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Questions and Answers
What is the primary characteristic of acute heart failure?
What is the primary characteristic of acute heart failure?
Which of the following is a cause of primary dysfunction of myocardial systole and diastole?
Which of the following is a cause of primary dysfunction of myocardial systole and diastole?
What method is used to induce acute heart failure during the experiment?
What method is used to induce acute heart failure during the experiment?
Which action is a part of cardiac compensation during acute heart failure?
Which action is a part of cardiac compensation during acute heart failure?
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What type of overload contributes to acute heart failure through chronic anemia?
What type of overload contributes to acute heart failure through chronic anemia?
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What is one manifestation of myocardial ischemia due to coronary artery disease?
What is one manifestation of myocardial ischemia due to coronary artery disease?
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Which physiological change occurs as part of extracardiac compensation during acute cardiac failure?
Which physiological change occurs as part of extracardiac compensation during acute cardiac failure?
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What is the procedure to measure blood pressure during the experiment?
What is the procedure to measure blood pressure during the experiment?
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Study Notes
Acute Cardiac Failure in Rabbits
- The purpose of the experiment is to replicate experimental acute right heart failure and understand the manifestations and mechanisms of cardiac failure.
- Acute heart failure is characterized by a rapid onset and sharp decrease in cardiac output in a short period.
Causes of Cardiac Insufficiency
-
Primary myocardial dysfunction:
- Myocarditis
- Myocardiopathy
- Myocardial necrosis, fibrosis
- Myocardial ischemia caused by coronary artery disease or vitamin B₁ deficiency
- Dysfunction of myocardial systole and diastole
-
Cardiac overload:
- Volume overload: mitral or aortic insufficiency, chronic anemia, hyperthyroidism
- Pressure overload: systemic hypertension, pulmonary hypertension
- Restricted cardiac filling: Constrictive pericarditis (inflammation of the pericardium)
Mechanisms of Cardiac Compensation
-
Cardiac compensation: The body may try to compensate and restore blood supply in tissues and organs; Mechanisms include:
- Increased heart rate
- Positive inotropic actions of catecholamines
- Cardiac ontogenic dilation
- Myocardial hypertrophy
Mechanisms of Extracardiac Compensation
-
Extracardiac compensation: Mechanisms include:
- Increased blood volume
- Redistributed blood flow
- Erythrocytosis
- Increased tissue capability to utilize oxygen
Experimental Methods
- Pressure Overload: Injecting liquid paraffin to induce thromboembolism
- Volume Overload: Injecting normal saline into the heart via the ductus venosus
- Anesthesia: Inject 30% urethane from marginal ear vein, at 3.3ml/kg
-
Surgical Procedure:
- Weigh Rabbit
- Anesthetize and fix on operating table
- Incise skin along cervical midline, to expose the area and make it accessible for surgical procedures.
- Separate Left Common Carotid Artery and insert arterial cannula to measure blood pressure
- Separate Right Vena Jugularis Externa and insert venous cannula to measure cardiac venous pressure (CVP)
- Inject heparin to prevent blood clotting immediately before using the cannula
- Inject normal saline into the heart
- Observe blood pressure, CVP, heart function, liver, and ascites
Results
- The expected results to be observed are
- Blood pressure
- CVP
- Heart
- Liver
- Ascites
Questions
- Compensation mechanisms in the rabbit: Increased heart rate, positive inotropic actions of catecholamines, cardiac ontogenic dilation, myocardial hypertrophy
- Causes of heart failure: Pressure overload and volume overload
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Description
This quiz explores the mechanisms and manifestations of acute cardiac failure, particularly in rabbits. It delves into causes of cardiac insufficiency and the body's compensatory responses to restore function. Test your understanding of this critical subject in cardiovascular physiology.
