Resident Editor: Saate Shakil, MD

Faculty Editor: Atif Qasim, MD, MSCE

Background

• The goal is to diagnose structural heart disease before the patient develops irreversible ventricular dysfunction or pulmonary hypertension, which can occur prior to the onset of symptoms
• Determine if murmur is new – ask patient, review chart

Differential Diagnosis

A. Midsystolic (ejection) murmurs – stenotic semilunar valves, outflow tract obstruction; usually crescendo-decrescendo “diamond-shaped” murmurs

• Aortic sclerosis – normal carotid pulse and S2, no radiation, marker of atherosclerotic disease
• Aortic stenosis – radiates to carotids, pulsus parvus  et tardus, soft or absent A2 due to valve calcification, paradoxical S2 splitting, sustained PMI; longer and late-peaking correlates with more severe aortic stenosis
• HOCM – ↑ on standing from squatting (opposite in aortic stenosis) and on Valsalva strain (the latter is less sensitive), ↓ on passive leg raise and hand grip, double carotid pulse
• Pulmonic stenosis – rare in adults, harsh murmur heard at LUSB, can have widely split S2 with soft P2 or single S2; murmur increases with inspiration

B. Holosystolic murmurs

• Mitral regurgitation – best heard at apex with diaphragm, radiates to L axilla, back and occasionally to LUSB, “blowing”, hyper-dynamic PMI; not all MR is holosystolic (e.g., MV prolapse which is mid to late systolic when MR is not severe)
• Tricuspid regurgitation – LLSB, ↑ with inspiration (vs. MR), large c-v wave, right-sided S3, pulsatile liver; murmur may be absent in severely dilated RV (wide open TR)
• Ventricular septal defect – at lower sternal borders, usually loud and harsh; murmur may be absent by the time Eisenmenger syndrome develops

C. Diastolic murmurs – all are pathologic and need evaluation with TTE

• Aortic regurgitation – upper sternal borders, ↑ with sitting forward in full expiration, wide pulse pressure (if severe, chronic), can have associated mid-diastolic/pre-systolic murmur at apex (Austin-Flint); acute AR (e.g. dissection, endocarditis) may only have soft S1 as only finding on auscultation and absence of the peripheral findings seen in chronic AR
• Mitral stenosis – best heard with bell at PMI, loud S1, +/- opening “snap”, left lateral decubitus position, low-pitched “rumble”, severity proportional to duration, associated with rheumatic heart disease
• Tricuspid stenosis – extremely rare, loud S1, mid-diastolic, pulsatile liver, increases with inspiration, opening “snap,” associated with rheumatic heart disease and right atrial myxoma
• Pulmonic regurgitation – early decrescendo, heard at LLSB, similar in character to AR, can be heard in pulmonary hypertension

D. Miscellaneous murmurs

• Innocent/Benign – early systolic, grade 1-2 by definition, absence of other findings, usually best heard at base or lower sternal borders
• Physiologic – early systolic, crescendo-decrescendo, heard at LUSB (RV outflow) or LLSB and apex (LV outflow), due to ↑ stroke volume (fever, anemia, thyrotoxicosis, AV fistula, pregnancy or bradycardia)
• Mitral valve prolapse – mid to late systolic, mid-systolic click, at apex, regurgitant murmur; valsalva makes click earlier and the associated MR murmur longer. Handgrip makes louder.
• Atrial septal defect – diastolic rumble, fixed splitting of S2, LUSB flow murmur across PV.
• Atrial myxoma – changes with position, mid-diastolic or systolic, most common murmur is MS
• Continuous murmurs – PDA, coronary AV fistula, anomalous LCA from PA, PA branch stenosis, aortic-atrial fistula, mammary soufflé, cervical venous hum, bronchial collaterals

Evaluation

• History – chest pain, palpitations, syncope, SOB, DOE, PND, orthopnea, edema, cough, hemoptysis, fever, country of origin, IVDU
• Physical – assess PMI (location, hyper-dynamic vs. sustained), pulse pressure, rhythm, carotid pulsations, JVP, rales, edema, clubbing
• Labs/studies – not routine, but if suspicious for physiologic murmur then consider TSH, CBC, urine pregnancy test; consider EKG (chamber enlargement, ischemia, heart block) and CXR (chamber enlargement).
• Echocardiogram – class I indications include signs/symptoms of heart failure, ischemia, syncope, thromboembolism, infective endocarditis, and asymptomatic patients with diastolic, continuous, and holo- or late-systolic murmurs, murmurs with associated ejection clicks, radiation to neck/back, or louder than grade 2. Class IIa indications include asymptomatic patient with abnormal EKG or CXR.
• Exercise testing – Class IIa indications include asymptomatic patients with severe valvular disease to confirm absence of symptoms, assess hemodynamic response to exercise, and determine prognosis.

Treatment

• Generally focuses on treatment of underlying valvular/structural lesion if present
• Rheumatic heart disease – Class I indication for secondary prevention of rheumatic fever indicated in patients with rheumatic heart disease, specifically MS
• Antibiotic prophylaxis – no Class I indications; prophylaxis not recommended for non-dental procedures in the absence of active infection (e,g., TEE, EGD, colonoscopy, cystoscopy).
  • Prophylaxis is reasonable in the setting of dental procedures for the following patients:
    • prior infectious endocarditis;
    • prosthetic valves (including transcatheter valves);
    • congenital heart disease (CHD) with prosthetic material or large shunts
    • heart transplants with valvular regurgitation from an abnormal valve
  • Give single dose 30-60 min before procedure of amoxicillin 2gm; if cannot tolerate PO, then ampicillin 2g, cefazolin 1g, or CTX 1g; if PCN/cephalosporin contraindicated, then clindamycin 600mg, azithromycin 500mg, or clarithromycin 500mg
• In patients with valvular atrial fibrillation (i.e., rheumatic mitral stenosis), warfarin is the only recommended anticoagulant, not a DOAC
• Can use a direct oral anticoagulant (DOAC) as an alternative to warfarin in patients with atrial fibrillation who require anticoagulation with concomitant native aortic valve disease, tricuspid valve disease, or mitral regurgitation – these patients were included in the trials comparing warfarin with DOACs (ROCKET-AF, ARISTOTLE, RE-LY)

When to refer

• Generally when TTE indicates significant abnormal valvular lesion (usually more than moderate stenosis or regurgitation) or structural heart lesion (congenital lesions beyond PFO or small ASD, cardiomyopathy, significant pulmonary hypertension, pericardial disease)
• More urgent referral if symptomatic

References

Etchells E, et al. Does this patient have an abnormal systolic murmur? JAMA.1997; 277:564-71. Nishimura RA, et al. ACC/AHA 2008 guideline update on valvular heart disease: focused update on infective endocarditis. Circulation. 2008; 118:887-896.

Nishimura RA, et al. ACC/AHA 2014 guideline for the management of patients with valvular heart disease. Journal of Thoracic and Cardiovascular Surgery. 2014; 148:e1-e132. Nishimura RA, 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. J Am Coll Cardiol 2017;Mar 15:[Epub ahead of print].

Wilson W, et al. Prevention of infective endocarditis. Circulation. 2007; 116:1736-1754.