Heart murmur resident survival guide

Heart murmur Resident Survival Guide Microchapters
Overview
Causes
Diagnosis
Treatment
Do's
Don'ts

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Nuha Al-Howthi, MD[2]

Synonyms and keywords: Approach to a heart murmur, Heart murmur diagnostic workup

Overview

A Heart murmur is an abnormal heart sound produced as a result of turbulent blood flow, which is sufficient to produce audible noise, defined as a relatively prolonged series of auditory vibrations of varying intensity (loudness), frequency (pitch), quality, configuration, and duration. Murmurs could be systolic or diastolic or continuous murmur.

Causes

Life Threatening Causes

Life-threatening causes include conditions that may result in death or permanent disability within 24 hours if left untreated.

• Papillary muscle rupture complicating acute myocardial infarction
• Rupture of chordae tendineae.
• Infective endocarditis
• Blunt chest wall trauma

Common Causes

• Systolic murmur
  • Ejection murmurs
    • Functional
      • Still's murmur and its adult variant
      • Flow murmur emanating from the root of the pulmonary artery
      • Murmur associated with high cardiac output states
      • Flow murmurs associated with aortic or pulmonary valvular insufficiency
    • Organic
      • Valvular aortic stenosis
      • Aortic sclerosis
      • Discrete subvalvular aortic stenosis (web or tunnel)
      • Supravalvular aortic stenosis
      • Hypertrophic obstructive cardiomyopathy
      • Pulmonary valvular stenosis
      • Pulmonary infundibular stenosis
      • Atrial septal defect
      • Tetralogy of Fallot
  • Regurgitant murmurs
    • Functional: none
    • Organic:
      • Mitral regurgitation:
        • Rheumatic
        • Papillary muscle dysfunction
        • Mitral valve prolapse
        • Acute
      • Tricuspid regurgitation:
        • Chronic
        • Acute
      • Ventricular septal defect
        • Roger's type (small and large)
          • Without pulmonary hypertension
          • With pulmonary hypertension
        • Slitlike
    • Extracardiac sounds simulating systolic heart murmurs
      • Subclavian (supraclavicular/brachiocephalic) Murmur
      • Internal mammary soufflé
      • Carotid artery bruits
      • Coarctation of the aorta
      • Murmurs emanating from a dilated aortic or pulmonary artery root
      • Patent ductus arteriosus with pulmonary hypertension
        
• Diastolic murmur
  • Aortic regurgitation
  • Pulmonary valve regurgitation
  • Mitral rumble
    • Obstruction to flow
      • Mitral stenosis (rheumatic, congenital)
      • Left atrial myxoma
      • Cor triatriatum
      • Localized pericardial constriction
    • Increased flow
      • Mitral regurgitation
      • Ventricular septal defect
      • Patent ductus arteriousus
      • Complete heart block
  • Tricuspid rumble
    • Obstruction to flow
      • Tricuspid stenosis (rheumatic, Ebstein's anomaly, carcinoid)
      • Right atrial myxoma
      • Localized pericardial constriction
    • Increased flow
      • Atrial septal defect
      • Tricuspid regurgitation
• Continuous murmur
  • THORACIC:
    • Precordial
      • Patent ductus arteriosus
      • Coronary arteriovenous fistulas
      • Sinus of Valsalva aneurysm ruptured into right cavities
      • Atrial septal defect associated with abnormalities that cause increased pressure in the left atrium
      • Left coronary artery origin from pulmonary artery anomaly
      • Continuous murmur at intern mammary artery
    • Extra Precordial
      • Coarctation of the aorta
      • Pulmonary atresia
      • Pulmonary arteriovenous fistula
      • Truncus arteriosus
      • Anomalies of origin of the pulmonary artery
  • EXTRATHORACIC:
    • Venous hum
    • Cruveilhier-Baumgarten sindrom
    • Severe arterial stenosis
    • Extrathoracic arteriovenos fistulas

