S3 vs S4 heart sounds, especially in restrictive cardiomyopathy - USMLE Forums
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Old 04-23-2011
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Stethoscope S3 vs S4 heart sounds, especially in restrictive cardiomyopathy

As I understand it, S3 is caused by the sudden deceleration of blood hitting the wall of the left ventricle in the early filling phase, while S4 is caused by strong atrial contraction in the late filling phase in response to a noncompliant ventricle.

What I don't understand is, why doesn't a noncompliant ventricle produce an S3 as well? I would imagine there would be a much more significant deceleration of blood hitting the left ventricular wall in the case of restrictive cardiomyopathy or concentric hypertrophy, even without volume overload.

Thanks,
Tig
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Old 04-23-2011
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Hi, Tiq2575,

Non compliant ventricle does product S3, non complaint ventricle also products S4. S3 and S4 happens in different phases of cardiac contraction, but can be all caused by non compliant ventricle
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Old 04-23-2011
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Thanks usluipek! In that case, could we theoretically assume that a concentrically hypertrophied heart is producing a sub-audible S3 as well, because of its reduced compliance?

Best,
Tig
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Old 04-23-2011
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Reference: http://emedicine.medscape.com/articl...clinical#a0217
Quote:
A loud early diastolic filling sound (S3) may be present but is uncommon in amyloidosis. A fourth heart sound is almost never present, possibly secondary to amyloid infiltration of the atria.
Amyloidosis is the most common cause of restrictive cardiomyopathy.

Also see my post here;
Third and Fourth Heart Sounds
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Old 04-23-2011
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Yes, Tiq2575, concentrically hypertrophied heart can produce S3 if hypertrophy leads to reduced compliance. But the most common pathological causes of S3 are dilated cardiomyopathy and heart failure.
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Cardiovascular-, Clinical-Signs, Pathology-, Physiology-

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