Heart Sounds Flashcards
What causes the first heart sound (S1)?
Closure of mitral and tricuspid valves
What causes the second heart sound (S2)?
Closure of the aortic and pulmonary valves
What causes the third heart sound (S3)?
Rapid filling of ventricles during diastole
When does the third heart sound occur?
Near beginning of diastole
When can S3 be physiological?
Youth
Trained athletes
Pregnancy
When can S3 be pathological?
If new over 40, indicates heart failure or volume overload
Where and with what part of the stethoscope is S3 best heard?
Bell (low-frequency)
Apex
What word can describe the timings of S1, S2 and S3?
Ken - tuck - y
S1 S2 S3
When does the 4th heart sound occur?
Late diastole (just before S1)
What word can describe the timings of S4, S1 and S2?
Ten ne see
S4 S1 S2
How to remember what heart sound comes first?
Starts with systole (mitral and tricuspid close) therefore starts with S1
Because systolic BP is written down before diastolic BP
What causes S4?
Atrial contraction forcing blood into a non-compliant ventricle (stiff or hypertrophic)
Where is S4 best heard?
Cardiac apex, bell of stethoscope
What type of gallop rhythm is S3 usually described as?
Ventricular gallop
What type of gallop rhythm is S4 usually described as?
Atrial gallop