Diagnosis

Shown below is an algorithm summarizing the Approach to the Heart Murmurs according to ACC/AHA 2006 Guidelines for the Management of Patients With Valvular Heart Disease. Abbreviations: AR: Aortic regurgitation, AS:Aortic stenosis, COP:Cryptogenic organizing pneumonia , HOCM:Hypertrophic cardiomyopathy , JVP: Jugular venous pressure , MR:Mitral regurgitation , MVP: Mitral valve prolapse , PAH:Pulmonary hypertension , PR:Pulmonic regurgitation , PS:Pulmonary stenosis , TR: Tricuspid regurgitation , TS: Tricuspid stenosis , TTE:Echocardiography , VSD:Ventricular septal defect

Obtain a Detailed History The history, and associated physical examination findings provide additional clues by which the significance of a heart murmur can be established Accurate bedside identification of a heart murmur can inform decisions regarding the indications for noninvasive testing and the need for referral to a cardiovascular specialist. ❑ Address specific patient symptoms and complaints ❑ Obtain review of systems relevant to Cardiovascular system ❑ Headache ❑ Dizziness ❑ Syncope/presyncope ❑ Chest pain / Angina ❑ Palpitations ❑ Dyspnea ❑ Cough ❑ Abdominal pain ❑ Peripheral edema ❑ Dyspnea on exertion ❑ Fatigue ❑ Orthopnea ❑ Paroxysmal nocturnal dyspnea Past Medical History ❑ History of previous medical diagnoses / past medical complaints / hospitalizations and surgeries ❑ Cardiovascular disease ❑ Hypertension ❑ Bicuspid aortic valve ❑ Rheumatic fever ❑ History of diabetes mellitus Medications ❑ Current prescribed medications ❑ Previous intake of medications and reason for discontinuation ❑ History of drug adverse effects Allergies ❑ Known drug allergies ❑ Known environmental/food allergies Family history ❑ Family history of cardiovascular disease Social History ❑ Overall living situation ❑ Occupation ❑ Exercise ❑ Diet (general) ❑ Smoking history ❑ Alcohol use ❑ Recreational drug use ❑ Stress ❑ Sexual lifestyle & contraceptive methods

Examine the patient: ❑ Pulse Rate, rhythm, and characteristics include contour and amplitude of the pulse like (Water hammer pulse in AR) ❑ Blood pressure ❑ Temperature ❑ Respiratory rate ❑ Skin: ❑ Cyanosis ❑ Peripheral edema ❑ Nails: ❑ Splinter hemorrhages. ❑ Mouth: ❑ Palatal petechiae associated with infective endocarditis. ❑ A high arched palate is associated with congenital heart disease, such as MVP ❑ Neck: ❑ JVP can lead towards diseases such as atrial fibrillation,TR,TS,PAH, PS ❑ Cardiovascular system: ❑ Palpation: includes assessing the arterial pulse, measuring blood pressure, palpating any thrills on the chest, and palpating for the point of maximal impulse. ❑ Auscultation: is the cornerstone, auscultate the four standard positions; supine, left lateral decubitus, upright, upright leaning forward. If a murmur is present, the following features require inspection; timing, location, radiation, duration, intensity, pitch, quality, relation to respiration, and maneuvers such as Valsalva or hand grip. ❑ Respiratory system: ❑ Crackles or rales ❑ Tachypnea ❑ Abdominal system: ❑ Hepatojugular reflex ❑ Hepatomegaly ❑ Ascites

