imaging (MRI) in assessing these functional dynamics.
Main Methods:
- ECG-triggered MRI was used to acquire midventricular short axis slices of the left ventricle.
- Eight infarct patients and 10 control volunteers were studied.
- The centreline method analyzed variations in wall thickness and slice cavity volume throughout the cardiac cycle.
Main Results:
- Infarct patients showed a significantly decreased peak filling rate (58 cm³/s) compared to controls (96 cm³/s).
- Analysis revealed increased asynchrony in both contraction (64 ms vs. 37 ms) and relaxation (88 ms vs. 51 ms) in infarct patients.
- Regional differences were most pronounced in the infarcted areas of the left ventricle.
Conclusions:
- Cardiac MRI enables the assessment of regional wall motion dynamics and their correlation with global diastolic function in infarct patients.
- Findings underscore the importance of regional functional assessment in understanding cardiac disorders post-infarction.
Background:
Regional variability in systolic and diastolic cardiac function occurs in most cardiac disorders. The influence of this regional functional heterogeneity on global function is not well understood and is difficult to study with the common imaging modalities.
Methods:
A midventricular short axis slice of the left ventricle was obtained with ECG-triggered magnetic resonance imaging in eight infarct patients and 10 control volunteers. The variation in wall thickness and slice cavity volume during the cycle was studied using the centreline method.
Results:
The peak filling rate was significantly decreased in the infarct group (96 versus 58 cm3/s, P < 0.005). In addition, a small contribution of other parameters, such as the time to end systole, the isovolumic relaxation time, and the duration and extent of early filling, was also shown by linear discriminant analysis. Analysis of the regional parameters demonstrated an increased asynchronicity of contraction (64 versus 37 ms, P < 0.01) as well as relaxation (88 versus 51 ms, P < 0.01) in patients with myocardial infarction. On comparison of the anterior (infarcted) and inferior (non-infarcted) parts of the left ventricle, the difference was present only in the infarct region.
Conclusion:
Magnetic resonance imaging of the heart allows evaluation of the relationship between regional differences in wall motion dynamics and global parameters of diastolic function in infarct patients.
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