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Left ventricular function of the isolated, genetically obese rat's heart
The American Journal of Physiology
|April 1, 1985
Summary
Obese rats exhibit impaired left ventricular (LV) function despite increased heart mass. Their hearts show reduced systolic wall stress, suggesting dilation or depressed contractility in obese hearts.
Area of Science:
- Cardiovascular Physiology
- Obesity Research
- Animal Models
Background:
- Chronic obesity in adult animals can affect cardiac function.
- Understanding left ventricular (LV) function in obesity is crucial for cardiovascular health.
Purpose of the Study:
- To investigate whether left ventricular (LV) function is impaired in adult, chronically obese Zucker rats.
- To compare cardiac performance between obese and lean rats.
Main Methods:
- Isolated hearts from 50-week-old obese and lean female Zucker rats were metabolically supported.
- Pressure-volume (PV) relationships were measured using an intraventricular balloon.
- Ventricles were paced and hearts perfused retrogradely.
Main Results:
- Obese and lean rats had similar LV end-diastolic pressure-volume curves and chamber compliance.
- Obese rat hearts demonstrated greater pressure generation, likely due to increased LV mass.
- Peak systolic wall stress was significantly reduced in obese rat hearts compared to controls.
Conclusions:
- The hypertrophied left ventricle (LV) in obese rats may be dilated or have depressed contractility.
- Despite increased mass, obese rat hearts show diminished systolic wall stress.
- Further investigation is needed to differentiate between dilation and depressed contractility in obese hearts.