Diastolic Murmurs – Advanced Assessment

by Stephen Holt, MD, MS

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    00:01 So, as I just said diastolic murmurs are always worth investigating.

    00:05 And the two ones we're going to look at are aortic regurgitation or also known as aortic insufficiency, and mitral stenosis.

    00:12 Aortic insufficiency is a remarkable cardiac valve problem that has a variety of different manifestations with dozens of different eponymous findings that have been described.

    00:25 I'm really gonna focus on some of the cardinal features of aortic regurgitation.

    00:29 And let's start off with my little acronym, LISP-T.

    00:33 So, location.

    00:34 The best place to listen for aortic regurgitation is going to be in the tricuspid area.

    00:37 It's actually somewhat between the pulmonic and tricuspid areas.

    00:41 While you're here, this diastolic murmur.

    00:44 Intensity, this is a soft murmur.

    00:47 And that's why going back to the beginning of this lecture, I talked about the importance of listening deliberately to the heart sounds, to systole and diastole.

    00:56 Many is the case where I've been with a resident or student who speaks volumes about the systolic murmur that they heard, but they completely neglect to pick up the diastolic murmur because they were so focused on just hearing the systolic murmur.

    01:10 So it's very important to really focus on that period between S2 and S1, which is so often neglected.

    01:16 So the intensity of this murmur is going to be quiet.

    01:22 Certainly the more intense it is, the more that does correlate with the severity of the insufficiency.

    01:27 Shape and Pitch.

    01:29 So, this is also a high pitched sound.

    01:32 It tends to be decrescendo, purely decrescendo.

    01:35 The classic onomatopoeia phrasing for this one is...

    01:43 So, it's starting off relatively high, maybe a little bit in early peak and then going down again.

    01:53 But it's going to be a lot softer. It's very subtle, you really have to pay attention to find it.

    01:57 The pitch is high.

    01:59 And then in terms of the timing, it tends to occur immediately as diastole is beginning.

    02:06 Because remember, when the left ventricle contracts, it immediately closes and the mitral valve and tricuspid valve, that's S1.

    02:14 And then as soon as the aortic valve closes, which is the beginning of S2, It's not fully closing, what's happening is that blood is now starting to regurgitate back into the left ventricle.

    02:26 That's the cardinal feature that were going to deficiency is blood going backwards.

    02:30 So there's this constant to and fro, to and fro motion to aortic regurgitation.

    02:38 It tends to not radiate though sometimes you can hear what's called an Austin Flint murmur here at the apex, which is the sound of that regurgitant jet of blood hitting the left ventricular apex.

    02:50 The other important features about aortic regurgitation are starting with the pulse pressure.

    02:56 So when the left ventricle contracts, that's what maintains your systolic blood pressure.

    03:01 Blood contracts, there's this huge surge of blood out into my extremities where someone's got a blood pressure cuff on and you detect that korotkoff knocking sound of blood shooting past or shooting underneath my blood pressure cuff.

    03:14 That's the systolic impulse itself.

    03:16 But of course, from one systolic impulse to the next, it's not as if our blood pressure collapses, right? There's our diastolic pressure.

    03:25 There's this pressure that's maintained during the space between those systolic contractions, that's your diastolic pressure.

    03:33 And the thing that maintains that pressure, such that we aren't just constantly losing consciousness between every beat of our heart is the fact that our aorta has recoil.

    03:42 When blood shoots through the aorta, it dilates, the valves close, and then the aorta has elastic recoil that then constricts around that huge jet of blood, which then is maintaining the pressure downstream during diastole.

    03:58 The trouble is that once systole happens, and the valve closes, when the aortic arch recoils, if the valve holding it together is not functioning, the aorta recoils and blood is going now backwards back into the heart.

    04:15 Any valve system requires valves that close tightly.

    04:18 And if the aortic valve is not closing tightly, bloods going to go in both ways.

    04:22 Some of it will go forward, but a lot of it's going backward.

    04:25 Because of that, we find a very clear manifestation of that simply by checking somebody's blood pressure.

    04:31 You'll have a high systole and a very low diastole.

