Heart murmur classification: Difference between revisions
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==Overview== | ==Overview== | ||
A heart murmur can be classified based on the various characteristics of the murmur. Quality, pitch, intensity, timing, shape, and location can be used to classify the heart murmur into different categories. From a clinical perspective, a heart murmur can be classified into two important categories: pathologic murmurs, which require further evaluation, and innocent murmurs, which occur due to physiologic changes. | |||
==Classification== | |||
==Quality of the Murmur== | ===Quality of the Murmur=== | ||
The quality of a murmur can be characterized as | The quality of a murmur can be characterized as: | ||
*Blowing: [[Mitral regurgitation]] often has this quality | *Blowing: [[Mitral regurgitation]] often has this quality | ||
*Harsh: [[Aortic stenosis]] may have this quality | *Harsh: [[Aortic stenosis]] may have this quality | ||
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*Musical | *Musical | ||
==Pitch of the Murmur== | ===Pitch of the Murmur=== | ||
The pitch of a murmur is either low, medium or high. Low pitched murmurs are best heard with the bell of the stethoscope while high pitched sounds are best heard with the diaphragm of the [[stethoscope]]. | The pitch of a murmur is either low, medium, or high. Low pitched murmurs are best heard with the bell of the stethoscope while high pitched sounds are best heard with the diaphragm of the [[stethoscope]]. | ||
==Intensity of Murmur== | ===Intensity of Murmur=== | ||
Intensity refers to the loudness of the murmur, and it is graded on a scale from 0-6/6, with 6 being the loudest. <ref> Freeman AR, Levine SA. Clinical significance of systolic murmurs: study of 1000 consecutive "noncardiac" cases. Ann Intern Med. 1933, 6: 1371–85. </ref> | Intensity refers to the loudness of the murmur, and it is graded on a scale from 0-6/6, with 6 being the loudest. <ref> Freeman AR, Levine SA. Clinical significance of systolic murmurs: study of 1000 consecutive "noncardiac" cases. Ann Intern Med. 1933, 6: 1371–85. </ref> | ||
{| class="wikitable" | {| class="wikitable" | ||
|- | |- | ||
| ''' | | '''Grading of Murmurs''' | ||
| '''Description''' | | '''Description''' | ||
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Systolic [[thrills]] (palpable murmurs best felt by the tips of the fingers which feel similar to a cat purring) are associated with murmurs of grade 4 or louder. Systolic murmurs of grade 3 or more in intensity are usually hemodynamically significant. <ref>Norton P, O'Rourke RA. Cardiac murmurs (Goldman L, Braunwald E, eds. Cardiology for the Primary Physician). 2nd ed. Philadelphia PA Saunders, 2003: 151-68 </ref> | Systolic [[thrills]] (palpable murmurs best felt by the tips of the fingers which feel similar to a cat purring) are associated with murmurs of grade 4 or louder. Systolic murmurs of grade 3 or more in intensity are usually hemodynamically significant. <ref>Norton P, O'Rourke RA. Cardiac murmurs (Goldman L, Braunwald E, eds. Cardiology for the Primary Physician). 2nd ed. Philadelphia PA Saunders, 2003: 151-68 </ref> | ||
==Timing of the Murmur== | ===Timing of the Murmur=== | ||
The timing of heart murmurs can be broadly classified as either '''diastolic''' or '''systolic''' <ref> Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:104-105 ISBN 140510368X </ref>. Systole is considerably shorter than diastole at normal heart rates. At rapid heart rates, the examiner can usually time the murmur by simultaneous palpation of the lower right carotid artery or can rely on the fact that the [[Heart sounds|S<sub>2</sub>]] is usually the louder sound at the base. Once [[Heart sounds|S<sub>2</sub>]] is identified, murmurs can be located properly in the cardiac cycle as systolic or diastolic. The inching technique, popularized by Harvey and Levine, consists of slowly moving the stethoscope down from the base to the apex while repeatedly fixing the cardiac cycle in mind, using [[Heart sounds|S<sub>2</sub>]] as a reference point. In [[sinus tachycardia]], [[carotid sinus]] pressure can temporarily slow the rate and make it possible to differentiate systole from diastole. | The timing of heart murmurs can be broadly classified as either '''diastolic''' or '''systolic''' <ref> Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:104-105 ISBN 140510368X </ref>. Systole is considerably shorter than diastole at normal heart rates. At rapid heart rates, the examiner can usually time the murmur by simultaneous palpation of the lower right carotid artery or can rely on the fact that the [[Heart sounds|S<sub>2</sub>]] is usually the louder sound at the base. Once [[Heart sounds|S<sub>2</sub>]] is identified, murmurs can be located properly in the cardiac cycle as systolic or diastolic. The inching technique, popularized by Harvey and Levine, consists of slowly moving the stethoscope down from the base to the apex while repeatedly fixing the cardiac cycle in mind, using [[Heart sounds|S<sub>2</sub>]] as a reference point. In [[sinus tachycardia]], [[carotid sinus]] pressure can temporarily slow the rate and make it possible to differentiate systole from diastole. | ||
* '''Diastolic''' heart murmurs are not normal, while '''systolic''' heart murmurs may be normal or abnormal | * '''Diastolic''' heart murmurs are not normal, while '''systolic''' heart murmurs may be normal or abnormal | ||
* '''Diastolic''' murmurs ''always'' require further evaluation | * '''Diastolic''' murmurs ''always'' require further evaluation | ||
* '''Systolic''' murmurs are most often benign | * '''Systolic''' murmurs are most often benign and are due to rapid flow rates | ||
* '''Systolic''' murmurs are not normal when accompanied by a [[heave]] | * '''Systolic''' murmurs are not normal when accompanied by a [[heave]] | ||