Obtain the whole features of the murmur ❑ The accurate timing of heart murmurs is the first step in their identification. ❑ Duration and Character: The configuration of a heart murmur may be described as crescendo, decrescendo, crescendo-decrescendo, or plateau. ❑ Intensity ❑ The intensity of a heart murmur is graded on a scale of 1–6 ❑ A grade 1 Murmur is very soft and is heard only with great effort. ❑ A grade 2 Murmur is easily heard but not particularly loud. ❑ A grade 3 Murmur is loud but is not accompanied by a palpable thrill over the site of maximal intensity. ❑ A grade 4 Murmur is very loud and is accompanied by a thrill. ❑ A grade 5 Murmur is loud enough to be heard with only the edge of the stethoscope touching the chest. ❑ A grade 6 Murmur is loud enough to be heard with the stethoscope slightly off the chest. ❑ Murmurs of grade 3 or greater intensity usually signify important structural heart disease. ❑ The intensity of a heart murmur may be diminished by any process that increases the distance between the intracardiac source and the stethoscope on the chest wall, such as obesity, obstructive lung disease, and a large pericardial effusion. The intensity of a murmur also may be misleadingly soft when COP is reduced significantly or when the pressure gradient between the involved cardiac structures is low. ❑ Location and Radiation ❑ Recognition of the location and radiation of the murmur helps facilitate its accurate identification. ❑ Adventitious sounds, such as a systolic click or diastolic snap, or abnormalities of S1 or S2 may provide additional clues. ❑ Interventions Used to Alter the Intensity of Cardiac Murmurs’’’ ❑ Respiration: Right-sided murmurs generally increase with inspiration. Left-sided murmurs usually are louder during expiration. ❑ Valsalva maneuver: Most murmurs decrease in length and intensity. Two exceptions are the systolic murmur of HCM, which usually becomes much louder, and that of MVP, which becomes longer and often louder. ❑ Exercise: Murmurs caused by blood flow across normal or obstructed valves (e.g., PS and MS) become louder with both isotonic and isometric (handgrip) exercise. Murmurs of MR, VSD, and AR also increase with handgrip exercise. ❑ Positional changes: With standing, most murmurs diminish, 2 exceptions being the murmur of HCM, which becomes louder, and that of MVP, which lengthens. With brisk squatting, most murmurs become louder, but those of HCM and MVP usually soften and may disappear. Passive leg raising usually produces the same results as brisk squatting. ❑ Pharmacological interventions: During the initial relative hypotension after amyl nitrite inhalation, murmurs of MR, VSD, and AR decrease, whereas murmurs of AS increase. During the later tachycardia phase, murmurs of MS and right-sided lesions also increase. This intervention may thus distinguish the Austin Flint murmur from that of MS. The response in MVP often is biphasic.

Systolic Murmur

Diastolic murmur

Continuous murmur

Early Systolic Murmur ❑ Acute, severe MR ❑ Early, decrescendo systolic murmur best heard at or just medial to the apical impulse. ❑ It could be due to papillary muscle rupture complicating acute myocardial infarction, rupture of chordae tendineae in the setting of myxomatous mitral valve disease,infective endocarditis and blunt chest wall trauma. ❑ TTE is indicated in all cases of suspected acute, severe MR to define its mechanism and severity, delineate left ventricular size and systolic function, and provide an assessment of suitability for primary valve repair. ❑ A congenital, small muscular VSD ❑ The defect closes progressively during septal contraction, and thus, the murmur is confined to early systole. ❑ It is localized to the left sternal border and is usually of grade 4 or 5 intensity. ❑ Signs of pulmonary hypertension or left ventricular volume overload are absent. ❑ Large and uncorrected VSD associated with pulmonary hypertension. ❑ The murmur best heard along the left sternal border but is softer and signs of pulmonary hypertension (right ventricular lift, loud and single S2) may predominate. ❑ Suspicion of a VSD is an indication for TTE. ❑ Tricuspid regurgitation with normal pulmonary artery pressures (due to infective endocarditis). ❑ The murmur is soft (grade 1 or 2), is best heard at the lower left sternal border, and may increase in intensity with inspiration (Carvallo’s sign). ❑ Regurgitant “c-v” waves may be visible in the JVP. ❑ TR in this setting is not associated with signs of right heart failure.

