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Characterizing ventricular mechanics and energetics following repeated coronary microembolization
K Todaka1, D Leibowitz, S Homma
1Division of Circulatory Physiology, College of Physicians and Surgeons, Columbia University, New York, New York 10032, USA.
The American Journal of Physiology
|January 1, 1997
Summary
Chronic heart failure (CHF) in dogs, induced by microembolizations, shows depressed cardiac function but preserved myocardial properties. Energetics reveal altered oxygen consumption related to pressure-volume area in this heart failure model.
Area of Science:
- Cardiovascular Physiology
- Heart Failure Pathophysiology
- Myocardial Mechanics and Energetics
Background:
- Chronic heart failure (CHF) models are crucial for understanding disease mechanisms.
- Investigating myocardial mechanics and energetics provides insights into cardiac function.
- Coronary microembolization offers a distinct etiology for inducing heart failure.
Purpose of the Study:
- To characterize myocardial mechanics and energetics in a canine model of chronic heart failure (CHF) induced by coronary microembolizations.
- To compare ventricular properties and energy utilization between embolized and normal hearts.
- To differentiate this CHF model from others, such as pacing-induced heart failure.
Main Methods:
- Created a moderate chronic heart failure (CHF) model in six dogs via repeated coronary microembolizations.
- Isolated and cross-perfused hearts, with balloons placed in the left ventricle (LV) for pressure-volume analysis.
- Assessed chamber contractile state using end-systolic pressure-volume relations and analyzed myocardial stress-strain relationships and oxygen consumption relative to pressure-volume area.
Main Results:
- Embolized hearts exhibited markedly depressed chamber contractile state (reduced Ees slope and altered V intercept) and LV dilation (right-shifted end-diastolic pressure-volume relation).
- Systolic and diastolic stress-strain relationships were similar between embolized and normal hearts, indicating preserved average myocardial properties.
- The relationship between oxygen consumption and pressure-volume area showed a smaller intercept in embolized hearts, suggesting altered energetic efficiency.
Conclusions:
- This coronary microembolization model results in moderate chronic heart failure with depressed overall ventricular function but preserved intrinsic myocardial properties.
- Energetic efficiency, specifically oxygen consumption relative to pressure-volume area, is altered in this CHF model.
- These findings characterize a unique CHF model distinct from pacing-induced heart failure, offering valuable insights into different heart failure etiologies.