Leaky heart valves
Channel: York Cardiology
Date: 2022-04-03

Leaky heart valves


Today’s video is on the subject of leaky heart valves. 

We are blessed with 4 heart valves - 2 on the left side which are known as the mitral and aortic valves and 2 on the right side - the tricuspid and pulmonary valves. Sometimes due to a congenital problem, age related changes or even an acquired cause, these valves can start leaking and when they do so to a  severe extent, they can adversely  impact on a patient’s quality of life as well as their lifespan.

The adverse impact of leaky valves is dependent on the severity of the leak as well as how quickly over a period of time that leak has developed. What I mean by this is that if a leak has slowly developed over a period of time, the heart may have time to adapt and therefore patients may not notice anything until the leak is really advanced. On the other hand, if a leak has developed very quickly then the heart may not have time to adapt and therefore the patients may become symptomatic even when the leak is not as severe.

The main problem is that leaky valves over a period of time cause a condition called volume overload meaning that with leaky heart valves, the overall blood volume that the heart has to contend with over a period of time increases.
I will explain why this happens - my explanation is probably a little oversimplified but hopefully it will help with understanding the basic concepts.

Let's say the heart hypothetically has to pump out 100 mls of blood with each heartbeat (these are just arbitrary figures) and 10% leaks back. Well now only 90 mls of blood get pumped out. And our kidneys only receive 90mls instead of 100mls. The kidneys will then behave as if the patient is dehydrated and therefore will try to absorb more water from the urine to try and increase the blood volume back to what they expect. So again very simplistically, they create another 10mls of blood. So now we have 110 mls in the system but again 10% of the 110mls leaks back and the kidneys still get less than what they were expecting and they then again try to absorb more water from the urine and produce more blood. So in essence there is a vicious cycle that develops with less blood going to the kidneys, the kidneys increasing more volume within the system and increased leaking of the heart valves. This is why this condition is known as a condition of volume overload - slowly the amount of the blood in circulation increases.

Now the problem is that the heart eventually has to contain this blood and as the amount of blood is increasing, it causes the heart to stretch. The heart behaves like a rubber band when it is stretched, When you stretch it, it twangs back with more force. If you stretch it even more, it twangs back with even greater force but if you stretch it too much then it loses its elasticity and therefore becomes weaker. So as the leak progresses, the heart responds to the volume overload by contracting with more vigour but if it is left unchecked then eventually it starts weakening and this is something you want to avoid because you may not be able to regain that strength again even after operating and correcting the valve problem.

So if you have a very leaky heart valve there are 2 main reasons to consider an operation 

If the patient is symptomatic from the leak and the symptoms are usually breathlessness, exercise intolerance and progressive swelling. The patient is breathless because he is not able to push out as much blood as the body needs because so much of it is leaking back. He is intolerant of exercise for the same reason. He swells up with swelling of the legs and the abdomen because of all this volume overload. So if the patient is symptomatic, then the valve needs fixing.

If the patient is not symptomatic but if we see that the heart is beginning to weaken then again the valve needs fixing. How can we tell that the heart is weakening? In leaky heart valves, you would expect the heart to beat with even more vigour than normal. If the heart function on an echo looks normal or even slightly less than normal then this is suggestive  that the valve needs fixing.

This is why when you have a leaky valve, the cardiologists will organise to see you at 6-12 monthly intervals where they should do 2 things:

Ask you about whether you have symptoms
Do an echo to see if your heart is looking weaker.