Murmurs - Heart Sounds of Great Clinical Importance For Diagnosis
A very important category of heart sounds is murmurs, which are produced by vibrations within the heart chambers or in the major arteries from the back and forth flow of blood.
Murmurs are abnormal sounds produced by turbulent blood flow within the heart chambers or vessels.
The most common cause of murmurs is an abnormal shunting of blood between two heart chambers or between vessels.
However, murmurs can also be produced by disturbing the flow of fluid through a vessel as result of • Increasing the rate of flow • Constricting or dilating the lumen, and • Creating some type of irregularity on the vessel wall which vibrates as fluid flows past, such as an aneurysm.
Murmurs are classified according to their timing within the cardiac cycle.
• Between S1 and S2 is Systolic murmurs • Between S2 and S1 is diastolic murmur Systolic ejection begins after the first heart sound, attain a peak during mid-systole, and terminate before the second heart sound.
Pansystolic or holosystolic is during all of systole Pandiastolic or holodiastolic is during all of diastole Prodiastolic is Early diastole Presystolic is late diastole Continuous is the continuation of all of systole and all or part of diastole.
Murmurs are classified as; 1.
Innocent, occurring in individuals with no anatomic or physiologic abnormality 2.
Functional, occurring in individuals with no anatomic cardiac defect but with a physiologic abnormality such as anemia.
3.
Organic, occurring in individuals with a cardiac defect with or without a physiologic abnormality.
The description and classification of murmurs are skills that require considerable practices and training.
In general the doctor should be able to recognize murmurs as distinct swishing sounds that occur in addition to the normal heart sounds.
The following information should be found: 1.
Location of the area of the heart where the murmur is heard best.
2.
Time of the occurrence of the murmur within the S1 S2 cycle.
3.
Evaluation of its intensity in relationship to the child's position.
4.
Estimation of its loudness.
The following guidelines can be used in distinguishing between innocent and organic murmurs.
Innocent murmurs generally are: 1.
systolic, that is, they occur with or after S1 2.
Of short duration and have no transmission to other areas of the heart.
3.
Grade III or less in intensity and do not increase over time.
4.
Usually loudest in the pulmonic area (sound or third intercostals space along the left sternal border) 5.
Variable in relationship to positions, respiration, and activity (for example, audible in the supine position but absent in the sitting position; may be louder with exercise, fever, anxiety in the sitting position; may be louder with exercise, fever, anxiety, or anemia).
6.
Not associated with any physical signs of cardiac disease.
7.
Usually of a low-pitched, musical, or groaning quality.
Murmurs caused by congenital defects involving the septum or great vessels are usually heard best near the sternal borders or over the base of the heart.
Those of valvular origin are typically loudest over the respective auscultating valvular area, in the direction of blood flow.
Murmurs that originate on the right side of the heart are subject to change during respiration as a result of intra-thoracic pressure that prolongs right ventricular filling.
Therefore murmurs originating on the right side of the heart increase during inspiration.
There are a number of other abnormal sounds, such as ejection clicks, snaps, gallops, and hums.
Murmurs are abnormal sounds produced by turbulent blood flow within the heart chambers or vessels.
The most common cause of murmurs is an abnormal shunting of blood between two heart chambers or between vessels.
However, murmurs can also be produced by disturbing the flow of fluid through a vessel as result of • Increasing the rate of flow • Constricting or dilating the lumen, and • Creating some type of irregularity on the vessel wall which vibrates as fluid flows past, such as an aneurysm.
Murmurs are classified according to their timing within the cardiac cycle.
• Between S1 and S2 is Systolic murmurs • Between S2 and S1 is diastolic murmur Systolic ejection begins after the first heart sound, attain a peak during mid-systole, and terminate before the second heart sound.
Pansystolic or holosystolic is during all of systole Pandiastolic or holodiastolic is during all of diastole Prodiastolic is Early diastole Presystolic is late diastole Continuous is the continuation of all of systole and all or part of diastole.
Murmurs are classified as; 1.
Innocent, occurring in individuals with no anatomic or physiologic abnormality 2.
Functional, occurring in individuals with no anatomic cardiac defect but with a physiologic abnormality such as anemia.
3.
Organic, occurring in individuals with a cardiac defect with or without a physiologic abnormality.
The description and classification of murmurs are skills that require considerable practices and training.
In general the doctor should be able to recognize murmurs as distinct swishing sounds that occur in addition to the normal heart sounds.
The following information should be found: 1.
Location of the area of the heart where the murmur is heard best.
2.
Time of the occurrence of the murmur within the S1 S2 cycle.
3.
Evaluation of its intensity in relationship to the child's position.
4.
Estimation of its loudness.
The following guidelines can be used in distinguishing between innocent and organic murmurs.
Innocent murmurs generally are: 1.
systolic, that is, they occur with or after S1 2.
Of short duration and have no transmission to other areas of the heart.
3.
Grade III or less in intensity and do not increase over time.
4.
Usually loudest in the pulmonic area (sound or third intercostals space along the left sternal border) 5.
Variable in relationship to positions, respiration, and activity (for example, audible in the supine position but absent in the sitting position; may be louder with exercise, fever, anxiety in the sitting position; may be louder with exercise, fever, anxiety, or anemia).
6.
Not associated with any physical signs of cardiac disease.
7.
Usually of a low-pitched, musical, or groaning quality.
Murmurs caused by congenital defects involving the septum or great vessels are usually heard best near the sternal borders or over the base of the heart.
Those of valvular origin are typically loudest over the respective auscultating valvular area, in the direction of blood flow.
Murmurs that originate on the right side of the heart are subject to change during respiration as a result of intra-thoracic pressure that prolongs right ventricular filling.
Therefore murmurs originating on the right side of the heart increase during inspiration.
There are a number of other abnormal sounds, such as ejection clicks, snaps, gallops, and hums.
