Auscultation Flashcards
What is the first heart sound (S1) caused by?
The shutting of mitral and tricuspid valves
What does the first heart sound signal?
The beginning of systole
What do systole and diastole mean?
Systole = contraction Diastole = relaxation
What is the second heart sound (S2) caused by?
The closure of the aortic and pulmonary valves
What does the second heart sound signal?
The end of systole and the beginning of diastole
What type of murmur coincides with the carotid pulse?
systolic murmurs
What type of murmur does not coincide with the carotid pulse?
Diastolic murmurs
Where can you best hear the physiological splitting of the 2nd heart sound?
The pulmonary area: left 2nd intercostal space at the sternal border DURING INSPIRATION
What causes the physiological splitting of the 2nd heart sound?
Inspiration causes a drop in intrathoracic pressure.
Resulting in increased venous return to the RHS of the heart.
This increased volume prolongs right ventricular ejection time.
Thus the pulmonary component of the 2nd heart sound may be delayed after the aortic component during inspiration.
In the physiological splitting of the 2nd heart sound which component is louder?
The first/aortic
What causes a 3rd heart sound?
The acceleration and deceleration of blood during early passive filling of the ventricle
What is a 3rd heart sound?
An early diastolic low frequency filling sound
When does a 3rd heart sound occur?
Immediately after the 2nd heart sound
Where is the 3rd heart sound best heard?
At the apex with the bell of the stethoscope
What is the pathology for a 3rd heart sound?
Left ventricular systolic dysfunction
If a 3rd heart sound is heard in an older patient what should you do?
Refer them for an echocardiography to assess left ventricular performance
What is a 4th heart sound?
Late diastolic low frequency filling sound
When does the 4th heart sound occur?
Shortly before the first heart sound
What causes a 4th heart sound?
Atrial contraction causing rapid blood flow into a stiff ventricle
What are common causes of a stiff ventricle?
Myocardial ischaemia, hypertension, aortic stenosis
Where is the 4th heart sound best heard?
At the apex with the bell of the stethoscope
What should you do with a patient with hypertension, aortic stenosis or other heart disease who has a 4th heart sound?
Refer for echocardiography to assess the degree of left ventricular hypertrophy and/or aortic stenosis
What is a cardiac murmur caused by?
Turbulent blood flow in the heart
What should a full description of a cardiac murmur include?
Intensity (grading) Character and pitch Timing Location Radiation
What causes an innocent cardiac murmur?
turbulence of blood in the right ventricular outflow tract
What type of murmur is an innocent cardiac murmur: systolic or diastolic?
Systolic
When is an innocent cardiac murmur loudest?
When the circulation is hyperdynamic (eg: in fever, pregnancy, anaemia, thyroxicosis)
What are the characteristics of an innocent cardiac murmur?
Soft mid systolic Usually heard in the pulmonary area Localised to one auscultatory area No radiation No other cardiac abnormalities
What causes a pathological cardiac murmur?
Turbulence of blood due to a structural cardiac abnormality
What are the characteristics of a pathological murmur?
Diastolic murmurs = always pathological
Ejection systolic especially late peaking and pan systolic murmurs are often pathological
Not localized - may be audible in >1 auscultatory area
May radiate
May have associated abnormalities
Where might a pathological murmur radiate to?
the neck in aortic stenosis or to the axilla in mitral regurgitation
What associated abnormalities (symptoms/signs) might you get with a pathological murmur?
Low volume pulse
Thrills
Palpable heaves
Displaced apex
