Common abnormalities

Systolic murmurs. The causes of systolic murmurs are listed in Table 3.27.

Ejection systolic murmurs can be caused by an increased stroke volume (How murmur), or a stenosed aortic or pulmonary valve. Causes of flow murmurs include pregnancy, fever, bradycardia and atrial septal defect.

The murmur of aortic stenosis is usually audible all over the preeordium. including the apex (Fig. 3,31). ft may be harsh, or high pitched and musical, and radiates to the upper right sternal edge and carotids. The murmur is often loud and may be associated with a thrill. However, in critical aortic stenosis the degree of obstruction and the resultant deterioration in left ventricular function may reduce the cardiac output to such an extent that the intensity of the murmur is diminished.

Pansystolic murmurs are most frequently caused by mitral or tricuspid regurgitation, The murmur of mitral regurgitation radiates to the axilla, It is often loud and blowing in character, best heard at the apex (Fig. 3.30). In some patients the mitral valve prolapses during ventricular systole producing a mid- or late systolic murmur (Fig. 3.30).

Tricuspid incompetence is heard at the left sternal edge and associated with confirmatory signs including a large V

wave in the jugular venous pulse and a pulsatile liver.

Another cause of a pansystolic murmur is a ventricular septal defect. Even small congenital defects can cause a loud murmur at the left sternal edge, often associated with a thrill. A pansystolic murmur developing in a patient recovering from acute myocardial infarction is most commonly caused by rupture of the ventricular septum. Other possibilities include mitral incompetence caused by mpture of the chordae tendineae. or functional incompetence produced by acute left ventricular dilatation.

Diastolic murmurs. Early diastolic murmurs are typified by aortic regurgitation (Fig. 3.32). They are usually best heard at the left sternal edge, but are occasionally louder at the lower right sternal edge, Quiet early diastolic murmurs may be audible only in expiration with the patient leaning forward. Since the regurgitant blood volume must be ejected during the subsequent systole, aortic regurgitation leads to an increased stroke volume and may be associated with an ejection systolic flow murmur.

Pulmonary regurgitation is uncommon. It may be secondary to pulmonary artery dilatation in pulmonary hypertension (Graham Steell murmur).

The mid-diastolic murmur of mitral stenosis is a low-pitched rumbling sound which begins after the opening snap, if this is present (Fig. 3.33). It is best heard with the bell of the stethoscope at the apex. The whole cadence sounds like 'lup-ta-ta-roo' where lup is the loud first heart sound, ta-ta the second sound and opening snap and roo the mid-diastolic murmur. If the patient is in sinus rhythm, atrial contraction increases the blood flow across the stenosed valve leading to presystolic accentuation of the murmur.

100 Uncoiled aorta

Aortic Diastolic Murmur

Fig. 3.32 Features of aortic regurgitation. The pulse pressure is usually Increased; the jet from the aortic valve (AV) impinges on the interventricular septum (arrow) during diastole, producing a high-pitched murmur which is best heard with the diaphragm. The diagrammatic representation of the phonocardiogram also shows the systolic murmur which is common because of the increased flow through the aortic valve In systole.

Lean patient forward with breath held in expiration to hear murmur best

Increased pulse pressure mmHg 150

Fig. 3.32 Features of aortic regurgitation. The pulse pressure is usually Increased; the jet from the aortic valve (AV) impinges on the interventricular septum (arrow) during diastole, producing a high-pitched murmur which is best heard with the diaphragm. The diagrammatic representation of the phonocardiogram also shows the systolic murmur which is common because of the increased flow through the aortic valve In systole.

Increased pulse pressure

100 Uncoiled aorta

Lean patient forward with breath held in expiration to hear murmur best

Left atrium Mitral valve

Stenosis Mitral Valve

Left atrial appendix

Roll patient towards left to hear murmur best

Fig. 3.33 Features of mitral stenosis. There is a pressure gradient across the mitral valve; in this example it continues throughout diastole. This causes a sharp movement of the lethered anterior cusp of the mitral valve at the lime when the flow commences, and the opening snap (OS) results. The jet through the stenotic valve (arrow) strikes the endocardium at the cardiac apex. The murmur which results is best heard with the bell lightly applied over Ihe apex.

Gradient across valve

Left atrium Mitral valve

Roll patient towards left to hear murmur best

Left atrial appendix

Gradient across valve mmHg 125

Loud Si

Fig. 3.33 Features of mitral stenosis. There is a pressure gradient across the mitral valve; in this example it continues throughout diastole. This causes a sharp movement of the lethered anterior cusp of the mitral valve at the lime when the flow commences, and the opening snap (OS) results. The jet through the stenotic valve (arrow) strikes the endocardium at the cardiac apex. The murmur which results is best heard with the bell lightly applied over Ihe apex.

Best heard 2nd right

Dorsalis Pedis

Left ventricular enlargement

Large volume peripheral pulses (including dorsalis pedis pulse in infants)

Fig. 3.34 Features of a persistent patent arterial duct.

Best heard 2nd right

S1 Continuous Sa murmur Left to right shunt from aorta to pulmonary artery

Pulmonary artery shadow may be enlarged

Left ventricular enlargement

Large volume peripheral pulses (including dorsalis pedis pulse in infants)

Fig. 3.34 Features of a persistent patent arterial duct.

The murmur of tricuspid stenosis is similar to mitral stenosis, but it is rare. An Austin Flint murmur is a middiastolic murmur caused by a jet of blood in aortic regurgitation impinging directly on the anterior leaflet of the mitral valve thereby causing it to close and restricting the inflow to the left ventricle.

Continuous murmurs are rare in adults. The commonest cause is a patent arterial duct which connects the upper descending aorta and pulmonary artery, and normally closes just after birth. The murmur is best heard at the upper left sternal edge, radiating to the left scapula. Its continuous character has been described as machinery-like (Fig. 3.34).

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Blood Pressure Health

Your heart pumps blood throughout your body using a network of tubing called arteries and capillaries which return the blood back to your heart via your veins. Blood pressure is the force of the blood pushing against the walls of your arteries as your heart beats.Learn more...

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  • orgulas
    Where to hear diastolic murmur?
    8 years ago

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