Effects of physical training on end-diastolic volume and myocardial performance of isolated rat hearts
| Autor: | J Scheuer, M M Bersohn |
|---|---|
| Rok vydání: | 1977 |
| Předmět: |
Male
Cardiac function curve Cardiac output medicine.medical_specialty Physiology Heart Ventricles Atrial Pressure Oxygen Consumption Coronary Circulation Physical Conditioning Animal Internal medicine Heart rate medicine Animals Cardiac Output Aorta Swimming Ejection fraction Chemistry Dye Dilution Technique Isoproterenol Mean Aortic Pressure Heart Organ Size Myocardial Contraction Propranolol Rats Volume (thermodynamics) cardiovascular system Cardiology End-diastolic volume Rheology Cardiology and Cardiovascular Medicine |
| Zdroj: | Circulation Research. 40:510-516 |
| ISSN: | 1524-4571 0009-7330 |
| Popis: | We studied the performance of ventricular muscle and cardiac function of hearts from rats conditioned by swimming (CH) and from sedentary rats (SH) in an isolated working heart apparatus modified to measure end-diastolic volume by dye dilution. Instantaneous aortic flow, left ventricular (LV) pressure and oxygen consumption were measured. Heart rate and mean aortic pressure were kept constant, and atrial filling pressure was varied from 5 to 20 cm H2O. Heart weights of SH and CH were equal and end-diastolic pressures and volumes were similar at all atrial pressures. However, ejection fraction, calculated circumferential fiber velocity, peak systolic pressure, peak aortic flow, cardiac output, and stroke work were all greater in CH than in SH, and the differences increased as atrial pressure was increased. Maximal negative dP/dt was greater in CH than SH at all preloads (P less than 0.001). Oxygen consumption of CH was increased in proportion to the increase in work. These results indicate that the improved pumping performance of CH is due to a change in ventricular muscle function. Faster relaxation is a prominent effect of physical training on the rat heart and may foster more complete filling at high heart rates. |
| Databáze: | OpenAIRE |
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