This question is pertaining to Anatomy and Physiology

Question

1) One potential cause of valve dysfunction is rupture of the chordae tendineae. Why would this lead to valve dysfunction? Would this affect the atrioventricular valves, the semilunar valves, or both? Explain.

Answer 1

To answer this question, you need to have a good grasp of cardiac anatomy and physiology. Which cardiac valves have chordae tendinae and what is the function of these structures? If their function is to promote forward flow of blood through the heart, and prevent backflow, the effect will be the result of failure of these valves to perform this function. Failure to keep blood moving in the right direction will have what effect on cardiac output and tissue perfusion? What signs and symptoms would develop as a result?

Answer 2

A valve, by definition, allows flow only in one direction. The chordae tendinae ensure that the valve leaflets can only open in that one direction. If the chordae tendinae are ruptured, the valve leaflet will swing open in both directions, thereby allowing flow in both directions as well. The affected valve will no longer be able to keep the blood flowing only in a forward direction.

Since the blood is no longer flowing only in one direction through the heart (i.e., it is now flowing both forward and backward, depending on whether the heart is contracting or relaxing), a significant portion of the blood will likely go nowhere. It will simply pass back and forth through the valve, and not move forward. This will reduce the amount of blood coming out of the heart (i.e., the cardiac output), and therefore the amount of blood reaching the tissues (i.e., tissue perfusion). Signs and symptoms of inadequate tissue perfusion include all of the signs and symptoms of shock, since shock, by definition, is inadequate tissue perfusion:

1. Cold, pale skin; possibly sweating
2. A weak, rapid pulse
3. Shallow, rapid breathing
4. Low blood pressure (a later sign, seen in more severe cases)
5. Altered mental status (dizziness, light-headedness, confusion, anxiety, lethargy)
6. Thirst
7. Low urine output
8. Nausea or vomiting, especially if the digestive tract is affected

These are generally signs that the body is attempting to compensate for what it perceives as possible blood loss. This makes sense, since the body is noticing that the tissues are not getting enough blood (i.e., inadequate tissue perfusion), and assumes that this is because it has lost a significant amount of blood).

Since only the atrioventricular valves (i.e., the mitral and tricuspid valves) have chordae tendinae, they are the only valves that will be affected by a rupture of the chordae tendinae.

What to do if you see these symptoms? This is a medical emergency.

1. Call an ambulance if needed, and get them to the hospital right away.
2. Let them lie down, and cover them with a blanket to keep them warm.
3. Do not give them anything to eat or drink, as that could cause problems with anesthesia if it is needed, and worsen the problem faced by the digestive tract by increasing the demand for blood flow at the worst possible time.