Welcome to episode 91 of the Audio PANCE and PANRE Physician Assistant/Associate Board Review Podcast.
Today is part one of an extraordinary five-part series with Joe Gilboy PA-C, all about cardiac murmurs.
It’s time to throw away everything you have ever learned that made you hate cardiac murmurs (you know those crazy line diagrams) and let Joe hard-wire your brain for success.
I promise you that by the end of this podcast, you will no longer be afraid of murmurs, but you will welcome them into your brain with a whole heart, open arms, and the need to share this podcast with all your classmates.
Below is a transcription of this podcast episode slightly edited for clarity.
Welcome, everybody. This is Joe Gilboy PA-C, and today is part one of a five-part series on the two most dreaded words that every pa student and recert PA hates. Are you ready for the two words?
Today we’re going to start talking about heart murmurs, and we are going to break this down into a five-part series:
We’re going to cover each valve one at a time. We will look at it and try to really make sense of it all.
Because I know what you did in PA school, you had that little diagram that you made, you know, systolic or diastolic murmurs. You’ve memorized certain things. And then you get to that test question, and you’re completely clueless on it, you’re like, “I have no idea what they just said, Joe, I have no idea.”
And then you’re back to scrambling, looking for some word that’s going to trigger you. And that’s the key point- all the trigger words, all those high-value trigger words, they’re gone. That’s what the creators of the PANCE did about two to three years ago. They took all the trigger words out.
So now, let’s look at this differently. You did it your way. How did it work out? Probably not so well. So, guess what, we’re going to do it my way. And that’s what I want to do here.
So, think about it for a second. I want you to picture the aortic valve.
Opening during systole, closing during diastole. That’s really what it’s supposed to do.
Go ahead and picture that in your head. And for those who are in a safe place, close your eyes because it makes more sense.
The valve is going to be open during systole and is going to be closed during diastole.
Now, who gets fed right after the aortic valve? Well, that’d be the coronary arteries.
If I’m lacking blood flow to my coronary arteries, how’s that feel? I’ve got chest pain.
What’s the second thing that gets fed after the aortic valve? Well, that’d be my internal and external carotid arteries.
If I lack blood flow to my internal or external carotids, how will I feel? Lightheaded with syncope and dizziness.
Where does blood flow third? That would be my left subclavian artery, and if I lack blood flow, then I get left arm pain. And then, of course, everything down south after that.
Okay, so let’s start with the first one—aortic stenosis.
So, think about this for a second. Stop memorizing. Start thinking. I have this stenotic aortic valve, and it can’t open up. So that’s my question to you. When are you going to have problems with this valve? During systole or diastole?
It is supposed to open during systole. And it won’t. It’s too stenotic.
The aortic valve is supposed to be closed during diastole, and it will close. Oh, then I see your point, then that is a systolic murmur. Right? Aortic stenosis is a systolic murmur!
Where’s the aortic valve located? The right second intercostal space. And where does it radiate to? The neck.
I want you to understand something. Who’s got to work harder to push against this stenotic aortic valve. Who’s got to work harder to open the door? It’s the left ventricle.
Okay, you’re the body. Are you going to take this, or are you going to fight back? I’m going to fight back a little bit, Joe.
So, what’s going to happen to the left ventricle? The left ventricle is going to hypertrophy.
And then go and stretch and stretch and stretch and stretch and stretch and stretch and stretch that left ventricle and you’re going to rupture the wires in there. And you’re going to get left bundle branch block.
And for those of you thinking, ahead of the game, will right ventricular hypertrophy, unopposed cause right bundle branch block? The answer is yes.
Back to aortic stenosis – I see the left ventricular hypertrophy because it’s backing up. I can even see the left bundle branch block. That makes sense.
So, aortic stenosis is a systolic ejection murmur. Oh, I see it because it’s supposed to be open during systole. But it’s a tight valve, and it won’t open up. I get it!
Let’s go one step further. It’s the most commonly acquired valvular stenosis, and usually, it’s congenital or from a bicuspid valve. But that’s not what they’re going to ask. That’s too easy. So, how would aortic stenosis present? That’s the right question.
Let’s say you have a stenotic aortic valve; it’s not opening during systole. “Hi, I have aortic stenosis, and I’m walking through Costco.”
So, you are walking through Costco, looking at the Christmas decorations or whatever they have. And how is your valve? Is it opening up? Yes, or no? No, it’s not Joe. And are you demanding more of it? You’re walking through Costco. How’s the blood flow to your coronary arteries? Oh, it’s diminished. Exactly.
Then I get chest pain with exertion – exactly. I could be walking up steps – and that’s the test question you see rear its ugly head – it’s going about the person with chest pain who’s walking up steps or exerting himself.
