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JuhaniAiraksinen

The Most Common Types of Acquired Adult Valvular Heart Disease and Associated Murmurs

Essentials

  • Heart murmurs are usually generated by a turbulent and increased flow of blood.
  • The majority of soft systolic murmurs are innocent (benign).
  • The intensity (loudness) of a murmur does not always correlate with the severity of the valvular disease.
  • The intensity of a murmur induced by significant valvular disease usually decreases in severe heart failure, or the murmur may even disappear altogether.
  • A new murmur suggestive of valvular regurgitation in a febrile patient should always arouse the suspicion of endocarditis.
  • If the condition of a patient with an artificial heart valve suddenly deteriorates, complications relating to the valve prosthesis should always be borne in mind.
  • Endocarditis prophylaxis is no longer considered necessary in patients with acquired valvular disease.
  • This article does not address causes of murmurs that are rare in adults, including pulmonary valve stenosis, mitral valve stenosis, congenital heart diseases, ventricular septal rupture and pericardial rub.

The principal aims of clinical assessment

  • Is the murmur caused by a valvular disease or is it innocent?
  • Are the patient's symptoms (dyspnoea, reduced exercise capacity, chest pain) or ECG changes (LVH) caused by valvular disease?
  • When should a patient with a new murmur or valvular disease be referred to specialized care for echocardiography and assessment by a cardiologist?
  • When is emergency care or urgent assessment indicated?
  • On what should the follow-up focus and at what point is surgical management indicated?

Systolic murmurs

Aortic stenosis (AS)

  • Aortic stenosis is the most frequent adult valvular disease in the West (accounting for about 40% of all cases of valvular disease).
  • AS is common the elderly and must always be considered as a possible cause of heart failure in an elderly patient.
  • The murmur (Image 1/3)
    • Has a harsh quality, peaks in mid-to-late systole. An early systolic ejection murmur suggests a less stenotic valve, while a more prolonged late systolic murmur suggests a more severe degree of stenosis.
    • The murmur is transmitted from the aortic region to the neck and, particularly in elderly persons, towards the apex making it difficult to distinguish from mitral regurgitation.
    • As the valve becomes more stenotic, the closure sound (S2) becomes less audible. If AS is accompanied by aortic insufficiency, a diastolic regurgitant murmur will also be heard. Hypertrophy may lead to atrial gallop (S4).
    • Severe heart failure may render the murmur deceptively faint, or it may become totally inaudible, even in the presence of advanced stenosis.
  • Aortic valve stenosis will be discussed in more detail in a separate article; see Aortic Stenosis.

Mitral regurgitation (MR) and mitral valve prolapse (MVP, Barlow syndrome)

  • Mitral regurgitation is the second most frequent adult valvular disease
  • MR may be caused by abnormalities in the structure of the valve or it may be functional, occurring in most cases as a consequence of LV pumping dysfunction and dilatation.
  • The most common structural defect causing mitral regurgitation is mitral valve prolapse occurring in about 2% of the adult population. The defect is more common in patients with hereditary connective tissue diseases.
  • MVP is often associated with thickening of the mitral valve cusps (at least 5 mm) signifying myxomatous degeneration and predicting worsening MR.
  • Mild functional regurgitation is very common in the elderly and particularly in patients with heart failure.
  • The murmur (Image 1/6)
    • A high pitched pansystolic blowing murmur in the area between the apex of the heart and the mid-axillary line.
    • Prolapse of the mitral valve should be suspected if heart auscultation reveals a high-frequency mid-to-late systolic click or snap. This finding is common (10%) and often innocent.
    • True MVP is associated with a pan- or late-systolic murmur of mitral regurgitation in addition to the potential click (Image 1/7).
    • The murmur of a prolapsed posterior cusp may radiate towards the upper sternum and be mistaken for the murmur of AS.
    • In severe regurgitation, the closure sound (S1) of the valve is often quiet and ventricular gallop (S3) may be audible.
    • The intensity of the murmur does not correlate with the magnitude of regurgitation. If LV contractility is well preserved, the murmur will be loud, and vice versa, as LV contractility decreases so will the intensity of the murmur. A regurgitant murmur caused by papillary muscle damage, resulting from an MI, is usually soft even when the regurgitant volume is large.
    • Mitral regurgitation will be discussed in more detail in a separate article; see Mitral Regurgitation.

