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Modeling of asynchronous myocardial contraction by effective stroke volume analysis
1Cardiopulmonary Research Laboratory, Department of Anesthesiology and Critical Care Medicine, University of Pittsburgh, PA, USA. dpstrum@life.uams.edu
Anesthesia and Analgesia
|January 29, 2000
Summary
Quantifying regional wall motion abnormalities (RWMA) is challenging. A new model using phase angle analysis proved more sensitive for detecting myocardial dysfunction than traditional methods in dogs.
Area of Science:
- Cardiovascular Physiology
- Myocardial Mechanics
- Echocardiography and Imaging
Background:
- Quantifying left ventricular (LV) regional wall motion abnormalities (RWMA) presents significant challenges in clinical practice.
- Traditional methods may not adequately capture subtle regional myocardial dysfunction.
Purpose of the Study:
- To develop and validate a novel model for quantifying RWMA.
- To assess the sensitivity of phase angle analysis and effective stroke volume (SV) in detecting regional myocardial dysfunction.
Main Methods:
- A canine model with esmolol-induced apical RWMA was used.
- LV volumes, regional shortening, and LV pressure were measured.
- A new model defined regional phase angle (alpha) relative to global LV systole.
- Maximal and effective SV were compared.
Main Results:
- Esmolol significantly delayed apical end-systolic phase angle (alpha).
- Apical effective SV decreased significantly, while maximal SV and total LV SV remained unchanged.
- Regional SV changes correlated with piezoelectric crystal dimension changes.
Conclusions:
- Phase angle analysis and effective SV are more sensitive indicators of regional myocardial dysfunction during RWMA.
- This model offers improved quantification of regional myocardial performance in the presence of dyskinesis.