Murmurs Flashcards
What is a murmur?
A heart murmur is a blowing, whooshing, or rasping sound heard during a heartbeat.
What causes a murmur?
Turbulent (rough) blood flow through the heart valves or near the heart
What are the two subcategories of murmurs?
Systolic murmurs - arterial stenosis and mitral regurgitation
Diastolic murmurs - arterial regurgitation and mitral stenosis
What is a systolic murmur?
This happens during a heart muscle contraction.
Systolic murmurs are divided into ejection murmurs (due to blood flow through a narrowed vessel or irregular valve) and regurgitant murmurs (backward blood flow into one of the chambers of the heart).
What is a diastolic murmur?
This happens during heart muscle relaxation between beats.
Diastolic murmurs are due to a narrowing (stenosis) of the mitral or tricuspid valves, or regurgitation of the aortic or pulmonary valves.
What are the four main types of murmurs to know?
Aortic stenosis
Mitral regurgitation
Mitral stenosis
Aortic regurgitation
What is aortic stenosis?
Aortic stenosis is a narrowing of the aortic valve opening.
What triad of symptoms is aortic stenosis associated with?
Heart failure
Syncope
Angina
Signs on examination of aortic stenosis
Slow rising carotid pulse
Narrow pulse pressure
Heaving, non-displaced apex beat (can be displaced if there is left ventricular hypertrophy)
Ejection systolic murmur
Heard best at the second intercostal space on the right
Can be described as “harsh”
Transmitted well to the carotids
Soft S2 heart sound
Ejection click may be heard in some cases (early systolic)
ECG findings in aortic stenosis
ECG in aortic stenosis can show evidence of left ventricular hypertrophy:
Increased QRS complex voltage
Left axis deviation
Poor R-wave progression
Note that the absence of these ECG findings does not preclude an AS diagnosis.
What is mitral regurgitation?
The backflow of blood across the mitral valve during systole due to incompetence of the mitral valve.
What causes acute mitral regurgitation?
Ischaemic MR - primarily due to papillary muscle rupture secondary to myocardial infarction.
Non-ischaemic MR - ruptured chordae tendineae due to any of a number of causes
Myxomatous disease (mitral prolapse)
Infective endocarditis
Rheumatic heart disease - acute or chronic
Trauma
Spontaneous rupture
Prosthetic valve MR -
Tissue valvelet rupture due to endocarditis, degeneration or calcification
Paravalvular regurgitation due to infection or suture rupture
Valve thrombus or infection causing impaired closure
Is acute MR an emergency?
Acute mitral regurgitation is a cardiac emergency and may present with sudden onset pulmonary oedema, hypotension and cardiogenic shock.
Symptoms such as:
Shortness of breath
Exertional dyspnoea
Fatigue
Weakness
Complications of MR
Heart failure
Thromboembolism secondary to AF
Haemoptysis secondary to pulmonary hypertension and symptoms of right heart failure are possible but less common than in mitral stenosis (MS).
Infective endocarditis and associated symptoms can also complicate M
Examination findings in MR
Systolic murmur
Loudest at the apex
Pansystolic in nature
Radiates to the axilla
S1 may be quiet or absent
If patients are in decompensated heart failure:
Bilateral lung crepitations
Raised JVP
S3/S4
Peripheral/sacral oedema oedema
What is mitral stenosis?
Impaired opening of the mitral valve affecting blood flow from the left atrium to ventricle.
What is the most common cause of mitral stenosis?
Rheumatic heart disease. Streptococcal antigens secondary to bacterial infection cross-react with the valve tissue, causing damage.
Signs of Mitral Stenosis
Mitral facies (malar flush) - cutaneous vasodilation due to carbon dioxide retention
Low volume pulse
Atrial fibrillation
Elevated JVP (prominent ‘a’ wave due to raised right atrial pressure, or absent ‘a’ wave in AF)
Tapping, non-displaced apex beat (palpable S1)
R ventricular heave (suggestive of pulmonary hypertension)
Inspiratory crepitations (pulmonary oedema) and other signs of right heart failure
Cardiac auscultation findings in mitral stenosis
Loud S1 (becomes softer with increasing calcification)
Loud P2 with pulmonary hypertension (later stages S2 split)
Opening snap heard at apex (only with pliable valves)
Diastolic murmur -
Low pitched rumble, most prominent at apex
Loudest in expiration
Heard best with patient lying on left side
Heard best using stethoscope bell (low frequency)
Graham-Steell murmur (early diastolic murmur - only if pulmonary regurgitation present, secondary to pulmonary hypertension)
What is aortic regurgitation?
Reverse flow of blood across the aortic valve in diastole due to the incompetence of the valve
Acute causes of AR
Infective endocarditis and aortic dissection are the most common acute causes of AR.
What are chronic causes of AR?
Calcific aortic valve disease (age related)
Myxomatous degeneration
Congenital disease e.g. bicuspid aortic valve
Rheumatic heart disease - most common cause in the developing world
Infective endocarditis
Rheumatic causes e.g. rheumatoid arthritis, antiphospholipid syndrome
Marfan’s syndrom
