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
Pulse	Pulses parvus	Collapsing pulse
Blood pressure	Hypotension	Normal BP
Apex	No cardiomegaly	Cardiomegaly present
Pulmonary hypertension	Common	Uncommon
LVS4	Common	Rare
EDM(Early Diastolic Murmur)	Short EDM	Long EDM

Severity of AR – Assessed with hills sign