Holosystolic murmur ❑ Chronic mitral regurgitation ❑ The holosystolic murmur of chronic MR is best heard at the left ventricular apex and radiates to the axilla; it is usually high-pitched and plateau in configuration. ❑ In contrast to acute MR, left atrial compliance is normal or even increased in chronic MR. ❑ Chronic severe MR results in enlargement and leftward displacement of the left ventricular apex beat. ❑ Chronic tricuspid regurgitation ❑ The murmur is softer than that of MR. ❑ Loudest at the left lower sternal border, and usually increases in intensity with inspiration (Carvallo’s sign). ❑ Associated signs include c-v waves in the JVP, an enlarged and pulsatile liver, ascites, and peripheral edema. ❑ VSD ❑ The murmur of a VSD is loudest at the mid- to lower left sternal border and radiates widely. A thrill is present at the site of maximal intensity. There is no change in the intensity of the murmur with inspiration. The intensity of the murmur varies as a function of the anatomic size of the defect.

Midsystolic Murmur ❑ Aortic stenosis the most common cause of a mid-systolic murmur in an adult. ❑ The murmur loudest to the right of the sternum in the second intercostal space (aortic area) and radiates into the carotids. ❑ Usually crescendo-decrescendo in configuration. ❑ To differentiate between the apical systolic murmur from MR and AS, the murmur of AS will increase in intensity, in the beat after a premature beat, whereas the murmur of MR will have constant intensity from beat to beat. ❑ In case of severe AS a systolic thrill and a grade 4 or higher murmur could be heard, Other auscultatory findings of severe AS include a soft or absent A2, paradoxical splitting of S2, an apical S4, and a late-peaking systolic murmur. ❑ In children, adolescents, and young adults with congenital valvular AS, an early ejection sound (click) is usually audible, more often along the left sternal border than at the base. Its presence signifies a flexible, noncalcified valve and localizes the left ventricular outflow obstruction to the valvular (rather than sub- or supravalvular) level. ❑ TTE is indicated to assess the anatomic features of the aortic valve, the severity of the stenosis, left ventricular size, wall thickness and function, and the size and contour of the aortic root and proximal ascending aorta. ❑ Hypertrophic cardiomyopathy (HOCM) ❑ The mid-systolic murmur that is usually loudest along the left sternal border or between the left lower sternal border and the apex. ❑ The intensity of the murmur may vary from beat to beat and after provocative maneuvers but usually does not exceed grade 3. ❑ The murmur will increase with reduction in preload or afterload (Valsalva, standing, vasodilators), or with an augmentation of contractility (inotropic stimulation). ❑ The intensity of the murmur decrease with increase in preload (squatting, passive leg raising, volume administration) or afterload (squatting, vasopressors) or reduce contractility (β-adrenoreceptor blockers). ❑ LVH is present on the ECG, and the diagnosis is confirmed by TTE. ❑ MVP behaves similarly to that due to HOCM in response to the Valsalva maneuver and to standing/squatting, these two lesions can be distinguished by the presence of LVH in HOCM or a non ejection click in MVP. ❑ Congenital pulmonic stenosis ❑ The mid-systolic, crescendo-decrescendo murmur is best appreciated in the second and third left intercostal spaces. ❑ The duration of the murmur lengthens and the intensity of P2 diminishes with increasing the degree of stenosis. ❑ An early ejection sound that decreases with inspiration, and heard in younger patients. ❑ A parasternal lift and ECG evidence of right ventricular hypertrophy indicate severe pressure overload. ❑ TTE is recommended for complete characterization. ❑ ASD with left-to-right intra-cardiac shunting ❑ Grade 2–3 mid-systolic murmur at the middle to upper left sternal border with fixed splitting of S2. ❑ TTE is indicated to evaluate a grade 2 or 3 mid-systolic murmur when there are other signs of cardiac disease. ❑ An isolated grade 1 or 2 mid-systolic murmur, heard in the absence of symptoms or signs of heart disease, is most often a benign finding for which no further evaluation.

