Heart Sounds – Advanced Assessment

00:01 Alright, so now we're going to jump into a discussion of the cardiovascular exam.

00:05 I should preface right off the bat that this is not intended to be a comprehensive course on the assessment of the heart.

00:11 A person could spend hours, days, weeks going over all the different kinds of manifestations of cardiovascular disease, the different kinds of murmurs that can appear, the different maneuvers you can do to elicit or suppress certain murmurs and cardiac findings, not to mention the entire wealth of findings there may be in pediatric or congenital cardiac malformations, which I am not going into in this course.

00:36 Instead, my intention is to make sure that we have a good foundation on the common murmurs that you're going to find at the bedside, and a list of a few of the common maneuvers that you can do to really accentuate those murmurs.

00:51 But first off, the cardiac exam always starts when you walk in the room, long before you start putting this on your patient, and essentially when you look at your patient and decide whether or not they really are in distress.

01:03 You know, a patient is complaining of chest pain could just be from some sort of musculoskeletal injury and they could be quite comfortable sitting there and not have any other evidence of any systemic or cardiovascular badness happening at the time.

01:16 In contrast, a person who's in acute coronary syndrome, it shouldn't be that subtle, if they have a significant coronary event happening.

01:25 They may have diaphoresis on their forehead with evidence of just sweating.

01:29 They may look really anxious and uncomfortable.

01:32 Certainly, they may be in respiratory distress, which we'll talk a little bit more about in the pulmonary section.

01:37 And hey, they may even be clutching their chest right before your eyes as evidence of the source of this crushing chest pain that they're experiencing.

01:45 So having done that our patient, at least at the moment, looks fairly calm, doesn't look like he's having a lot of anxiety, is not clutching his chest, and he's not diaphoretic.

01:53 So that's a good sign, we can take our time by examining this patient.

01:57 With that, let's talk about the cardiovascular exam.

02:01 So when you know the cardiac exam, many things are possible.

02:06 Now, what do I mean by that? Many things are possible is actually not just a statement of fact, it's also an acronym.

02:13 It's a useful way to remember the heart valves.

02:17 Many Things Are Possible is M-T-A-P.

02:20 Let me just draw that here.

02:23 M T A P.

02:32 Those letters represent the sequence of closing of the four heart valves in the heart, the mitral, the tricuspid, the aortic and the pulmonic.

02:43 And using that acronym, many things are possible.

02:45 You'll remember which sequence those valves are closing.

02:48 You'll also remember where they're located.

02:50 This is a circle, M-T-A-P.

02:52 M-T-A-P, which helps us to keep track of where we are when we're listening for particular murmurs and trying to find the etiology of a particular murmur that we hear based on the location on the anterior chest wall.

03:07 The next thing to talk about is once we lay our stethoscopes on his chest, we're going to be listening in particular to three phases of the cardiac cycle.

03:17 You're going to listen first to heart sounds, that is your S1 and S2, also known as your "lub-dub, lub-dub, lub-dub".

03:24 We're going to listen to the S3 and S4 parts of the heart sounds.

03:27 Those are your gallops, which can accompany your "lub-dub and lub-dub".

03:31 The second part is systole.

03:33 So we're going to focus very deliberately on listening to the space between S1 and S2.

03:38 And then we're going to listen to diastole, the space between S2 and S1.

03:43 And I found that really important when you're auscultating the chest to make sure you really very deliberately listen to one thing at a time.

03:50 First, the heart sounds, then systole then diastole.

03:56 That helps you to avoid the common mistake of getting so sucked into a very loud systolic murmur that you neglect to hear that more subtle diastolic murmur that's happening afterwards.

04:08 So with that, opening outline, heart sounds, systole, diastole, let's start off by talking about the heart sounds.

04:14 So S1 and S2, "lub-dub lub-dub", as we said before, many things are possible so M and T are the first heart sounds, so that must represent S1, and then A-P represent the second heart sound, S2.

04:30 These are paired together because they're so closely occurring in space, all we hear is a "lub", not two different sounds just the "lub", and then the "dub" is the A and the P.

04:41 Importantly, the S1 and S2 heart sounds are higher in pitch than some other sounds that you might hear.