Tricuspid regurgitation (TR)

  • TR is almost always afunctional regurgitation in consequence of pressure or volume overload of the right ventricle (such as increased pulmonary artery pressure, atrioseptal defect).
  • Endocarditis associated with illicit drug use as well as iatrogenic causes (pacemaker leads, endomyocardial biopsies) are the most important causes of structural valvular regurgitation.
  • The murmur
    • A pansystolic murmur which resembles the murmur of mitral regurgitation. It is best heard in the fourth intercostal space at the parasternal region. The murmur is augmented by inspiration.
    • Often soft and difficult to hear, even when the echocardiographic findings show large regurgitant flow.
  • Other findings (significant regurgitation)
    • Signs and symptoms of increased venous pressure
    • A prominent systolic venous pulse wave (v wave) in the neck is a typical sign.
    • Ascites, oedema, an enlarged and pulsatile liver
    • Minor regurgitation is a common innocent finding in colour Doppler echocardiography.
    • ECG and chest x-ray: hypertrophy and enlargement of the right ventricle and atrium
  • Oedema and symptoms of right heart failure can be alleviated by giving diuretics.
  • Significant regurgitation can often be fixed by plasty or by valve prosthesis.
  • Catheter-based approaches (such as TriClip® ) have been adopted as the newest form of treatment.

Diastolic murmurs

  • Diastolic murmurs may either be regurgitant murmurs (aortic regurgitation) or flow murmurs (mitral stenosis).
  • They are invariably pathological, even if theunderlying defect is not haemodynamically significant.
  • Diastolic murmurs are often soft. The patient needs to be examined in a quiet room, and particular attention must be paid to listening during diastole.

Aortic regurgitation (AR)

  • AR may be caused by abnormalities affecting the valvular cusps or dilatation of the aortic root and annulus.
    • Degeneration of the cusps andcongenital bicuspid aortic valve are the most common causes of chronic regurgitation.
    • Endocarditis may cause acute worsening of AR.
    • Aortic root dilatation is often caused by connective tissue disease, and aortic dissection may cause severe acute AR.

Signs and symptoms

  • AR remains asymptomatic for a long time; dyspnoea on exertion and tiredness are usually the initial symptoms.
  • Massive acute AR may lead to pulmonary oedema and cardiogenic shock.
  • The murmur (Image 1/9)
    • A "diastolic sighing", blowing murmur, which is heard best with the diaphragm of the stethoscope
    • The murmur is present in the aortic area and towards the apex and is heard best if the patient sits leaning forward and holds his/her breath in expiration. The pitch of the regurgitant murmur is similar to that of breath sounds.
    • As the regurgitation worsens, a systolic ejection murmur will become evident as a result of increased stroke volume, even in the absence of stenosis. An early diastolic murmur alone usually signifies mild regurgitation and a late diastolic murmur more severe regurgitation.
    • The murmur may be difficult to differentiate from breath sounds because of the high pitch.
    • The murmur becomes softer in severe AR associated with heart failure.
    • Ventricular gallop (S3) is a common finding as the ventricle dilates.
  • Other findings
    • High pulse pressure and low diastolic pressure.
    • The pulse wave is forceful and shows a rapid rise and a quick collapse.
    • The apex beat is thrusting and laterally displaced.
    • In mild to moderate AR, the ECG is generally normal, but as the condition worsens signs of LV hypertrophy will usually develop gradually.
    • If chronic regurgitation is significant, a chest x-ray will show cardiomegaly, but in acute AR pulmonary oedema may be the only finding. Dilatation of the ascending aorta may be evident on a chest x-ray.
  • Echocardiography and Doppler examination
    • Echocardiography is the key method for diagnosing the regurgitation and assessing disease severity. More invasive investigations are only rarely required for estimation of the regurgitant volume.
    • Echocardiography is used to evaluate not only the structure and function of the valve but also the width of the aortic root and the size and function of the left ventricle.

Follow-up and management

  • Severe acute AR is a life-threatening condition and urgent surgical intervention is indicated.
  • ACE inhibitors or vasodilating calcium-channel blockers have been used when surgery is contraindicated and, after individual consideration, to improve the patient's haemodynamic profile before proceeding with surgery.
    • Pharmacotherapy has been used particularly if hypertension is a problem, even though evidence on the effect of medication on disease progress remains inconsistent.
  • In significant chronic AR, surgery is indicated as soon as exertional symptoms emerge.
  • Surgery is indicated for asymptomatic patients if LV dilatation is significant (end-diastolic dimension greater than 70 mm or end-systolic dimension greater than 50 mm) or signs of LV dysfunction become evident (EF decreases to < 50%)
  • If the diameter of the ascending aorta increases to more than 45 mm, simultaneous aortic repair is usually indicated.
  • If the diameter of the aortic root increases to 55 mm, surgical treatment is usually indicated independent of the severity of aortic regurgitation.
  • In patients with a connective tissue disease (Marfan syndrome) or bicuspid aortic valve the condition of the aorta should be followed up more intensively and indications for aortic root surgery are less strict.
  • Beta blockers, ACE inhibitors and angiotensin receptor blockers appear to slow down the dilatation of the aortic root in patients with Marfan syndrome. Markedly impaired systolic function of long duration cannot be corrected by surgery.

