Heart sound: Difference between revisions
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==Normal heart sounds== | ==Normal heart sounds== | ||
{{Image|Gray-image1218.gif|right|350px|The location of the heart below the thoracic wall.}} | |||
A diagram of the [http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm&partid=333&rendertype=figure&id=A684 cardiac cycle is available] and helps understand the normal heart sounds.<ref name="isbn0-409-90077-X">{{cite book |author=Felner JM |authorlink= |editor=Walker HK, Hall WD, Hurst JW |others= |title=Clinical methods: the history, physical, and laboratory examinations |edition=3rd |language=English |publisher=Butterworths |location=London |year=1990 |origyear= |pages= |chapter=The First Heart Sound|quote=See image of cardiac cycle at http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm&partid=333&rendertype=figure&id=A684 |isbn=0-409-90077-X |oclc= |doi= |url=http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm|chapterurl=http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm&part=A678 |accessdate=|id={{LCC|RC71 .C63}} }} [http://lccn.loc.gov/87013782 Library of Congress]</ref> | A diagram of the [http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm&partid=333&rendertype=figure&id=A684 cardiac cycle is available] and helps understand the normal heart sounds.<ref name="isbn0-409-90077-X">{{cite book |author=Felner JM |authorlink= |editor=Walker HK, Hall WD, Hurst JW |others= |title=Clinical methods: the history, physical, and laboratory examinations |edition=3rd |language=English |publisher=Butterworths |location=London |year=1990 |origyear= |pages= |chapter=The First Heart Sound|quote=See image of cardiac cycle at http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm&partid=333&rendertype=figure&id=A684 |isbn=0-409-90077-X |oclc= |doi= |url=http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm|chapterurl=http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm&part=A678 |accessdate=|id={{LCC|RC71 .C63}} }} [http://lccn.loc.gov/87013782 Library of Congress]</ref> | ||
Revision as of 07:12, 8 June 2009
In medicine, heart sounds are the "sounds heard over the cardiac region produced by the functioning of the heart. There are four distinct sounds: the first occurs at the beginning of systole and is heard as a "lubb" sound; the second is produced by the closing of the aortic valve and pulmonary valve and is heard as a "dupp" sound; the third is produced by vibrations of the ventricular walls when suddenly distended by the rush of blood from the heart atria; and the fourth is produced by atrial contraction and ventricular filling."[1]
Normal heart sounds
A diagram of the cardiac cycle is available and helps understand the normal heart sounds.[2]
S1
S1, which originates from closure of the mitral and tricuspid valves is normally louder than S2 at the cardiac apex (fifth left intercostal space).[3]
S2
S2 is normally louder than S1 at the cardiac base (second left intercostal space).[4] "With quiet respiration, A2 will normally precede P2 by 0.02 to 0.08 second (mean, 0.03 to 0.04 sec) with inspiration."[5] Intervals less than 30 to 40 msec will sound like a single sound.[5]
The S2 is composed of A2 and P2:
- A2 originates from closure of the aortic valve
- P2 originates from closure of the pulmonic valve, is best heard at the cardiac base (second left intercostal space), and is quieter than A2.
Abnormal heart sounds
S2
More discussion is available online.[5]
- Fixed split S2 may be from interatrial communication such as atrial septal defect
- Hemodynamic abnormalities: interatrial communication such as an atrial septal defect
- Paradoxical split S2 may be from
- Conduction abnormalities: left bundle branch block, artificial RV pacing, preexcitation of the RV
- Hemodynamic abnormalities: aortic valve stenosis
- Wide split S2 may be from
- Conduction abnormalities: right bundle branch block, artificial LV pacing, and preexcitation of the LV
- Hemodynamic abnormalities: pulmonary stenosis and pulmonary hypertension
References
- ↑ Anonymous (2024), Heart sound (English). Medical Subject Headings. U.S. National Library of Medicine.
- ↑ Felner JM (1990). “The First Heart Sound”, Walker HK, Hall WD, Hurst JW: Clinical methods: the history, physical, and laboratory examinations (in English), 3rd. London: Butterworths. LCC RC71 .C63. ISBN 0-409-90077-X. “See image of cardiac cycle at http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=cm&partid=333&rendertype=figure&id=A684” Library of Congress
- ↑ McGee, Steven R. (2007). “The First and Second Heart Sounds”, Evidence-Based Physical Diagnosis, 2nd. Philadelphia: Saunders, 418. ISBN 1-4160-2898-6.
- ↑ McGee, Steven R. (2007). “Auscultation of the Heart: General Principles”, Evidence-Based Physical Diagnosis, 2nd. Philadelphia: Saunders, 415. ISBN 1-4160-2898-6.
- ↑ 5.0 5.1 5.2 Felner JM (1990). “The Second Heart Sound”, Walker HK, Hall WD, Hurst JW: Clinical methods: the history, physical, and laboratory examinations (in English), 3rd. London: Butterworths. LCC RC71 .C63. ISBN 0-409-90077-X. Library of Congress
- ↑ McGee, Steven R. (2007). “The First and Second Heart Sounds”, Evidence-Based Physical Diagnosis, 2nd. Philadelphia: Saunders, 422. ISBN 1-4160-2898-6.
- ↑ 7.0 7.1 Harris A, Sutton G (November 1968). "Second heart sound in normal subjects". British heart journal 30 (6): 739–42. PMID 5718983. PMC 487796. [e] PubMed Central
Bibliography
- Drummond Rennie; David Simel (2008). THE RATIONAL CLINICAL EXAMINATION: EVIDENCE-BASED CLINICAL DIAGNOSIS (Jama & Archives Journals). McGraw-Hill Professional. ISBN 0-07-159030-7.
- McGee, Steven R. (2007). Evidence-Based Physical Diagnosis. Philadelphia: Saunders. ISBN 1-4160-2898-6.
- (1990) Walker HK, Hall WD, Hurst JW: Clinical methods: the history, physical, and laboratory examinations (in English), 3rd. London: Butterworths. LCC RC71 .C63. ISBN 0-409-90077-X. Library of Congress