ECG: very important, you have to know duration and amplitude of any wave, segment or interval
Anterior lead:V1-V5 lateral leads: I, aVL, V5 and V6 inferior leads: II, III, aVF
Posterior: V1 Septal leads: V1-V3
Exercise ECG, positive if ST elevation, depression>1mm, fall in Blood pressure or arrhythmias and its contraindicated in sever AS or HOCM ,MI within last week or unstable angina and in malignant HTN
The second heart sound comprises of aortic (A2) and pulmonary (P2) component. In LBBB, the aortic closure is delayed because the left ventricle contracts later. This then causes reversed splitting (A2P2 → P2A2) if the second heart sound.
LBBB and left heart strain in HCM and aortic stenosis can cause reversal of A2P2 second heart sounds. Also, in type B wolf parkinson white syndrome, early activation of the right ventricle through an accessory pathway can cause P2 to close prematurely. Patent ductus arteriosus is another cause.
The third heart sound is caused by early diastolic filling due to ventricular relaxation; shortly after closure of the aortic valve (corresponds to Y descent in JVP).
It may be normal in children and young /middle aged adults.
Causes of an abnormal third heart sound are:
Left ventricular failure
Severe MR and TR
VSD, PDA
Constrictive pericarditis
Hypertrophic cardiomyopathy
Dilated cardiomyopathy
AV fistula
thyrotoxicosis
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