Late Systolic Murmurs ❑ late systolic murmur that is best heard at the left ventricular apex is usually due to MVP. ❑ The radiation of the murmur can help identify the specific mitral leaflet involved in the process of prolapse. ❑ With posterior leaflet prolapse, the murmur radiates to the base of the heart. ❑ Anterior leaflet prolapse radiates to the axilla or left infrascapular region. ❑ Standing causes the murmur to become louder and longer. With squatting the murmur becomes softer and shorter in duration. ❑ TTE is recommended for assessment of late systolic murmurs.

Early Diastolic Murmurs ❑ AR ❑ High pitched, blowing, decrescendo, early to mid-diastolic murmur, begins after the aortic component of S2 (A2). ❑ Best heard at the second right interspace with the patient leaning forward at end expiration. ❑ With primary valve disease, such as congenital bicuspid disease, prolapse, or endocarditis, the diastolic murmur radiate along the left sternal border. ❑ When AR is caused by aortic root disease, the diastolic murmur may radiate along the right sternal border. ❑ The diastolic murmur of acute,severe AR is notably shorter in duration and lower pitched than the murmur of chronic AR. ❑ chronic severe AR is accompanied by several peripheral signs of significant diastolic run-off. ❑ Pulmonic regurgitation ❑ A decrescendo, early to mid-diastolic murmur (Graham Steell murmur) that begins after the pulmonic component of S2 (P2) ❑ Best heard at the second left interspace, and radiates along the left sternal border. The intensity of the murmur may increase with inspiration. ❑ PR is most commonly due to dilation of the valve annulus from chronic elevation of the pulmonary artery pressure. ❑ To distinguish PR from AR as the cause of a decrescendo diastolic murmur heard along the left sternal border, Signs of pulmonary hypertension, including a right ventricular lift and a loud, single or narrowly split S2, are present with PR ❑ PR in the absence of pulmonary hypertension can occur with endocarditis or a congenitally deformed valve, in this condition the diastolic murmur is softer and lower pitched than the classic Graham Steell murmur. ❑ TTE is indicated for the further evaluation of a patient with an early to mid-diastolic murmur.

Mid-diastolic murmurs ❑ MS ❑ The most common cause of MS is Rheumatic fever, the murmur is low-pitched and is best heard with the bell of the stethoscope when the patient is turned in the left lateral decubitus position. ❑ Loudest at the left ventricular apex. ❑ It is usually of grade 1 or 2 intensity. The intensity of the murmur increases during maneuvers that increase cardiac output and mitral valve flow, such as exercise. An increase in the intensity of the murmur just before S1, a phenomenon known as pre-systolic accentuation. Presystolic accentuation does not occur in patients with atrial fibrillation. ❑ TS ❑ Murmur is best heard at the lower left sternal border and increases in intensity with inspiration. ❑ A prolonged y descent may be visible in the jugular venous waveform. ❑ This murmur is very difficult to hear and often is obscured by left-sided acoustical events. ❑ Large left atrial myxomas ❑ The murmur associated with an atrial myxoma may change in duration and intensity with changes in body position. An opening snap is not present, and there is no pre-systolic accentuation. ❑ Austin Flint murmur ❑ Due to chronic, severe AR is a low-pitched mid to late, grade 1 or 2 diastolic murmur at the apex. ❑ Distinguished from the murmur due to MS by the absence of an opening snap and the response of the murmur to a vasodilator challenge. Lowering afterload with an agent such as amyl nitrite will decrease the duration and magnitude of the Austin Flint murmur. The intensity of the diastolic murmur of mitral stenosis may either remain constant or increase with afterload reduction because of the reflex increase in cardiac output and mitral valve flow. ❑ Severe, isolated TR and with large ASD and significant left-to-right shunting Other signs of an ASD are present including fixed splitting of S2 and a mid-systolic murmur at the mid- to upper left sternal border. ❑ TTE is indicated for evaluation of a patient with a mid- to late diastolic murmur.

