Aortic stenosis is narrowing of the aortic valve orifice.
Normal aortic valve orifice: 2.5-3.5 sq.cm
Critical aortic stenosis: <1 sq. cm
Causes of AS:
Rheumatic fever
Congenital- Bicuspid aortic valve
Calcification of the aortic valve (old age)
Symptoms (3 cardinal symptoms of Aortic stenosis):
1.Exertional dyspnea
2.Syncope (due to reduced cerebral perfusion)
3.Angina pectoris (due to low cardiac output)
Signs
Low blood pressure (because of reduced cardiac output) and Low pulse pressure( in supine position)
Pulse: pulsus parvus et tardus (slow rising pulse), low volume, regular
Apex beat: heaving, normal in position (because the LVH is concentric)
Murmur : midsystolic ejection murmur with direction of selective propagation towards the carotids is heard. The murmur is best audible in the aortic or neoaortic area in full expiration with the patient sitting and leaning forward, and with the diaphragm of stethoscope. (Occasionally, the murmur of AS is transmitted to the mitral area and is known as Gallavardin’s phenomenon).
The murmur of AS is crescendo-decrescendo murmur or saw-like murmur as shown in the diagram.
S2 is muffled/soft.
Ejection click present (it is heard just after S1 because of the sudden opening of aortic and pulmonary valves)
Systolic thrill felt in the aortic area.
Systolic thrill felt in the carotid artery called carotid shudder.
Why is the murmur mid systolic?
Because, during midsystole, the pressure gradient between the left ventricle and aorta is the greatest.
Types of LVH?
Concentric Hypertrophy: Muscle mass increases, no dilatation, the left ventricle cavity size is decreased. Apex is normal in position.
Eccentric hypertrophy: Muscle mass is increased, there is dilatation of the left ventricle, apex is shifted outwards and downwards.
Complications
1.LVF, RVF
2.Angina, syncope
3.Tachyarrhythmia, bradyarrhythmia
4.Infective endocarditis
5.Complete heart block or ventriclular tachycardia ( may cause sudden death)
Investigations
1.Chest X-ray:
Normal sized heart due to concentric LVH.
Post stenotic dilatation of aortic valve.
Aortic valve calcification.
2.Fluoroscopy: calcification of aortic valve maybe seen.
3.ECG: Features of LVH, LAH, LBBB, 1st degree heart block.
4.Echocardiography shows chamber enlargement and calcific aortic valve
5.Blood test to detect active rheumatic carditis: TLC, DLC, ESR, ASO titre
6.Cardiac catheterisation
7.Coronary angiogram
Treatment
- Medical management of LVF, angina, atrial fibrillation
- Young: Valvotomy
- Adults and elders: Valvuloplasty
- Calcific AS: Aortic valve replacement
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