Lec 6 Auscultation and Heart Sounds Flashcards
What does the P wave signify?
atrial depolarization
When does atrial contraction normally occur?
last third of diastole
What does the QRS complex signify?
ventricular depolarization
Which is relatively louder in males and females, S1 or S2?
in females: S1>S2
in males: S2>S1
What is the significance of the length of PR interval?
determines softness of loudness:
long PR interval- soft sound
short PR interval- loud sound
What does an abnormally loud S1 indicate?
early rheumatic mitral stenosis, hyperkinetic states
What does an abnormally soft S1 indicate?
late mitral stenosis, contractile dysfunction, beta-adrenergic receptor blockade
When does physiologic splitting occur?
during inspiration
What are the possible causes of wide splitting between S1 and S2
right bundle branch block, severe pulmonary hypertension, pulmonic stenosis
What are the possible causes of a delay in A2 (paradoxical splitting)
left bundle branch block, aortic stenosis, left ventricular dysfunction, left hypertrophic cardiomyopathy
What heart condition causes a fixed/persistent splitting upon auscultation?
ASD
What heart condition causes an ejection sound to be heard upon auscultation?
bicuspid semilunar valves, stenotic semilunar valve
factors that decrease LV volume
standing, amyl nitrate
factors that increase LV volume
squatting, phenylephrine
What causes an opening snap to be heard?
stenosed AV valve (usually mitral)
Where is an opening snap sound best heard?
slightly medial to cardiac apex
How is the A2-OS interval related to the severity of stenosis?
A2-OS interval is inversely proportional to the severity of stenosis
How can OS be differentiated from split S2?
- OS does not vary with respiration
2. Split S2 is normally confined to 2nd ICS while OS radiates to a larger area over the left sternal border
What is the significance of a pericardial knock?
abrupt cessation of ventricular expansion after tricuspid valve opening (corresponds to an exaggerated y descent in JVP)
Which heart sounds are part of the so-called gallop rhythm?
S1, S2, and possibly S3 and/or S4
What is the significance of a S3 sound?
abrupt cessation of ventricular distention; oscillation of blood between the ventricular walls
What is the cut-off age for determining whether a S3 sound is physiologic or pathologic?
40
What is the significance of a S4 sound?
turbulence in blood flow in the ventricle due to forceful atrial contraction (indicates a ventricular compliance problem)
In what position is the S4 sound best heard?
cardiac apex on left lateral decubitus position