Continuous murmur ❑ Begin in systole, peak near the S2, and continue into all or part of diastole. ❑ If the continuous murmur heard at the upper left sternal border, mostly associated with a patent ductus arteriosus. ❑ If the murmur heard at the upper right sternal border, it could be ruptured sinus of Valsalva aneurysm. ❑ A continuous murmur also may be audible along the left sternal border with a coronary arteriovenous fistula.

Strategy for evaluating heart murmurs

Abbreviations: ECG:electrocardiogram

Cardiac murmur

Systolic Murmur

Diastolic Murmur

Continuous Murmur

❑ Midsystolic, grade 2 or less

❑ Early systolic, ❑ Midsystolic grade 3 or more, ❑ Late systolic, ❑ Holosystolic murmur

❑ Venous hum ❑ Mammary souffle of pregnancy

Asymptomatic and no associated findings

❑ Symptomatic or other signs of cardiac diseases, ❑ If an ECG or X-ray has been obtained and is abnormal

No further workup

No further workup

Echocardiography Class I ❑ Echocardiography is recommended for asymptomatic patients with diastolic murmurs, continuous murmurs, holosystolic murmurs,late systolic murmur, murmurs associated with ejection clicks or murmurs that radiate to the neck or back.(Level of Evidence: C) ❑ Echocardiography is recommended for patients with heart murmurs and symptoms or signs of heart failure, myocardial ischemia/infarction, syncope, thromboembolism, infective endocarditis, or other clinical evidence of structural heart disease.(Level of Evidence: C) ❑ Echocardiography is recommended for asymptomatic patients who have grade 3 or louder mid peaking systolic murmurs.(Level of Evidence: C) Class IIa ❑ Echocardiography can be useful for the evaluation of asymptomatic patients with murmurs associated with other abnormal cardiac physical findings or murmurs associated with an abnormal ECG or chest X-ray.(Level of Evidence: C) ❑ Echocardiography can be useful for patients whose symptoms and/or signs are likely non cardiac in origin but in whom a cardiac basis cannot be excluded by standard evaluation.(Level of Evidence: C) Class III ❑ Echocardiography is not recommended for patients who have a grade 2 or softer midsystolic murmur identified as innocent or functional by an experienced observer.(Level of Evidence: C)

Catheterization and angiography if appropriate

Treatment

The management of heart murmurs depend on the underlying cause. Click on each disease shown below to see a detail management for every cause of heart murmur.
Abbreviations: HOCM:Hypertrophic cardiomyopathy

SYSTOLIC MURMUR	DIASTOLIC MURMUR
❑ Acute Mitral Regurgitation ❑ chronic Mitral Regurgitation ❑ Aortic stenosis ❑ HOCM	❑ Aortic regurgitation ❑ Mitral stenosis

Do's

• Order echocardiography for asymptomatic patients with diastolic murmurs, continuous murmurs, holosystolic murmurs, late systolic murmurs,murmurs associated with ejection clicks or murmurs that radiate to the neck or back or murmurs and symptoms or signs of heart failure, myocardial ischemia/infarction, syncope,thromboembolism,infective endocarditis.
• Order Cardiac Catheterization if there is a discrepancy between the echocardiographic and clinical findings.
• Do Serial measurements over time, or reassessment with a different imaging technology (radionuclide ventriculography or cardiac magnetic resonance) to determine surgical recommendations for asymptomatic patients with MR or AR.

Don'ts

• Don't do Echocardiography for patients who have a grade 2 or softer midsystolic murmur identified as innocent or functional by an experienced observer.
• Don't re-place the cardiovascular examination by Echocardiography.