Murmurs Flashcards
What are normal heart sounds?
short: S1 (closure of the mitral and tricuspid valves) and S2 (closure of the aortic and pulmonic valves) - best heard with the diaphragm of the stethoscope
=> S3 and S4 are additional sounds, often pathologic best heard with the bell of the stethoscope
What is a murmur?
a prolonged sound caused by turbulent blood flow over the valves
What is a thrill?
a palpable murmur (4/6 intensity)
What is a bruit?
a murmur that occurs outside the heart (e.g., carotid - risk for stroke; abdominal - risk for renal artery stenosis)
What is S3?
abnormal heart sound heard at the beginning of diastole - occurs when heart is dilated => indicates systolic dysfunction (e.g., CHF)
What is S4?
abnormal heart sound heard at the end of diastole - occurs when the heart is hypertrophic (ventricles are stiff and the muscle is enlarged) => indicates diastolic dysfunction (e.g., long-standing HTN)
What occurs to blood flow in the setting of systolic heart failure?
the weakened heart muscle can’t squeeze as well - less blood is pumped out of the ventricle
What occurs to blood flow in the setting of diastolic heart failure?
the heart muscle is stiff and can’t relax - less blood fills the ventricle
What does the acronym APT M stand for?
names of the valves of the heart - aortic, pulmonic, tricuspid, mitral => aortic and mitral are most important in assessment of murmurs (easiest to hear)
How are heart murmurs classified?
timing (systole or diastole), location (where it is heard the best), shape, radiation, intensity (1-6), response to maneuvers => timing and location are most important
What is the classification system for intensity of heart murmurs?
Grades:
1 - faint (S1/S2 are louder than murmur)
2 - quiet (murmur is as loud as S1/S2)
3 - moderately loud (murmur is louder than S1/S2)
4 - loud with palpable thrill
5 - very loud, with thrill - may be heard with stethoscope partly off the chest
6 - very loud, with thrill - may be heard with stethoscope entirely off the chest
Where is an aortic murmur best heard?
2nd intercostal space at right sternal border
Where is a mitral murmur best heard?
5th intercostal space at the midclavicular line (apex)
What are the causes of the 2 types of systolic murmurs?
=> aortic stenosis - heard at the 2nd intercostal space at right sternal border and radiating to neck
=> mitral regurgitation - heard at the 5th intercostal space at the midclavicular line and radiating to the axilla
What are the causes of the 2 types of diastolic murmurs?
=> aortic regurgitation - heard at 2nd intercostal space at the right sternal border
=> mitral stenosis - heard at the 5th intercostal space at the midclavicular line
What is the result on the heart of volume overload?
dilation
What is the result on the heart of pressure overload?
hypertrophy
What does the acronym MR ASS stand for?
mitral regurgitation/aortic stenosis => systole
What does the acronym MS ARD stand for?
mitral stenosis/aortic regurgitation => diastole
What is the pathology of aortic stenosis?
LV hypertrophy leads to LV diastolic dysfunction - causes a systolic murmur (greatest risk factor = age)
What are the S and S of aortic stenosis?
angina (not enough blood to aorta), syncope, dyspnea, systolic murmur at 2nd intercostal space at right sternal border radiating to neck, S4 commonly heard
What is the pathology of mitral regurgitation?
dilated LA leads to dilated LV and decreased LV function - risk for atrial fibrillation (greatest risk factor = infarction/infection)
What are the S and S of mitral regurgitation?
dyspnea, systolic murmur at the apex radiating to the axilla (dilation of LA and LV leads to elongation of leaflets - may hear a click followed by murmur)
What are the positions of the mitral and aortic valves during diastole (S2) in a normal heart?
mitral open, aortic closed
What are the positions of the mitral and aortic valves during systole (S1) in a normal heart?
mitral closed, aortic open
What is the pathology of aortic regurgitation?
LV dilation (due to volume overload) leads to LV dysfunction (greatest risk factor = infarction, ischemia, infection)
What are the S and S of aortic regurgitation?
dyspnea (CHF), diastolic murmur at the right sternal border), widened pulse pressure, S3 is also commonly heard
What is the pathology of mitral stenosis?
hypertrophic LA leads to pulmonary congestion/atrial fibrillation (greatest risk factor = Strep infection, pregnancy - due to volume overload)
What are the S and S of mitral stenosis?
dyspnea, palpitations, low pitch diastolic rumble at the apex, atrial fibrillation,
How do you distinguish between murmur due to aortic stenosis and that due to hypertrophic obstructive cardiomyopathy?
aortic stenosis:
=> Valsalva/standing (decreased venous return to the heart) - murmurs will be softer
=> squatting/laying down (increased venous return to the heart) - murmurs will be louder
HOCM:
=> Valsalva/standing - murmurs will be louder
=> squatting/laying down - murmurs will be softer
What are the S and S of hypertrophic obstructive cardiomyopathy?
syncope during exercise, sudden death, harsh systolic murmur that radiates to carotid artery (best heard at right sternal border), murmur gets louder with Valsalva/standing
What are the characteristics of innocent murmurs?
physiologic/flow murmurs; no structural pathology; associated with physical activity, fever (hypermetabolic state), anemia (decreased RBCs means blood is less viscous and moves faster), hyperthyroidism (hypermetabolic state), and pregnancy (volume increase); grade 1-3 (no thrill, always soft); always systolic (never diastolic), softer with standing/Valsalva; no radiation; always asymptomatic; common in children/young adults
What are the characteristics of pathological murmurs?
structural pathology (stenosis or radiation); diastolic/holosystolic/continuous; grade > 3; radiate beyond precordium; associated with symptoms
What is the approach to assessing murmurs?
=> innocent - observe and re-evaluate
=> pathological - evaluate using transthoracic ECHO first => proceed with trans-esophageal ECHO then cardiac catheterization, if needed
What is hypertrophic obstructive cardiomyopathy?
hypertrophy of the septum, not the whole ventricle - blocks blood passage through the aortic valve => no blood flow between the LV and aorta - death due to ischemia-induced ventricular arrhythmia during exertion
What is pathway as blood passes through the heart?
superior vena cava => RA => tricuspid valve => RV => pulmonic valve => pulmonary artery => lungs => pulmonary vein => LA => mitral valve => LV => aortic valve => aorta
What is the pathophysiology of stenosis and regurgitation ?
stenosis <=> hypertrophy
regurgitation <=> dilation
