In heart murmurs (synonyms: abnormal heart murmur a.n.k. ; Accidental heart murmur; Accidental systolic murmur; Benign accidental heart murmur; Functional heart murmur; Heart murmur; Cardiac murmur; Cardiac friction murmur; Nonorganic heart murmur; Precordial friction murmur; Splitting heart sounds; Systolic murmur; Widened heart murmur; Decreased heart murmur; ICD-10-GM R01.-: Heart murmurs and other cardiac sound phenomena) are all sound phenomena that are not heart sounds. Heart murmurs can be heard externally by means of a stethoscope (auscultation = listening) on the thorax (chest).
A distinction is made between heart sounds and murmurs. Heart sounds are physiological (normal) sound phenomena caused by the movements of the heart, whereas heart murmurs can indicate a clinical picture.
Heart murmurs can be caused by defects in the heart valves (valvular defects) or stenosis (narrowing) of the blood vessels (flow murmurs).
The following classifications are described in detail in the chapter “Classification”.
The following heart murmurs can be distinguished according to their temporal occurrence within the cardiac cycle (depending on systole or diastole):
- Systolic heart murmurs
- Diastolic heart murmurs
- Continuous heart murmurs
Furthermore, heart murmurs are divided into:
- Accidental heart murmurs
- Functional heart murmurs
- Organic heart murmurs
Other distinguishing characteristics include duration of the heart murmur, frequency, sound character/pattern, punctum maximum (site of greatest loudness), and conduction of the murmur.
In addition, extracardiac murmurs (“outside the heart”) may occur. This is pericardial rubbing, which occurs when inflammatory changes in the surfaces of the epicardium (“outer layer of the heart wall”) and pericardium (heart sac) rub against each other, e.g., in the context of dry pericarditis (inflammation of the heart sac).
In 33% of infants, an abnormal heart murmur occurs in the first 24 hours; within a week, this is even the case in up to 70%. However, within the first six months of life, any abnormal murmur should have disappeared.
During growth, heart murmurs, without cardiac pathology, occur in up to 50% of heart-healthy children and adolescents.
Heart murmurs can be a symptom of many diseases (see under “Differential Diagnoses”).
Course and prognosis: Cardiac murmur findings alone do not indicate significance. Heart murmurs can also be harmless in nature. In most cases, the cause of the murmur can only be determined by echocardiography (examination of the heart by ultrasound).
In newborns, a heart murmur is often due to a congenital (congenital) heart defect and must be evaluated immediately.
In a child with a heart murmur, a detailed history should first be taken to assess the risk factors for a possible underlying condition. Subsequently, further diagnostic testing by a specialist (pediatric cardiologist) should be considered. This also serves to reassure the usually unsettled parents. Only about 1% of those affected actually have a cardiac problem.
Prognosis ultimately depends on the nature of the cardiac problem or its severity.