Treatment of tricuspid valve insufficiency may not be necessary in asymptomatic individuals. If treatment is required the administration of vasodilators, anti-arrhythmia drugs, diuretics and anticoagulants may improve the horse’s condition.
Pulmonary Valve Insufficiency
Pulmonary valve insufficiency describes the dysfunction of the semilunar valve located between the right ventricle and the _____________________ . This valve normally functions to prevent blood from flowing back into the right ventricle from the pulmonary artery. Infection, fever or parasitic damage can lead to the fibrosis of the valve flaps causing incomplete closure of the pulmonary valve. Congenital defects may also result in incomplete closure of the valve. Failure of the pulmonary semilunar valve to close causes blood to regurgitate back into the right ventricle after it has been ejected into the pulmonary artery. This causes the right ventricle to begin filing from the pulmonary artery before the tricuspid valve opens and normal filling from the right atrium begins. Blood leaving the pulmonary artery both back into the right ventricle and distally towards the lungs causes a decrease in pulmonary diastolic pressure. The increase in fill and pressure in the right ventricle causes the ventricle to contract more forcefully resulting in an increase in ventricular and pulmonary systolic pressure, and an increase in the total stroke volume. Chronic pulmonary valve failure leads to cardiac congestion, ________________ & dilation of the right ventricle and right atrium. Pulmonary valve insufficiency is often asymptomatic, and clinical signs are general when they are present. Clinical signs and symptoms include exercise intolerance, heart murmur and systemic edema. EKG reveals enlargement of the right atrium and the right ventricle.
Diagnosis of pulmonary valve insufficiency is made through auscultation and EKG.
Treatment of pulmonary valve insufficiency may not be necessary in asymptomatic individuals. If treatment is required, the administration of vasodilators, anti-arrhythmia drugs, diuretics and anticoagulants may improve the horse’s condition.
Acute Heart Failure
Acute heart failure is caused by cardiac ___________________ .
The migration of _________________ larvae through the blood vessels results in damage to the vessel walls. This causes clotting in the vessels at the sites of damage. If larvae migrate into the coronary arteries, the arteries feeding the heart muscle, blood clots can form in these arteries resulting in ___________________ of the vessels and ischemic necrosis of the myocardium.
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