Welcome to episode 92 of the Audio PANCE and PANRE physician assistant/associate board review podcast.

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Today is part two of this extraordinary five-part series with Joe Gilboy PA-C, all about cardiac murmurs. In this week’s episode of the Audio PANCE and PANRE podcast, we continue our discussion of cardiac murmurs with a focus on the mitral valve.

We’ll talk about the different types of murmurs (stenosis and regurgitation) that can occur with this valve and how to differentiate them from other types of murmurs. If you haven’t already, make sure to listen to our previous podcast episode where we covered the aortic valve murmurs.

The Mitral Valve

The mitral valve is located between the left atrium and the left ventricle in the heart. It consists of two leaflets (or cusps) and is responsible for preventing blood from flowing back into the atrium when the ventricle contracts.

The mitral valve can have two types of murmurs: stenosis and regurgitation.

• Mitral stenosis is a narrowing (or constriction) of the valve opening, which reduces the amount of blood that can flow through the valve. This type of murmur is of low pitch, rumbling in character, and best heard at the apex with the patient in the left lateral position.
• Mitral regurgitation is a leakage (or backflow) of blood from the ventricle into the atrium, caused by weakened or damaged valve leaflets. This type of murmur is a holosystolic (pansystolic) murmur, heard best at the apex with the diaphragm of the stethoscope when the patient is in the left lateral decubitus position.

In addition to auscultation, you can also look for certain signs and symptoms that may indicate mitral stenosis or regurgitation. For example, if a patient presents with chest pain (angina pectoris), this could be from decreased oxygen supply due to poor cardiac output in cases of significant stenosis. On the other hand, if a patient presents with an irregular heart rate (arrhythmia), this could be from increased electrical conduction velocity in cases of significant regurgitation.

Also, keep in mind that mitral valve disease can also occur secondary to rheumatic fever or endocarditis, so you may need to consider these diagnoses if a patient has any of the aforementioned signs and symptoms.

Below is a transcription of this podcast episode edited for clarity.

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Welcome, everybody. This is Joe Gilboy, and I work with Stephen Pasquini at Smarty PANCE.

Today we’re back to the heart murmur podcast, and we just finished the aortic valve. The next one up is the mitral valve.

Let’s just look at this my way. In school, you memorize a bunch of facts, then someone asks a question about mitral stenosis or mitral regurgitation, and you are completely lost. It’s time to change that. Now, we are going to do it my way. Are you ready? Here we go.

Let’s look at the mitral valve on a normal day. What’s the mitral valve doing?

• There is my left atria. It’s contracting during diastole, my mitral valve opens up, and the blood flow goes to the left ventricle.
• Then during systole, the mitral valve will close, the left ventricle will squeeze, and the aortic valve opens.

Mitral Valve Stenosis

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Let’s start with the first heart murmur, mitral stenosis. Think about it. Slow down and give this some thought.

I’ve got the stenotic mitral valve. See it? It can barely open. It’s like, man; you’ve got to push hard to open this door. So, you are the left atrium, and you’re pushing down on this stenotic mitral valve. It’s like, man; this is hard to open up! I have to push harder. Yes, you do!

Wait for a second; then I’m going to put more blood flow back against my left atrium? Completely correct. So, my left atrium might hypertrophy? Yes, that’s correct!

So, you’re telling me I might get left atrial hypertrophy with mitral stenosis? Exactly!

Now, think about it. There you are in the left atrium pushing against the mitral valve during stenosis that’s supposed to open during diastole. You’re just taking longer to open up. You see, in school, what you memorize is an opening snap. Remember that ridiculous graph where you saw it had S1, S2 on all those bar graphs? You thought you were reading a musical sheet. Do you remember that thing? Or you’re like oh, S1 S2 ……….!? You were looking at it thinking, ” I have no fricking idea what I’m looking at.” Let’s erase that.

Think about this for a second; if the left atrium is pushing on a stenotic valve, it’s going to have trouble during diastole. Because during systole, it has to be closed. It’s going to close without a problem.  The problem is opening it up. You can see the left atrium hypertrophy. Then blood flow may back up into the lungs and causes pulmonary hypertension.

Oh, wait for a second, I get pulmonary hypertension? Yes, you do!

Then maybe I have some fluid backed up in the lungs, and I might have a little shortness of breath and CHF. Exactly! Yes, that’s exactly how they’re going to present.

So, I have this diastolic murmur. It’s a diastolic ejection murmur to open that valve up. So, it’s not going to be an accentuated S1. But that’s not what they’re going to say on your boards, are they? No, that’s just a buzzword.

What they’re going to say is, “I have this diastolic rumbling murmur.” Rumbling means I’m trying to open up, and I’m going to radiate down towards the apex. That just makes logical sense.

So, I have this diastolic murmur radiating to the apex. Let’s take a closer look at the mitral valve. Remember, your heart doesn’t sit flat. It sits tilted and towards the back. So, I need this mitral valve to get towards the front. Okay, well, then tilt yourself to the left and lay down. Oh! That’s that left lateral to decubitus position they keep talking about. I’m going to bring it closer to the front.

Oh, that makes sense. I totally see that. So, I have a diastolic murmur that radiates to the apex. I can hear it better if I lay down on the left lateral decubitus position because that will bring the valve closer to the chest. Let’s make it sound louder now.

Okay, one more time back to how we were in the beginning with <a href="https://smartypance