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Effect of hypoventlation on the left ventricular myocardial contractility in dogs

Zhu Guangyou, Meng Jingbi

Institute of Science and Technology, Jurisdiciton Ministry, PRC；Institute of Acupuncture, Academy of Traditional Chinese Medicine, Beijing

Abstract

Many investigations have shown that acute respiratory failure is often associated with cardiovascular dysfunction, but the underlying mechanism is obscure. The purpose of the present study is to observe the response of the left ventricular myocardial contractility to acute respiratory failure produced by hypoventilation in open-chest and anesthetized dogs. The results showed that in the experimental group (n=9) hypoventilation (minute volume<160 ml/min，Pa0_(2)<60 mmHg) caused significant decreases in heart rate (P<0.01), mean aortic pressure (P<0.05), systolic pressure and maximal rate of rise (dp/dtmax) (P<0.05), tension of regional myocardium (P<0.01) and maximal rate of rise (dT/dt_(max)) (P<0.001) but significant increases in the time to dp/dt_(max), (t-dp/dt_(max)) (P<0.05) and the time to dT/dtmaa (t-dT/dt_(max)) (P<0.O1), while in the control group (n-5) with normoventilation (minute volume>450 ml/min-kg, PaO_(2)>70 mmHg), there were no changes in aforementioned indexes during 45 minutes of experimentation. The result of the present study indicates that the left ventricular myocardial contractility is severely damaged during acute respiratory failure.

Key words: Myocardial contractility;Open-chest dogs;Hypoventilation;Acute respi ratory failure;Strain guage arch

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Citing This Article：

Zhu Guangyou, Meng Jingbi. Effect of hypoventlation on the left ventricular myocardial contractility in dogs. Acta Physiol Sin 1987; 39 (5): (in Chinese with English abstract).