Heart Sounds and Murmers Flashcards
What causes the first (S1) heart sound?
The first heart sound is caused by closure of the mitral and tricuspid valves at the beginning of systole.
What causes the second (S2) heart sound?
The second heart sound is caused by closure of the aortic and pulmonic valves (semilunar valves) at the beginning of diastole.
An S3 heart sound is an indicator of what condition?
An S3 heart sound (gallop rhythm) during mid-diastole is most often heard in the context of systolic heart failure in adults.
What is the postulated mechanism(s) that produces an S3 heart sound?
The third heart sound (S3) is thought to reflect a flaccid and inelastic condition of the heart during diastole. A logical but unproven explanation is oscillation of blood back and forth between the walls of the ventricles initiated by inrushing blood from the atria.
Guyton, Guyton and Hall’s TMP, 14e. p284
Describe the murmur heard in mitral stenosis.
Mitral stenosis is recognized by the characteristic opening snap that occurs early in diastole and by a rumbling diastolic murmur, best heard with the chest piece placed over the cardiac apex.
Describe the murmurs heard in mitral insufficiency.
The cardinal feature of mitral insufficiency is a holosystolic murmur (heard throughout systole), best heard with the chest piece placed over the cardiac apex. The murmur typically radiates into the axilla.
Describe the murmurs heard in aortic stenosis.
Aortic stenosis is recognized by its characteristic systolic murmur, best heard in the second right intercostal space (over the aortic arch) with transmission into the neck, often mimicking a carotid bruit.
Describe the murmurs heard in aortic insufficiency.
Aortic insufficiency is recognized by its diastolic murmur, best heard along the right sternal border.
How is aortic valvular insufficiency graded?
The severity of aortic insufficiency is assessed qualitatively: regurgitation of less than 20% of the total LV stroke volume is considered mild, 20% to 39% is considered moderate, 40% to 60% is considered moderately severe, and more than 60% is considered severe.
What is the problem if the newborn has a systolic and a diastolic murmur?
The patient with patent ductus arteriosus has both a systolic and diastolic murmur. The murmur is more intense during systole than during diastole, creating a machinery murmur.
What should be heard in a patient in congestive heart failure?
An S3 gallop should be heard if the patient is in congestive heart failure. Left-sided S3 is best heard with the bell piece of the stethoscope at the left ventricular apex during expiration and with the patient in the left lateral position. Right-sided S3 is best heard at the left sternal border or just beneath the xiphoid and is increased with inspiration.