Systolic and diastolic murmurs

Combined valvular diseases (stenosis and regurgitation within the same valve)

  • Aortic and mitral stenoses do not always occur alone. A diseased stenosed valve may also leak to a variable extent with a resultant murmur during both systole and diastole.
  • In aortic regurgitation, a systolic ejection murmur (usually Grade 2) caused by increased stroke volume is heard in addition to the diastolic regurgitant murmur, even if the valve is not stenotic.
  • A patent ductus arteriosus and coronary artery fistula may cause a continuous systolic-diastolic murmur. The sound of pericardial rub is rhythmic and can often be heard during systole and diastole.
  • Echocardiography is indicated if a new murmur is detected or an existing murmur changes.

Need for additional investigations and referral to specialized care for assessment

  • Differentiation between an innocent murmur and a murmur caused by a cardiac defect is a challenging task.
  • An innocent murmur not requiring further investigation is typically an early-to-mid systolic, Grade 1-2 ejection murmur, heard at the apex or in the left parasternal region, intensified in a sitting up position and without significant radiation.
  • Diastolic and pansystolic murmurs reflect a structural defect. If the cause and severity of the defect are not known, the patient should be referred to a cardiologist for assessment and echocardiography.
  • A large share of prominent (> Grade 2) and widespread murmurs are caused by a valvular disease, and echocardiography is usually indicated to establish the aetiology of the murmur.
  • Even if a murmur is weak it must still always be viewed in relation to the structure of the patient's chest (a murmur is more difficult to hear if the patient is overweight or has emphysema), the symptoms (decreased functional capacity, signs of heart failure) and the patient's overall condition (fever, dyspnoea, hypotension). Even murmurs caused by significant valvular disease, will become more difficult to hear in hypotensive patients with heart failure, and may be masked completely by the crackles of pulmonary oedema.
  • If a murmur intensifies or changes (a new diastolic murmur) as compared with previous records in the patient's notes or findings at the previous checkup, reassessment by repeat echocardiography carried out by a cardiologist is usually necessary.
  • If a patient with known valvular disease presents with fever, the possibility of endocarditis must always be considered in the assessment.
  • Deterioration of the valvular disease must always be borne in mind if there is worsening functional capacity or new onset dyspnoea on exertion, even if no changes can be detected during auscultation and the patient should usually be referred for checkup by a cardiologist.
  • ECG and chest x-ray are routine investigations, but their value in the diagnosis and differential diagnosis of minor valvular disease and murmurs is small.
  • Left ventricular hypertrophy seen in the ECG of a patient with a murmur may be due to significant valvular disease and its cause should be assessed in specialized care.
  • Determination of natriuretic peptides can be carried out to eliminate heart failure. Their concentration is often slightly increased even in minor valvular disease,but the significance of changes in concentrations seen during follow-up is unclear.
  • Exercise ECG is mainly used to evaluate coexisting coronary heart disease and to obtain an objective assessment of exercise capacity when a discrepancy exists between the signs and symptoms or if the patient is normally not physically active.

References

  • Nishimura RA, Otto CM, Bonow RO et al. 2017 AHA/ACC Focused Update of the 2014 AHA/ACC Guideline for the Management of Patients With Valvular Heart Disease: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. Circulation 2017;135(25):e1159-e1195. [PubMed]
  • Baumgartner H, Falk V, Bax JJ ym. 2017 ESC/EACTS Guidelines for the management of valvular heart disease. Eur Heart J 2017;38(36):2739-2791. [PubMed]
  • Arsalan M, Walther T, Smith RL 2nd et al. Tricuspid regurgitation diagnosis and treatment. Eur Heart J 2017;38(9):634-638. [PubMed]
  • Desai MY, Svensson LG. Chronic Severe Aortic Regurgitation: Should We Lower Operating Thresholds? Circulation 2019;140(13):1045-1047. [PubMed]