04:47 And this leads me to our important quick brief on your stethoscope.

04:52 The stethoscope has two heads on it, you've got a bell, you've got a diaphragm.

04:57 These are useful in different circumstances.

05:00 In particular, the bell of your stethoscope is most useful for low-pitched sounds.

05:05 It actually, by putting the bell on the chest and creating a seal, you are filtering out a lot of the higher pitched sounds.

05:12 In contrast, the diaphragm is useful for hearing all of the different pitches within the heart, though with potentially a little bit of a focus on some of the higher pitched sounds.

05:21 So when you're using the diaphragm - you're thinking higher pitch, the bell - you're thinking lower pitch.

05:26 So I just said that the S1 and S2 heart sounds, we know that there, we're going to best hear S2 up here, we're going to best hear S1 down here.

05:36 And typically you're listening with the diaphragm because they're both higher pitch sounds, like so.

06:09 Now in some patients, you may find that rather than just hearing this simple "lub-dub, lub-dub, lub-dub", maybe you hear an extra sound, something like the "buh-lub-dub, buh-lub-dub, buh-lub-dub".

06:22 That is an extra heart sound, in this case a "buh" occurring before the "lub" and that's called an S4.

06:29 It immediately proceeds systole and it's called a fourth heart sound.

06:34 It's part of the atrial kick.

06:37 What's happening when you hear an S4 is that the left ventricle has fully filled during diastole, you have diastolic filling, and at the end of diastole, the left atrium is contracting and spitting out that last volume of blood from the atrium, but it's hitting against a stiff left ventricular wall.

06:57 And this is something that you'll hear in patients with left ventricular hypertrophy, potentially hypertrophic obstructive cardiomyopathy.

07:05 And it's a very characteristic feature that you'll find in a lot of folks, and it does portend or suggest that a patient does have one of those conditions.

07:14 Importantly, that "buh-lub-dub", the "buh" is a lower pitched sound.

07:19 And as I said before, that means you're going to best catch it with the bell of your stethoscope.

07:24 Before we find it, though, let's just quickly talk about the other kind of abnormal gallop that you might hear.

07:30 Rather than "lub-dub, lub-dub lub-dub", you might hear a lub-duh-bub, lub-duh-bub, lub-duh-bub, lub-duh-bub, essentially, that is a sound happening right after S2.

07:45 So rather than "lub-dub", it's "lub-duh-bub, lub-duh-bub".

07:48 And you can tell that that "bub" is coming right after the "duh", which would have been a "dub", and that is an indication of an S3, a third heart sound.

07:59 Now our third heart sound is also emanating from the left ventricle down here at the apex of the heart.

08:05 And rather than being associated with left ventricular hypertrophy, it's typically found in acute systolic heart failure, with left ventricular dilation, potentially increased filling pressures and almost always some evidence of systolic heart failure, whether it's in the setting of ischemic cardiomyopathy, or potentially if somebody has aortic regurgitation with a surplus of blood backfilling into the heart, then has to be ejected.

08:30 So that sound is also heard at the apex, which is where of course the left ventricle is going to be best heard.

08:36 And it's also a low pitch sound just like the S4.

08:41 So the ideal way to bring about that sound, it's going to be with the bell.

08:46 And since we really want to try and accentuate that sound, because it can be very subtle to hear We're also going to reposition our patient and lie him in the left lateral decubitus position to really bring out that heart sound.

08:59 Alright, so now that we have Shawn in the left lateral decubitus position, this is the ideal place for us to try to pick up a third or fourth heart sound.

09:11 I've got the bell of my stethoscope lightly applied to his chest, simply to provide a seal if I push too hard, I'm actually just creating a diaphragm out of the skin.

09:22 So you just want to have light pressure at the apex and that's it.

09:33 Now, there's a couple different positions that you may see over the course of this next few minutes.

09:39 Depending upon what you're looking for, you may have him lying in the left lateral decubitus position, you may have him sitting upright, you may have him lying flat.

09:47 In general, you don't want to have to repeat the entire cardiac exam in all three positions.

09:52 So as we go through each murmur, each type of valvular disease, I'll talk about which positions may be most appropriate.