And then how’s your blood flow to your head? I get lightheaded and dizzy because of a lack of blood flow there. Get it? Do you see this picture?
I have this murmur in the right second intercostal space. It’s going to be systolic. The person is going to complain of chest pain and lightheadedness, and dizziness with exertion.
I can see the left ventricular hypertrophy. I can even see the left bundle branch block. Oh, that all fits.
So, they have chest pain. What do you give them? What do you give to people with chest pain? You give nitroglycerin.
And now the question is this. Well, what’s nitroglycerin? It’s a vasodilator. Where does it vasodilate? Everywhere. That’s right. I always love how people treat nitroglycerin like it’s intelligent, but it’s not. Nitroglycerin is going to vasodilate everywhere – including the left ventricle.
Wait for a second, hold on here. You just vasodilated my left ventricle, and I can’t get through the valve. Then the blood flow to my valve is not increased, but it’s decreased. And now you have less blood flow through that stenotic aortic valve. How’s your blood through the coronary arteries and in your internal and external carotids? It is incredibly diminished.
And what happens to these patients with aortic stenosis who are treated with nitroglycerine? They get syncope. See it now? It makes sense, doesn’t it?
Now, I have this systolic ejection murmur. It’s going to radiate to my neck because that’s how it’s pointing, and it’s going to be in that right second intercostal space.
And now comes the questions about inspiration, expiration, squatting, standing, and handgrip! You’re like, I just can’t believe you’re going there, Joe. Yes, we’re going there. But we’re doing it my way, which is a lot more fun.
So now let’s think about this. I want you to imagine that S1 is a date with the mitral and tricuspid valve.
So, there they are, a cute little couple, the mitral and tricuspid valve come together, and they’re the S1. And now I want you to imagine S2 as a date between the aortic and pulmonic valve – so S2 is the combination of the two sounds, and S1 is a combination of the two sounds.
Okay. Imagine I have aortic stenosis – does my valve take shorter or longer to open up? It’s taking longer to open up.
Your pulmonic valve opened on time, but your aortic valve is late to the date!
That’s right. You took longer to get ready to open up. So, guess what happens to my S2 – It becomes split.
So, you see, a split means that someone’s late to the date. Now I need more information to figure out whether it’s pulmonic stenosis or aortic stenosis.
Do you remember that ridiculous bar graph that you saw in PA school? You’re like, I have no idea what I’m looking at! What they’re trying to show you is the timing of the valves. Someone is late to the date.
So, I want you to erase what you memorized in PA school. If I have a split S2, someone’s late to the date. Is it pulmonic or aortic? I need more information, but someone’s late to the date.
Okay. One more step. Can we all agree just from a laminar flow physics point of view that the more blood flow I put across the valve, the louder it sounds?
Think about this for a second. The more blood flow I put across the valve, the louder it sounds.
So, to make aortic stenosis sound louder? What do I need to do? Put more blood flow across the valve!
Okay, so there is a party, and everybody’s showing up – Your mom, your dad, your cousins, your second cousins, the neighbors, the neighbors, friends. I mean, everybody’s showing up. Everybody’s coming back to the heart. Who’s the party maneuver? Squatting – squatting is a party!
So, what are you doing? I’m shoving all the blood flow back home. Who showed up? The entire neighborhood – and my cousins and my second cousins everybody’s showing up. So, when I squat, you know what I get? More blood flow in the heart. Guess which murmur sounds louder? All of them – mitral stenosis, mitral regurgitation, tricuspid stenosis, tricuspid regurgitation, pulmonic stenosis, pulmonic regurgitation, aortic stenosis, and aortic regurgitation – all sound louder with more blood flow back home. Who’s the maneuver? Squatting!
So, squatting really doesn’t help me much because everybody sounds louder.
And then who’s your low volume maneuvers? Who makes blood flow go away from the heart? Well, that would be standing – when you stand up, that takes blood flow away from the heart. So, all the blood flows to your legs. How are all your murmurs? They go away. So, standing is a lack of blood flow, and all the murmurs are diminished.
And then Valsalva. When you grunt, what you’re doing is Valsalva or if you have a bowel movement – what you’re doing is you’re squeezing the inferior and superior vena cava, and you’re stopping blood flow from going to the right side of the heart.
You’ve got less blood flow in the heart. So, do you have any blood flow to put on my murmurs? No, it went away. So, standing and Valsalva make murmurs go away.
Squatting sounds louder. Standing and Valsalva – these are my low volume maneuvers, and the murmur goes away.
Inspiration right. Expiration left. Inspiration right. Expiration left – and for the third time. Inspiration right expiration left – to make right-sided heart murmur sound louder, you breathe in (inspiration). What do you do to make left-sided heart murmurs sound louder? Expiration!
