| Autor: |
Takahiko, Kiyooka, Yu, Oshima, Waso, Fujinaka, Gentaro, Iribe, Satoshi, Mohri, Juichiro, Shimizu |
| Rok vydání: |
2014 |
| Předmět: |
|
| Zdroj: |
The Tokai journal of experimental and clinical medicine. 39(1) |
| ISSN: |
2185-2243 |
| Popis: |
Although tachycardia is well known to increase cardiac oxygen consumption (Vo2) per min, the relationship between Vo2 for excitation-contraction (E-C) coupling per beat and heart rate change over its full working range still remains controversial.To elucidate this relationship, we varied heart rate over a reasonably wide range (60-180 beat/min) and studied the relationship between left ventricular (LV) Emax (load-independent contractility index), PVA (pressure-volume area)-independent Vo2, and basal metabolic Vo2 in nine excised, cross-circulated canine hearts.PVA-independent Vo2 per min significantly increased linearly with increasing heart rate while Emax remained unchanged. Basal metabolic Vo2 per min was measured under KCl arrest. E-C coupling Vo2 per min obtained by subtracting the constant basal metabolic Vo2 from the PVA-independent Vo2 also significantly increased linearly with increasing heart rate. However, PVA-independent Vo2 per beat significantly decreased with increasing heart rate. In contrast, E-C coupling Vo2 per beat, as well as that normalized to Emax, slightly but significantly increased with increasing heart rate.The E-C coupling energy for myocardial Ca2+ handling increases with heart rate despite constant contractility in the left ventricle of the excised cross-circulated canine heart. |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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