T2: Heart Sounds Flashcards
Explain the two sounds made by the heart. How do they differ?
S1: “lub”, slightly longer and lower pitch
S2: “dub”, shorter, higher pitch
How is S1 created?
S1=“lub”
- closure of the left and right atrioventricular valve (bicuspid/tricuspid)
How is S2 created?
S2= “dub”
- closure of the pulmonic and aortic valves (semilunar)
What are heart sounds?
brief, transient sounds produced by valve opening and closure
How are heart sounds classified?
- systolic sounds
- diastolic sounds
What do extra heart sounds signify?
disorder
What is an S3 commonly associated with?
- left ventricular failure
- blood from the left atrium slams into an already overfilled ventricle (during early diastolic filling)
What is S4 commonly associated with?
- blood trying to enter a stiff, non-compliant left ventricle during atrial contraction
- associated with left ventricular hypertrophy (long standing hypertension)
Where are heart sounds best heard?
- location (body)
- location (bone)
- side of organism
- under the triceps/elbow
- between the 3rd and 5th intercostal spaces
- on the left side
can also be heard on the right side
What is the normal heart rate?
50 to 80 beats per minute
Explain the auscultations of the heart in a normal animal.
- only the first two sounds heard
- S1: louder, longer
- S2: shortly after S1
Where is S1 loudest?
at the 4th intercostal space
Where is S2 loudest?
at the 3rd intercostal space
What are the four main areas for cardiac auscultation?
- mitrial valve (left atrioventricular valve)
- aortic valve (left 4th intercostal space)
- pulmonic valve (left 3rd intercostal space)
- tricuspid valve (right atrioventricular valve) (3rd-4th intercostal space)
What sound is longer: S1 or S2?
S1