When you inhale, you breathe air in – imagine your inferior and superior vena cava are pushing blood into your right side. So, you get more blood flow on to the right – increasing the laminar flow on the right and increasing the sound of right heart murmurs.
When you exhale and blow air out, you are decreasing that pressure in the chest. So now the blood on the left can get out easier – increasing the laminar flow across the valve and increasing the sound of the murmur on the left.
So, one more time, inspiration right and expiration left. Hi, I’m aortic stenosis – am I on the left or the right? I’m on the left.
So, what’s it going to make it louder? Expiration!
You learned that handgrip increases peripheral vascular resistance.
Okay. Let’s translate that to more layperson terms. When I increase my peripheral vascular resistance, I’m sitting on your aortic valve. What is your only exit valve? Yes, that’s right – it’s the aortic valve. So, if I increase your peripheral vascular resistance AKA, I’m pushing all the blood against your aortic valve AKA I’m sitting on your aortic valve.
So, I want you to get this, I want this visualization of handgrip and sitting on the aortic valve. So, I’m sitting on your aortic valve, and we’re just sitting on it. Got it?
Grab your hands and squeeze them – see how your muscles are tight? Can you visualize the blood flow getting harder to come out? So, you’re pushing it against the exit valve, which is your aortic valve. And now I want you to visualize this as sitting on the valve.
Okay, hi, I’m aortic stenosis, and I can barely open up – squeak, squeak, squeak, squeak, squeak. I can barely open the valve. I’m stenotic, and you did what? You did hand grip. You just sat on my aortic valve, and I can barely open up. Do you think I can open it up anymore?
The answer is no. Exactly. So, guess what murmur is in the right second intercostal space and goes away with handgrip? Aortic stenosis!
And then, of course, how do we diagnose it? Echocardiogram!
The aortic valve is the one valve that requires an emergent replacement. So, when somebody has aortic stenosis, what is the end game? It’s going to be an aortic valve replacement.
Now, let’s discuss aortic regurgitation. Okay, with all these new tools, it’s going to be easy.
With aortic regurgitation, the valve is just flapping in the breeze, come and go as you please. I could care less – come and go as you please.
Are you going to have problems with this valve during systole? Yes, or no? No, because the valve is supposed to be open during systole.
So, when do you have problems with the regurgitating aortic valve? During diastole, when the valve is supposed to be closed!
It’s going to travel from my right-second intercostal space down to my apex.
Anything split? Is anybody late? No, not at all.
So, aortic regurgitation will be a diastolic murmur, and there is a wide arterial pulse pressure. They call this a water-hammer pulse. To understand this, imagine your pulse as a series of train cars. So, imagine a train, and there’s your aortic valve—pulse, pulse, pulse, pulse, pulse, pulse, pulse. But imagine if you’ve got aortic regurgitation – What do you do?
Well, I threw a pulse out there. But did you hold it out there? No, because my valve was open. So, what happened to some of that blood that you threw out there? It sneaks back home!
They call that wide arterial pulse pressure. I want you to view the arteries like this PVC pipe. You threw blood out there, didn’t you? So, it kept it full. But during diastole, I didn’t close the door. So, it all rushed back home, and the pipe collapsed. Exactly. That’s what we call a wide arterial pulse pressure, and this is what’s called a water hammer pulse.
So, I have this diastolic murmur. Right second intercostal space. Radiates to the apex. Okay. Let’s make it sound louder. What do you want to do? Oh, let’s squat – that’s a party!
To make it go away. I could stand or Valsalva. These are my low-volume maneuvers. Does inspiration or expiration make it louder? This is on the left, so expiration makes it louder.
So, I’m sitting on your aorta valve, and what’s the problem? You can come and go as you please. So, what will happen when we perform handgrip with aortic regurgitation is that blood flow is going to go against your valve, and it’s wide open. Blood is going to go right through it!
So now, does everybody see this question rearing its ugly head?
Instead of going for the knee-jerk answers that you’ve memorized (I call this the data closet in a student’s head), try to make sense of the question instead of going for your data closet. Think laminar flow physics.
And now, do you see the test question? They’re not going to tell you if it’s systolic or diastolic. That’s too easy. They’re going to tell you about some murmur in the right second intercostal space that either gets louder with handgrip (aortic regurgitation) or goes away with handgrip (aortic stenosis).
And now you will get the answer right every time!
Now go back and re-listen to this podcast episode a couple of times. I always tell people if they get a chance to listen to this podcast, do yourself a favor and find a quiet room and turn off all the lights.
And then just listen. Keep your eyes closed and visualize this in your head… and that’s just money!
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Photo Credit: Bruce Blaus, CC BY 3.0 https://creativecommons.org/licenses/by/3.0, via Wikimedia Commons