08-19-2018, 07:30 PM
Heart murmurs can be recognized by:
• Identifying which auscultation area produces the loudest murmur (review Auscultation Areas)
• Identifying whether it is systolic or diastolic
• Identifying whether it is left or right sided (increased intensity on inspiration if right sided)
• Effect of maneuvers (squatting, standing, the valsalva maneuver, and hand gripping, etc.)
Systolic murmurs:
• Aortic/Pulmonic Stenosis
• Mitral/Tricuspid Regurgitation
• Mitral Valve Prolapse
• Ventricular Septal Defect
Diastolic murmurs:
• Aortic/Pulmonic Regurgitation
• Mitral/Tricuspid Stenosis
Think “sten-O-sis”: problem with valve Opening so that murmurs secondary to stenosis occur when the involved valve is opening (i.e. aortic valve opens in systole, thus aortic stenosis is a systolic murmur).
Aortic stenosis is associated with a crescendo-decrescendo systolic ejection murmur radiating to the carotids.
Triad of SAD symptoms:
• Syncope (decreased blood flow to brain)
• Angina (decreased blood flow through coronary arteries in diastole)
• Dyspnea
Aortic stenosis and prosthetic heart valves may cause macroangiopathic hemolytic anemia secondary to mechanical destruction.
“Pulsus parvus et tardus”: pulses are weak and late compared to heart beat due to outflow obstruction secondary to a stenotic aortic valve
Causes of aortic stenosis:
• Congenital bicuspid aortic valve with superimposed calcification
• Commonly in patients 60 years of age
• Chronic rheumatic fever
An increase in the intensity of the murmur in aortic stenosis is associated with increased preload and decreased afterload. In contrast, increased afterload leads to a decreased pressure gradient between the left ventricle and the vasculature, which results in less blood being expelled and a softer murmur.
Aortic regurgitation is an early, high pitched "blowing" diastolic murmur.
An aortic regurgitation murmur results from ejected blood from the aorta back into the left ventricle during diastole. This decreases peripheral arterial diastolic pressure and leads to an increased LVEDV (left ventricular end-diastolic volume). The Frank-Starling mechanism causes a resulting increase in stroke volume during systole. This increase in systolic pressure leads to an increased pulse pressure.
Aortic regurgitation commonly arises following dilation of the aortic root. Many disease process can cause this including:
• Non-dissecting aortic aneurysm (cystic medial necrosis of Marfan’s syndrome)
• Tertiary syphilis
• Coarctation of the aorta
• Takayasu arteritis
• Aortitis in ankylosing spondylitis
• Endocarditis
• Rheumatic fever
• Bicuspid aortic valve
Clinical signs commonly associated with aortic regurgitation:
• Head bobbing (the force of the systolic pressure with each heartbeat causes the head to bob)
• Pulsating nail bed (pulsations are visible in the nail beds due to the widened pulse pressure)
• Water hammer pulse (bounding and forceful pulse that is commonly associated with widened pulse pressure)
Aortic regurgitation murmur:
Animated Aortic Regurgitation Murmur
Mitral prolapse is a systolic murmur with mid systolic click due to excess valvular tissue prolapsing into the left atrium
Decreased preload causes the murmur to occur earlier, or move closer to S1.
In myxomatous degeneration of mitral valve the valve is thicker but weaker due to an increase in spongiosa (composed of dermatan sulfate) and a decrease in fibrosa (which has more tensile strength).
Mitral valve prolapse associated with genetic disorders:
• Marfan’s syndrome
• Ehlers-Danlos syndrome
• Autosomal dominant polycystic kidney disease
• Fragile X syndrome
• Klinefelter syndrome
Mitral valve prolapse:
Mitral valve prolapse (mid-systolic click) audio
Mitral stenosis is heard as an opening snap followed by mid- to late-diastolic rumbling.
Mitral stenosis is commonly due to prior rheumatic heart disease.
Mitral Stenosis leads to left atrial dilation and hypertrophy. This can result in atrial fibrillation, which is associated with stasis and thrombus formation leading to possible embolization.
Mitral stenosis can lead to left-atrial dilation and hypertrophy which compresses the esophagus and lead to dysphagia for solids.
Mitral stenosis murmur:
Animated Mitral Stenosis Murmur
Mitral regurgitation: holosystolic high pitched "blowing" murmur, heard loudest at the apex, radiates to the axilla.
Acute mitral regurgitation results in increased left atrium pressures and pulmonary congestion.
In chronic mitral regurgitation the left atrium compensates to the increased volume by dilating and increasing compliance which leads to increased incidence of fibrillation rhythms.
Causes of mitral regurgitation:
• Papillary muscle damage post MI
• Mitral valve prolapse/hypertrophic cardiomyopathy
• LV dilation with stretching of mitral valve ring
• Rheumatic heart disease
• Infective endocarditis with valvular damage
• Tuberous sclerosis
Mitral regurgitation murmur:
Animated Mitral Regurgitation Murmur