My Interview With Jennifer Miller

Question: Endocarditis is an infection, but what is the growth that appears?

Answer: A platlet fibrin thrombus attaches to the endocardium and is colonized by bacteria during periods of bacteremia. The platelet fibrin thrombus forms in response to collagen exposure on a denuded endothelial surface. Proliferation of fibrin, platelets and bacteria results in the vegetative mass.
Question: Atrial Fibrillation is a heart arrhythmia, but what causes the atria to chaotically vibrate?

Answer: The atria contract chaotically because the electrical conduction system through the heart is abnormal.

Question: Can you prevent Atrial Fibrillation?

Answer:Sort of-there are certain things that are risk factors, such as administering furosemide or bicarbonate milkshakes, so by not administering these products you lower the risk of causing atrial fibrilation. (Furosemide and bicarab milkshakes are thought to be performance enhancers and are used mostly on the race track)There are other risk factors that you have no control over so in those cases you can't change much. Some of the other risk factors are valular insufficiendy and congestive heart failure.

Question: What is the treatment for Atrial Fibrillation?

Answer: The drug of choice to treat atrial fibrillation is quinidine. ~90% of horses with little or no underlying cardiac disease convert to normal sinus rhythm with quinidine therapy.

Question: What are the differences between the human heart and a horse heart?

Answer: Mainly size. We have the same basic structure and conduction system.

Question: What is platelet fibrin thrombus?

Answer: A thrombus is basically a clot and is made up of platelets and fibrin. Platelets are the smallest formed elements in the blood and fibrin is an inflammatory product. Both are part of the clotting cascade.

Question: What is proliferation?

Answer: Proliferation is the same as multiplying. It means there is more and more of the substance

Question: Why would epistaxis occur as a symptom of atrial fibrillation?

Answer: At rest, atrial fibrillation causes no change in the cardiac output unless the horse has other significant heart disease. During exercise however, atrial fibrillation causes a marked increase in the heart rate and thus cardiac output. (Cardiac output=heart rate x blood pressure.) We aren't entirely sure what causes excercised induced pulmonary hemorrhage (EIPH), but here is the current theory. When horses are exercising they have very high cardiac outputs and high capillary(the smallest of the blood vessels) pressures. If the pressure is high enough these tiny vessels rupture leading to hemorrrhage in the airways which in turn may come out the nose if the bleed if significant enough. So...EIPH can happen in an exercising horse even if they have no underlying heart disease and if you have a condition such as atrial fibrillation you increase your chance even more of having high cardiac output that puts you at risk of EIPH that then leads to epistaxis.

Question: Why would joints swell as a result of endocarditis?

Answer: The swelling is probably due to the hearts inefficient pumping capabilities.

Question: How does endocarditis effect the horses physical abilities after the disease is gone? Will the horse's heart still be as strong as it was before endocarditis?

Answer: The ability of the horse to return to work depends on the severity of the damage sustained. Many horses can go back into work successfully even though they may have some valvular insufficiency.

Question: What are some other common equine heart ailments?

Answer: Horses as a whole don't have very many heart problems. The most common ones are benign murmurs in old horses or atrial fibrillation. Congenital malformations, infectious abnormalities, or othe types of conduction problems are other things that can happen, but they are all very uncommon.