    04:34 That's called your pulse pressure.

    04:36 It's the difference between your systolic blood pressure and your diastolic blood pressure.

    04:40 So let's say that our patient, for example here had a blood pressure of 130/50.

    04:45 So, 130 being the systolic, 50 being the diastolic.

    04:48 It's the difference between them that tells us, what the pulse pressure is? And again, that's that concept of the 130 is your, what happening in your systole which is your left ventricular impulse, And the 50 is your diastolic pressure being maintained by that aortic recoil with a competent aortic valve.

    05:06 Somebody's pulse pressure, if it's 80, that difference between 130 and 50, has a very significant prognostic sign suggestive of aortic regurgitation.

    05:16 And it's something which you just wouldn't normally see for otherwise healthy people.

    05:21 Instead, I want you to focus on the pulse pressure.

    05:24 The characteristic finding of an early diastolic decrescendo murmur.

    05:29 And then one last important feature, you can imagine that if all that blood is going out, and going back in again, your left ventricle is having to do twice the work, right? And only is it trying to pump the blood that came from the left atrium there, it's not going to pump the blood that fell back in from the aortic arch into there.

    05:45 So, that blood is working overtime, and you're going to hear an S3.

    05:50 That third heart sound we talked about at the beginning of the lecture, because it's almost as if the heart is in failure.

    05:56 It's so overloaded.

    05:57 There's such increased diastolic filling pressures, that you're going to hear an S3.

    06:02 The presence of a third heart sound does serve as a high likely to the ratio for the presence of aortic insufficiency, and the setting of these other features.

    06:11 Alright, so that's aortic regurgitation.

    06:14 one last diastolic murmur, and this is the murmur of mitral stenosis.

    06:18 Now, fortunately, we don't see a lot of mitral stenosis anymore, ever since the advent of antibiotics that are being distributed all over the world, and to prevent rheumatic fever.

    06:28 Because basically, mitral stenosis is almost every time unless it's surgical or a few other rare birds.

    06:35 It's caused by progressive closure and stenosis of the mitral valve in the setting of rheumatic heart disease.

    06:42 The murmur of mitral stenosis, which I myself have only heard a handful of times is low.

    06:48 It is again diastolic.

    06:51 We are going to hear it over here at the apex of again, location, apex intensity.

    06:56 It's fairly quiet, though depending upon how loud it is that that does correlate with disease.

    07:01 And then the shape and the pitch.

    07:04 This sound is described as a rumble or even the growling of a dog.

    07:08 So it sounds like this.

    07:14 Very low in pitch, guttural, but fairly hollow systolic.

    07:19 So that's the murmur of mitral stenosis.

    07:21 And with that, I think we've covered all the different murmurs that we're going to potentially hear.

    07:27 And now we should move on to start talking about a few specific cardiac conditions that are non-valvular in nature.

    About the Lecture

    The lecture Diastolic Murmurs – Advanced Assessment by Stephen Holt, MD, MS is from the course Assessment of the Cardiovascular System (Nursing).

    Included Quiz Questions

    1. Between S1 and S2
    2. During S1
    3. Between S4 and S1
    4. During S4
    1. It is best heard between the tricuspid and pulmonic areas.
    2. It occurs when blood regurgitates back into the left ventricle.
    3. It is a holosystolic murmur.
    4. It is usually a high-intensity murmur.
    1. Systolic blood pressure - diastolic blood pressure
    2. Systolic blood pressure + diastolic blood pressure
    3. (Systolic blood pressure - diastolic blood pressure) divided by 60
    4. (Systolic blood pressure + diastolic blood pressure) x 2
    1. An audible S3 heart sound
    2. A low-pitched crescendo murmur over the mitral valve
    3. A bruit in the right carotid artery
    4. A low pulse pressure
    1. It is heard at the apex of the heart.
    2. The intensity correlates with how severe the stenosis is.
    3. It is the most common murmur.
    4. It is a high-pitched decrescendo murmur.

    Author of lecture Diastolic Murmurs – Advanced Assessment

     Stephen Holt, MD, MS

    Stephen Holt, MD, MS

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