Heart sounds and ECGs Flashcards
Explain the 3rd heart sound and ddx
Due to rapid ventricular filling
May be normal if
Think volume overload
Causes: congestive cardiac failure, MR, AR, large anterior MI
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Explain and list causes for 4th heart sound
Due to poorly compliant ventricle
Always abnormal
Cannot occur in AF (requires atrial contraction)
Think pressure overload
Causes: AS, HTN, HOCM, post MI fibrosis
![](https://s3.amazonaws.com/brainscape-prod/system/cm/168/611/781/a_image_thumb.png?1447589296)
Causes of mitral stenosis
Rheumatic heart disease (99%)
Causes of mitral regurgitation
RHI
IE
Valve prolapse
Papillary muscle rupture (e.g. MI)
LV dilation
Marfan’s
SLE
Causes of aortic stenosis
RHD
Calcified bicuspid valvve (age 50-60)
Calcified tricuspid valve (aged 70+)
Causes of aortic regurgitation
RHD
IE
Syphilis - luetic heart disease
Bicuspid valve
Hypertension
Aortic dissection
Marfan’s
RA
Ankylosing spondylitis
The absence of P-waves and an irregular rhythm would suggest a diagnosis of…..
Atrial fibrilation
How do you calculate HR from an ECG
Count the number of large squares in an RR-interval - Divide 300 by this number.
E.g. If there were 3 large squares in an R-R interval - 300/3 = 100bpm
What would it suggest if lead I became more positive than lead II and lead III became negative?
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Left axis deviation
What would it suggest if lead I became negative, and lead III became more positive than lead II?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/168/612/558/q_image_thumb.jpg?1447590910)
Right axis deviation
A fixed prolonged PR interval is seen in what?
FIRST DEGREE AV BLOCK
ST-depression classically suggests…
Myocardial ischaemia
If a patient had an abnormally short PR-interval what would be a likely cause?
Wolf Parkinson White syndrome
A short PR-interval indicates abnormally short conduction time between the atria and ventricles. This is caused by the presence of an accessory pathway between the atria and ventricles. Wolf parkinson white syndrome is an example of this kind of disorder. In WPW the an accessory pathway known as “the bundle of kent” is present. Most individuals are asymptomatic however there is a risk of sudden death.
What view of the heart do leads II, III, aVF represent?
Inferior
What is a common cause of right axis deviation?
Right ventricular hypertrophy