Cardiovascular examination - Part Four - Auscultation of the heart
Auscultation of the heart is undertaken to establish whether the heart sounds are normal and if there are any addit…
VOL: 103, ISSUE: 28, PAGE NO: 26
Author Phil Jevon, PGCE, BSc, RN, is resuscitation officer/clinical skills lead and honorary clinical lecturer, University of Birmingham Medical School
Alan Cunnington, FRCP, MD, is consultant physician; both at Manor Hospital, Walsall
Auscultation of the heart is undertaken to establish whether the heart sounds are normal and if there are any additional sounds (Scott and MacInnes, 2006). It is a skill that requires detailed knowledge, practice and experience to ensure competency at distinguishing what is normal from what is abnormal.
The priority for practitioners is to first master the recognition of normal heart sounds. Once this is achieved it will be possible to identify heart sounds that are abnormal (Cox and Roper, 2005).
In the first part of this four-part series on cardiovascular examination normal heart sounds, related physiology and the use of the stethoscope were discussed. In this final part, an introduction to abnormal heart sounds will be provided.
For readers who require more detailed information, Cox and Roper (2005) provide a comprehensive account of the recognition of abnormal heart sounds.
ABNORMAL HEART SOUNDS
During auscultation of the heart it is important to detect the presence of added sounds and murmurs (Longmore et al, 2007) including:
- Third heart sound (S3) - a low-pitched sound heard just after the second heart sound (S2). The most important pathological cause is left ventricular failure, although this can be a normal finding in both healthy young persons and pregnant women (Cox and Roper, 2005);
- Fourth heart sound (S4) - a low-pitched sound heard just before the first heart sound (S1). This is never normal; it indicates a non-compliant ventricle (Cox and Roper, 2005);
- Cardiac murmur - characterised by a whooshing or blowing noise. Causes include turbulent blood flow across an abnormal valve, a septal defect and an outflow obstruction. Sometimes it is a normal finding (Douglas et al, 2005). If the murmur is present between the two heart sounds (that is, between S1 and S2), it is termed a systolic murmur. If present between each set of two heart sounds (that is, between S2 and S1), it is termed a diastolic murmur (Scott and MacInnes, 2006). Systolic murmurs are more common and easier to hear than diastolic murmurs (Cox and Roper, 2005).
There are two types of diastolic murmurs:
- Early diastolic murmurs - a high-pitched sound beginning loudly then getting quieter rapidly. It is most commonly caused by aortic regurgitation. At the beginning of diastole the pressure in the aorta is at its maximum before then falling - hence in aortic valve disease regurgitation of blood back across the aortic valve can occur, particularly at the beginning of diastole when the pressure in the aorta is high.
- Mid-diastolic murmurs - a low-pitched sound, most commonly caused by mitral stenosis - turbulent flow of blood from the left atrium into the left ventricle across the diseased mitral valve (Cox and Roper, 2005).
There are three types of systolic murmurs:
- Pansystolic murmurs - usually a gentle blowing sound heard during systole; most common cause is mitral valve disease - incomplete closure of the mitral valve leads to regurgitation of blood back across the valve during ventricular contraction.
- Ejection systolic murmurs - usually a harsh sound, the most common cause is aortic stenosis - during left ventricular contraction, bloodflow across the diseased aortic valve is turbulent.
- Late systolic murmurs - usually seen late in systole, often caused by mitral valve prolapse which, if severe, can cause some regurgitation (Cox and Roper, 2005).
- Pericardial friction rub - this is described as a creaking sound similar to that of someone walking on firm snow. Due to pericarditis (inflammation of the pericardium), this is best heard while the patient is holding their breath (Ford et al, 2005).
This should be undertaken as follows:
- Explain the procedure and obtain consent;
- Auscultate over the tricuspid area using the stethoscope bell (Fig 1). This is the optimum position for detecting the mid-diastolic murmur of tricuspid stenosis;
- Auscultate over the tricuspid area using the diaphragm (Fig 2). This is the optimum position to detect the pansystolic (heard throughout systole) murmur associated with tricuspid regurgitation and pericardial friction rub;
- Auscultate over the pulmonary area using the diaphragm (Fig 3). This is the optimum position to detect pulmonary murmurs.
- Auscultate over the aortic area using the diaphragm (Fig 4). This is the optimum position to detect murmurs associated with aortic stenosis.
- Listen for additional heart sounds and murmurs between S1 and S2.
- While asking the patient to hold their breath, auscultate over each carotid artery. This is to detect carotid bruits and aortic systolic murmurs radiating to the carotid arteries (Fig 5) (Ford et al, 2005).
- Ask the patient to sit forward and to hold their breath in mid expiration and auscultate with the diaphragm along the left sternal edge. This is to detect a diastolic murmur associated with aortic incompetence (Fig 6) (Ford et al, 2005).
- Document the clinical findings in the patient’s notes.
This procedure should be undertaken only after approved training, supervised practice and competency assessment, and carried out in accordance with local policies and protocols.
- This article has been double-blind peer-reviewed.