==Shape== | ===Shape=== | ||
Shape refers to the intensity over time; murmurs can be crescendo (increasing), decrescendo (diminishing), crescendo-decrescendo (increasing-decreasing or diamond shaped) and plateau (unchanged in intensity). | Shape refers to the intensity over time; murmurs can be crescendo (increasing), decrescendo (diminishing), crescendo-decrescendo (increasing-decreasing or diamond-shaped), and plateau (unchanged in intensity). | ||
==Location== | ===Location=== | ||
Location refers to where the heart murmur is | Location refers to where the heart murmur is best heard. There are 6 places on the anterior chest to listen for heart murmurs. Each of these locations roughly correspond to a specific part of the heart. The first five out of six are adjacent to the sternum. These locations are: | ||
*2<sup>nd</sup> right intercostal space | *2<sup>nd</sup> right intercostal space | ||
*2<sup>nd</sup> left intercostal space | *2<sup>nd</sup> left intercostal space | ||
| Line 64: | Line 64: | ||
*5<sup>th</sup> mid-clavicular intercostal space | *5<sup>th</sup> mid-clavicular intercostal space | ||
==References== | ==References== | ||
{{Reflist|2}} | {{Reflist|2}} | ||
{{WH}} | |||
{{WS}} | |||
[[Category:Emergency medicine]] | [[Category:Emergency medicine]] | ||
[[Category:Cardiology]] | [[Category:Cardiology]] | ||
[[Category:Physical examination]] | [[Category:Physical examination]] | ||
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Latest revision as of 22:54, 20 January 2021
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
A heart murmur can be classified based on the various characteristics of the murmur. Quality, pitch, intensity, timing, shape, and location can be used to classify the heart murmur into different categories. From a clinical perspective, a heart murmur can be classified into two important categories: pathologic murmurs, which require further evaluation, and innocent murmurs, which occur due to physiologic changes.
Classification
Quality of the Murmur
The quality of a murmur can be characterized as:
- Blowing: Mitral regurgitation often has this quality
- Harsh: Aortic stenosis may have this quality
- Rumbling: Mitral stenosis may have this quality
- Musical
Pitch of the Murmur
The pitch of a murmur is either low, medium, or high. Low pitched murmurs are best heard with the bell of the stethoscope while high pitched sounds are best heard with the diaphragm of the stethoscope.
Intensity of Murmur
Intensity refers to the loudness of the murmur, and it is graded on a scale from 0-6/6, with 6 being the loudest. [1]
| Grading of Murmurs | Description |
| Grade 1 | Very faint, heard only after listener has "tuned in"; may not be heard in all positions. |
| Grade 2 | Quiet, but heard immediately after placing the stethoscope on the chest. |
| Grade 3 | Moderately loud. |
| Grade 4 | Murmur is very loud, with palpable thrill. |
| Grade 5 | Murmur is extremely loud, with palpable thrill, and can be heard if only the edge of the stethoscope is in contact with the skin, but cannot be heard if the stethoscope is removed from the skin. |
| Grade 6 | Murmur is exceptionally loud, with palpable thrill, and can be heard with the stethoscope just removed from contact with the chest. |
Systolic thrills (palpable murmurs best felt by the tips of the fingers which feel similar to a cat purring) are associated with murmurs of grade 4 or louder. Systolic murmurs of grade 3 or more in intensity are usually hemodynamically significant. [2]
Timing of the Murmur
The timing of heart murmurs can be broadly classified as either diastolic or systolic [3]. Systole is considerably shorter than diastole at normal heart rates. At rapid heart rates, the examiner can usually time the murmur by simultaneous palpation of the lower right carotid artery or can rely on the fact that the S2 is usually the louder sound at the base. Once S2 is identified, murmurs can be located properly in the cardiac cycle as systolic or diastolic. The inching technique, popularized by Harvey and Levine, consists of slowly moving the stethoscope down from the base to the apex while repeatedly fixing the cardiac cycle in mind, using S2 as a reference point. In sinus tachycardia, carotid sinus pressure can temporarily slow the rate and make it possible to differentiate systole from diastole.
- Diastolic heart murmurs are not normal, while systolic heart murmurs may be normal or abnormal
- Diastolic murmurs always require further evaluation
- Systolic murmurs are most often benign and are due to rapid flow rates
- Systolic murmurs are not normal when accompanied by a heave
Shape
Shape refers to the intensity over time; murmurs can be crescendo (increasing), decrescendo (diminishing), crescendo-decrescendo (increasing-decreasing or diamond-shaped), and plateau (unchanged in intensity).
Location
Location refers to where the heart murmur is best heard. There are 6 places on the anterior chest to listen for heart murmurs. Each of these locations roughly correspond to a specific part of the heart. The first five out of six are adjacent to the sternum. These locations are:
- 2nd right intercostal space
- 2nd left intercostal space
- 3rd left intercostal space
- 4th left intercostal space
- 5th left intercostal space
- 5th mid-clavicular intercostal space
References
- ↑ Freeman AR, Levine SA. Clinical significance of systolic murmurs: study of 1000 consecutive "noncardiac" cases. Ann Intern Med. 1933, 6: 1371–85.
- ↑ Norton P, O'Rourke RA. Cardiac murmurs (Goldman L, Braunwald E, eds. Cardiology for the Primary Physician). 2nd ed. Philadelphia PA Saunders, 2003: 151-68
- ↑ Kahan, Scott, Smith, Ellen G. In A Page: Signs and Symptoms. Malden, Massachusetts: Blackwell Publishing, 2004:104-105 ISBN 140510368X