Freshman Medical Education
Physical Diagnosis
HEART SOUNDS
A
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Heart Auscultation Instruction
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developed for
The Freshman Physical Diagnosis Course, Winter 1995
Instructor: Leonard Werner, M.D., Associate Dean of Educational Affairs
This Shocked animation was created in collaboration with Jeff Sale.
This animation is being displayed in a reduced scale. It was developed to fill a 640x480 display, but has been reduced to 480x350 to minimize the time required for downloading. Thus, the quality which you see here is noticeably poorer than that of the original set.
If you are interested in obtaining more information about the complete set of Heart Sounds, please send email to Jeff Sale, or link to Jeff Sale's Home Page for his contact information.
Diastolic Murmurs
A. Diastolic murmurs are classified according to their mechanism of production. Diastolic filling murmurs (rumbles) are produced by forward flow across the AV valves. Diastolic regurgitant murmurs are produced by retrograde flow across incompetent semilunar valves.
B. The prototype of the diastolic regurgitant murmur originating in the left heart is that associated with aortic regurgitation.
The murmur begins with A2, is decrescendo, and ends in late diastole. Mild forms of aortic regurgitation may produce murmurs that end in mid diastole. The murmur of aortic regurgitation is heard best at the 2nd right intercostal space, 3rd left intercostal space, and apex. It is accentuated by having the patient lean forward and hold his breath in forced exhalation. The murmur has a high pitched, blowing quality. The murmur is increased in intensity by increasing peripheral vascular resistance (handgrip, squatting, exercise). Other manifestations of aortic insufficiency include:
- Wide pulse pressure.
- Water-Hammer pulse with a bisferiens quality.
- Quincke's pulse - a pulsation of the blood in the proximal finger nail bed with pressure applied to the distal nail bed. This occurs normally in some people, but is more common and prominent in patients with aortic insufficiency.
- DeMusset's sign - head bobbing with each heart beat
- Duroziez's sign - a "to and fro" bruit over the femoral artery resulting from manual pressure applied over the femoral artery while listening with the diaphragm of the stethoscope.
- Dullness to percussion, increased tactile fremitus, and egophony at the lower tip of the left scapula secondary to lung consolidation from the enlarged heart. Mimics Ewart's sign of a large pericardial effusion.
- S2 is single and snapping.
- The apical impulse is displaced down and to the left, having a hyperdynamic quality.
- An S3 sound is common due to rapid ventricular filling.
- Two additional murmurs often accompany that of severe aortic regurgitation.
- a. An aortic ejection (midsystolic) murmur due to increased volume of blood being ejected across the aortic valve in the forward direction.
- b. A low pitched, mid to late diastolic rumbling murmur at the apex due to the regurgitant flow impinging upon the anterior leaflet of the mitral valve and partially closing it. This situation creates a "functional" mitral stenosis. This murmur is termed the Austin-Flint murmur.
Why is this so important?
Normally, students in a physical diagnosis course must piece together various sources of information, such as sounds from a cassette tape (linear media), pictures from a text, and brief experiences with a subject in an examination, in order to create in their minds what is integrated here in this shocked Macromedia Director® animation. The advantage to watching an animation is not only obvious, but the additional advantage of accessing it for free over the World Wide Web is both obvious and very exciting. This kind of instructional technology rapid prototyping for medical education at the undergraduate and graduate level is what we emphasize here at San Diego State University College of Sciences Instructional Technologies.
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