3.2.1. Heart Sounds Flashcards
How do you properly use the Bell on your stethoscope? Do we use it for high or low frequency sounds?
Bell = apply LIGHTLY. Used for low-frequency sounds (not a lot of gallops (S3, S4), rumbling of mitral stenosis)
How do you properly use the Diaphragm on your stethoscope? Do we use it for high or low frequency sounds?
Diaphragm = used for everything else – can’t pick up low freq sounds like gallops or rumbling
What are the proper auscultation areas and where are they?
Aortic: 2nd Right Intercostal Space (RICS)- (sternal border) Pulmonic: 2nd LICS (sternal border) Tricuspid: lower left sternal border (LLSB) Listen here for VSDs Apex: wherever you feel the PMI best; varies from person to person, but typically along the midclavicular line Mitral closure and murmurs can be felt here
What is the S1 and what can happen to it?
MV and tricuspid valve closure; the MV closes before the tricuspid, so S1 may be split.
What is the S2 and what can happen to it?
Aortic and pulmonary valve closure; the AoV closes before the pulmonic valve; inspiration causes increased splitting of S2.
When does S3 occur and what may it indicate?
During rapid ventricular filling (early diastole); normal in children, in adults, associated with dilated ventricles (i.e., dilated CHF) and increased filling pressures.
When does S4 occur and what may it indicate?
Late diastole; not audible in normal adults; its presence suggests high atrial pressure or a stiff ventricle (i.e. ventricular hypertrophy). The left atrium must push against a stiff LV wall (“atrial kick”).
What are all heart sounds due to?
HEART SOUNDS ARE ALL DUE TO VALVE CLOSURE
opening of valves is normally a silent event, but can have sound ass’d w/ejection
What does isovolumetric Contraction mean in the heart?
- Isovolumic contraction: no blood enters or leaves the ventricles
- UNTIL the pressure in the LV is made greater than the aorta
- The opening of the semilunar valve is SILENT – when blood in the aorta begins to flow backward, the aortic semilunar valves SHUT and generate S2
Where can you hear a normal S2 split?
An audible splitting (“ba-dah” sound, split second apart) can be heard at the pulmonic area
What might a loud P2 indicate? (P2 = S2 as heard at pulmonic area)
- Loud P2 (you can hear it OUTSIDE of the pulmonic area)
- typically means pulmonary hypertension
- systolic BP in pulm artery >50 mmHg
- ass’d with:
- left heart failure
- mitral valve disease
- pulmonary arteriolar constriction
- pulmonary vessel occlusion (thrombus, tumor, other…)
What might a single S2 sound indicate?
single S2 = A2 or P2 missing
What might a widened S2 split mean?
- Delayed activation of RV (right bundle branch block, or RV overload from pressure/volume)
- The delay in RV emptying causes a delayed pulmonic sound (P2) that is independent of breathing.
- The RV is late to begin with, so it’ll be even more delayed b/w sounds
What might paradoxical splitting of S2 mean? What is paradoxical S2 splitting?
(P2 comes before A2 – reversed order (due to delayed aortic valve closure))
Seen with any condition in which LV emptying is delayed (aortic stenosis, left bundle branch block). Inspiration causes the delayed A2 and earlier P2 sounds to move closer, effectively eliminating the split.
What is an atrial septal defect? How common is it?
- ASD- atrial septal defect = hole in wall between atria
- Relatively common problem that can lead to irreversible heart/lung damage if left untreated
- 1% of population born w/this
What can an ASD lead to?
- Leads to RV volume overload
- Prolongs RV systole
- Widely splits S2 due to delay in P2
- PERSISTENT, FIXED SPLITTING of S2 (won’t change sound during breathing in or out) – classically diagnostic of ASD
What happens with an ASD during inspiration?
- Sucking blood back into the RA from the LA because of the pressure differential during INSPIRATION
- Also decreases the loading of the LV
- Increased volume on the right will also delay pulmonic closure
What happens to an ASD during expiration?
- During EXPIRATION
- Intrathoracic pressure is positive, so blood is squeezed out of the pulmonary veins, into the LA, and shunted preferentially into the RA and RV because they’re more compliant to changes in pressure
- This allows the RV to fill to its proper capacity just like normal