HEART DEFECTS + MURMURS Flashcards
Cause of S1?
Closing of AV valves (tricuspid + mitral) at the start of ventricular contraction.
Cause of S2?
Closing of SL valves (pulmonary and aortic) once systole is complete.
When does S3 happen?
~0.1 seconds after S2.
In which patients is an S3 normal?
Young + healthy 15-40 year olds.
In which patients is an S3 pathological?
In older patients where the ventricles + chordae tendinae are stiff + weak so reach their limit much faster.
This can indicate heart failure.
What causes the S3 sound?
The chordae tendinae being pulled to their full length.
When is S4 heard?
Directly before S1.
What does an S4 indicate?
A stiff or hypertrophic ventricle caused by turbulent flow from an atria contracting against a non-compliant ventricle.
When is an S4 sound pathological?
Always.
The bell of a stethoscope hears what sounds?
Low-pitched sounds.
The diaphragm of a stethoscope hears what sounds?
High-pitched sounds.
What is Erb’s point?
The position in the third intercostal space on the left sternal border which is the best area for listening to heart sounds.
Mneomonic for assessing a murmur?
S - site C - character R - radiation I - intensity P - pitch T - timing
Gradings of a murmur?
- difficult to hear
- quiet
- easy to hear
- easy to hear + palpable thrill
- can hear with stethoscope barely touching chest
- can hear with stethoscope off chest
Mitral stenosis causes what structural change?
left atrial hypertrophy
Aortic stenosis causes what structural change?
left ventricular hypertrophy
Mitral regurgitation causes what structural change?
left atrial dilatation
Aortic regurgitation causes what structural change?
left ventricular dilatation
2 causes of mitral stenosis?
rheumatic heart disease
infective endocarditis
Mitral stenosis murmur?
Mid-diastolic, low-pitched ‘rumbling’ murmur.
Features associated with mitral stenosis?
loud S1
tapping apex beat
malar flush - back pressure of blood into the pulmonary system = rise in CO2 + vasodilation.
AF - left atrium struggles to push blood through stenotic valve = strain + electrical disruption.