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Acute aortic regurgitation- Etiology,Features,difference of Acute and Chronic AR

Acute aortic regurgitation occur rapidly. Clinical features are different from chronic aortic regurgitation.
          In this session we will learn about
1.    Etiology of acute AR
2.    Clinical signs of acute AR
3.    Difference between acute AR and chronic AR
Acute AR etiology
1.    Dissection of aorta
2.    Infective endocarditis
3.    Trauma
Features of acute AR
1.    Pulse rate à Tachycardia
2.    Increased chance for hypotension
3.    There won’t be cardiomegaly
4.    Increased chance for pulmonary artery hypotension
-          Left parasternal heave
-          Loud P2 will be present
Following  changes are noted in heart sound
- S1 is soft
- S2 is single and P2 is loud.
- LVS3, S4 are common.
          S1 is soft because of the elevated left ventricular end diastolic pressure closing the valve prematurely.
Murmur in acute AR
          Soft EDM (early diastolic murmur) is heard in acute AR.
It is due to low cardiac output.There is decreased pressure gradient between aorta and left ventricle due to elevated LVEDP.
In acute AR, tachycardia will decrease the duration of diastole  and obscure the murmur of AR.
Austin flint murmur is produced due to premature valve closure due to elevated LVEDP.
Absent peripheral signs in acute AR is due to peripheral vasoconstriction, which attenuate the peripheral signs.
How will you differentiate between acute and chronic AR.

Acute AR
Chronic AR
Pulses parvus
Collapsing pulse
Blood pressure
Normal BP
No cardiomegaly
Cardiomegaly present
Pulmonary hypertension
EDM(Early Diastolic Murmur)
Short EDM
Long EDM
Severity of AR – Assessed with hills sign