Heart sounds Flashcards
What causes the first heart sound?
Closure of mitral and tricuspid valves - start of ventricular systole
What causes the second heart sound?
Closure of the aortic and pulmonary valves - end of ventricular systole
Atrial systole occurs when?
Just after ventricular diastole
What happens at the same time as first heart sound (lub)?
Aortic and pulmonary valves open - not usually heard
What happens at the same time as second heart sound?
Mitral and tricuspid valves open - not usually heard
What is atrial systole heard as?
Not usually heard but if it is, 4th heart sound
When does atrial systole occur?
Just after ventricular diastole
Atrial systole is responsible for what percentage of the cardiac output?
20%
In atrial fibrillation, 20% of CO is…
missing because there is no synchronised atrial systole
A fourth heart sound is…
always abnormal, usually low pitched
from atrial contraction into a non-compliant/ hypertrophied ventricle
What are the causes of fourth heart sounds
Heart failure - atria contracting against thickened heart muscle/ increased pressure
Myocardial infarction
Cardiomyopathy
Hypertension (pressure overload)
How does a fourth heart sound sound?
Le lub dub
How does the third heart sound sound
Lub de dub
A third heart sound is…
A ventricular sound: blood rushing in during rapid filling phase of early diastole
normal in children and young adults up to the age of 30
stiff or dilated ventricle reaches its elastic limit and decelerates the incoming rush of blood
Causes of a pathological third heart sound
Heart failure
Myocardial infarction
Cardiomyopathy
Hypertension - pressure overload
Mitral and aortic regurgitation (volume overload)
Constrictive pericarditis - heart relaxation is restricted due to fibrotic tissue pushing backwards
Five signs of endocarditis:
2 in the hands - clubbing, splinter haemorrhages
1 in the heart - changing murmurs
2 in the abdomen - splenomegaly (b/c subacute infection 6-8w - the time taken for vegetation to develop on valve) & microscopic haematuria
Rare signs of endocarditis
Osler’s nodes
Roth
Janeway lesions
Stages of clubbing
Increased fluctuancy of nail bed
Loss of angle
Increased curvature of nail bed
Expansion of the terminal phalanx
What are the causes of splinter haemorrhages?
Most common = micro-trauma
2nd = endocarditic/vasculitic
On general examination look for:
ABC - anaemia, breathlessness, cyanosis
Hands - splinters & clubbing
Pulses - radial, brachial - rate, rhythm, character, volume
Collapsing pulse test
Ask for or measure BP
Neck for collapsing pulse (Corrigan’s sign)
Then JVP
Assessing JVP
Neck relaxed as internal jugular behind the sterno-mastoid which should be relaxed
Look from front and side
Looking for a pulsation not a visible vein
JVP usually has a double pulsation compared to arterial pulse - may appear to be flickering
If raised, check for sacral or peripheral oedema - sign of R. sided HF
Examining praecordium
Look for scars
Apex beat - position and character
Left parasternal area - for right ventricular impulse
Check for thrills
Auscultation - bell and diaphragm from apex to neck
Patient on left side with the bell for MS
Patient sitting forward, at the end of expiration using diaphragm for AR
