Hello and welcome to the Zero to Finals podcast.

My name is Tom and I'm going to be talking to you in this episode about Heart Murmurs.

If you want to follow along with written notes, you can find these at zero to finals.com

and click on the Learn tab.

Or you can check out the cardiology section of the zero to finals medicine

book. Now let's get straight into it. First of all, we need to talk about the normal heart sounds,

and we refer to these as S1 and S2. The first heart sound, or S1, is caused by the closing of the atrio-ventricular valves.

Now this is the tricuspid and the mitral valve. And this happens at the start of systolic contraction

of the ventricles. So as the ventricles try to push blood out of the heart, the valves between the atria and the ventricles

need to close to prevent blood from flowing back into the atria. The second heart sound,

or S2, is caused by the closing of the semi-luna valves, and this is the pulmonary and the aortic

valves. Once the systolic contraction is complete, then this is the pulmonary and the aortic valves once the systolic contraction is complete

and this is to prevent blood flowing back from the pulmonary arteries or the aorta into the

ventricles now this s1 and s2 can be heard during auscultation of the heart sounds as a

lub dub sound so let's have a listen to that now

next let's move on to a third heart sound and we call this S3.

And this is heard roughly 0.1 seconds after the second heart sound.

It's quite subtle so you can only just about hear an extra sound after the second heart sound.

Let's listen to an example. Now what causes this sound is I think of it as rapid

ventricular filling causing the cordi tendon, or the tendons inside the heart,

to pull to their full length and twang like a guitar string. This can be normal in young patients,

you know, 15 to 40 years old, because the heart functions so well that the ventricles easily

...