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Regional circumferential lengthening patterns in canine left ventricle
The American Journal of Physiology
|November 1, 1983
Summary
This study reveals regional differences in how the left ventricle lengthens during diastole. Ventricular filling patterns vary across the base, mid, and apex, influenced by pressure and elastic recoil.
Area of Science:
- Cardiovascular Physiology
- Cardiac Mechanics
Background:
- The left ventricle's diastolic function is crucial for effective cardiac filling.
- Regional variations in myocardial properties may influence diastolic mechanics.
Purpose of the Study:
- To investigate regional differences in myocardial lengthening during diastole.
- To examine the impact of left ventricular diastolic pressure (LVDP) on these patterns.
Main Methods:
- Sonomicrometers were used in open-chest dogs to measure myocardial segment lengthening.
- Left ventricular pressure was manipulated via vena caval occlusion and volume expansion.
Main Results:
- Lengthening occurred at different times across the base, mid, and apex of the left ventricle.
- Peak lengthening rates were highest at the apex at low LVDPs, with regional differences diminishing as LVDP increased.
- The base showed significant lengthening during the slow diastolic phase, unlike the apex.
Conclusions:
- Significant regional variations exist in the timing of diastolic phases and myocardial lengthening patterns within the left ventricle.
- Volume-dependent changes in lengthening rates suggest regional differences in elastic recoil, potentially contributing to active ventricular filling.