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Test of reliability of echocardiographic estimation of left ventricular dimensions and volumes
Insights
This study validates a novel echocardiographic method for assessing left ventricular function by measuring myocardial incompressibility. The test reliably estimates left ventricular wall volume, ensuring accurate cardiac cycle assessments.
Area of Science:
- Cardiology
- Medical Imaging
- Biomedical Engineering
Background:
- The incompressibility of myocardium is a fundamental principle in cardiac physiology.
- Accurate assessment of left ventricular (LV) volume is crucial for diagnosing cardiac conditions.
- Echocardiography is a widely used imaging modality for evaluating cardiac structure and function.
Purpose of the Study:
- To establish and validate a novel echocardiographic test based on myocardial incompressibility.
- To assess the reliability of echocardiographic measurements of LV dimensions and volumes.
- To determine the accuracy of LV wall volume calculations throughout the cardiac cycle.
Main Methods:
- Utilized echocardiographic measurements of LV cavity transverse dimension and wall thickness.
- Calculated LV wall volumes using both ellipsoid and cube geometric models.
- Analyzed systolic and diastolic wall volume estimates for correlation and agreement in 60 subjects.
Main Results:
- High correlation (r=0.96) was observed between systolic and diastolic LV wall volumes using the ellipsoid method, supporting measurement reliability.
- The cube method yielded similar correlations (r=0.94) but larger volume estimates.
- Reduced correlation was noted in patients with significantly enlarged LV cavities, indicating potential limitations.
Conclusions:
- The proposed echocardiographic test, based on myocardial incompressibility, reliably assesses LV dimensions and volume estimates.
- This method can be employed to evaluate the accuracy of echocardiographic data in individual patients.
- Further investigation may be needed for enlarged LV cavities to refine volume estimation accuracy.
Abstract:
This test is based on the incompressibility of myocardium, which dictates that left ventricular wall volume remains constant throughout the cardiac cycle. The volumes occupied by the left ventricular cavity, by ventricular wall plus cavity, and hence by ventricular wall alone were estimated, both at end-systole and at end-diastole, from ecocardiographic measurements of cavity transverse dimension and wall thickness. Wall volumes were determined by assuming an ellipsoid shape (the major axis being predicted from aggression equations relating angiocardiographic and echocardiographic cavity dimensions) and also by the cube method. A discrepancy between systolic and diastolic wall volume estimates indicates either that the measurements of ventricular dimensions were unreliable or that the assumptions of ventricular geometry involved in the volume calculations were incorrect. Studies were made on 60 subjects. Using the ellipsoid formula, values for wall volume ranged from 66 to 719 ml; systolic and diastolic wall volumes correlated closely (r = 0-96, mean difference = 6-8 +/- 0-9 (SEM) %) supporting the reliability of the echocardiographic dimensions and estimates of cavity and wall volume. In the 12 patients with very large end-diastolic cavity transverse dimensions (6-5 to 8-6 cm) however, correlation was less good (r - 0-81, mean difference = 14-3 +/- 2-3 (SEM) 5). Using the cube method, which does not allow for the changing relation between minor and major cavity axes with increasing cavity size, wall volumes were greater (76 to 986 ml) but correlation was similar (r = 0-94, mean difference = 7-1 +/- 0-9 (SEM)%). Having established that it is possible to obtain close agreement between wall volumes determined at different points in the cardiac cycle, this test can be used to assess the reliability of echocardiographic left ventricular dimensions and volume estimates in individual subjects.