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Variation in left ventricular regional wall stress with cine magnetic resonance imaging: normal subjects versus
N Fujita1, A J Duerinekx, C B Higgins
1Department of Radiology, University of California, San Francisco 94143-0628.
Insights
End-systolic wall stress increases from apex to base in both healthy individuals and dilated cardiomyopathy (DCM) patients. Ejection fraction decreases regionally, inversely correlating with wall stress.
Area of Science:
- Cardiology
- Medical Imaging
- Biomedical Engineering
Background:
- Left ventricular wall stress and ejection fraction are critical indicators of cardiac function.
- Dilated cardiomyopathy (DCM) significantly impairs myocardial contractility and ventricular remodeling.
- Understanding regional variations in cardiac mechanics is essential for diagnosing and managing heart conditions.
Purpose of the Study:
- To investigate the regional variations of end-systolic wall stress (ESWS) and ejection fraction (EF) throughout the left ventricle.
- To compare these regional mechanical parameters between normal subjects and patients with dilated cardiomyopathy (DCM).
Main Methods:
- Utilized cine magnetic resonance imaging (MRI) to acquire short-axis views of the left ventricle.
- Measured end-systolic wall stress and regional ejection fraction at multiple levels from apex to base.
- Analyzed data from both healthy volunteers and individuals diagnosed with DCM.
Main Results:
- A consistent gradient was observed, with increasing ESWS and decreasing EF from the apex to the base in both groups.
- Patients with DCM exhibited significantly higher ESWS compared to normal subjects across all ventricular levels (p < 0.01).
- Regional EF demonstrated an inverse relationship with regional ESWS in both normal and DCM cohorts.
Conclusions:
- Regional variations in end-systolic wall stress and ejection fraction exist within the left ventricle in both healthy individuals and DCM patients.
- Elevated end-systolic wall stress is a characteristic finding in dilated cardiomyopathy.
- The inverse relationship between regional ejection fraction and end-systolic wall stress highlights mechanical alterations in DCM.
Abstract:
We measured the variation of end-systolic wall stress and its relation to regional ejection fraction in short-axis planes through the left ventricle in normal subjects and in patients with dilated cardiomyopathy (DCM) by cine magnetic resonance imaging. There was a gradual increase in end-systolic wall stress but a gradual decrease in ejection fraction from apex to base in normal subjects (14 +/- 6 to 52 +/- 15 kdyne/cm2, 78% +/- 12% to 62% +/- 8%) and in patients with DCM (49 +/- 28 to 130 +/- 30 kdyne/cm2, 40 +/- 18 to 23% +/- 9%). The end-systolic wall stress in patients with DCM was higher than in normal subjects at every level (p < 0.01). We conclude that there is a variation in end-systolic wall stress in both normal subjects and patients with DCM with regional ejection fraction inversely related to regional end-systolic wall stress.