A site for medical students - Practical,Theory,Osce Notes

Showing posts with label Aortic stenosis. Show all posts
Showing posts with label Aortic stenosis. Show all posts

Normal Second heart sound (Identify the abnormalities of S2)

The most difficult thing in auscultation is to identify the abnormalities of S2.

Physiology of Second heartsound
Two components for 2nd heart sound are- aortic and pulmonary

Aortic component it is the 1st component and loud one heard in all areas.

Pulmonary component - 2nd component and soft, heard only over pulmonary area.

Normal second heart sound
It is a high pitched sound with normal split - 2 components are separately heard during inspiration and as single component during expiration over the pulmonary area.
Distance between the 2 components during inspiration is 0.04 sec, during expiration is 0.02 sec. Human ear can appreciate, when the distance between the 2 components is 0.03 or more. Normal second heart sound is expressed as - normal in intensity and normal split with respiration.

Things to look for in S2:
A2 heard over aortic area and pulmonary area and the apex.
P2 heard over pulmonary area and 2-4 LICS only and not at the apex.
P2 heard over the apex only in pulmonary artery hypertension and in young.
Best site for S2 in COPD - epigastrium.

Aortic stenosis clinical presentation

What are the investigation findings in aortic stenosis?

Important investigations in aortic stenosis are
  • ECG
  • CXR
  • Echo
  • Cardiac catheterisation
ECG findings in AS
  • Left ventricular hypertrophy with or without strain may be present (LVH + strain). But absence  of LVH does not rule out the presence of critical AS. There is no correlation between LVH voltage criteria and severity of AS.AS severity correlate with total QRS voltage.
  • Pseudo infarction pattern can be seen, which is seen as loss of r wave in precordial leads
  • Left atrial overload can occur.
  • AV block or left anterior hemiblock.
  • Ventricular arrhythmia and  complete heard block if calcification of valve extend into conducting system.
Chest X-ray findings in AS
  • Normal sized heart with post stenotic diltation can occur. If there is cardiomegaly look for cardiac failure or aortic regurgitation.
  • Left atrial enlargement (LAE) – indicate co-existing mitral stenosis (MS).
  • Calcification of aortic valve may be seen.
Echocardiographic findings in AS
  • Stenotic valve
  • Left ventricular hypertrophy
  • Pressure gradient assessment

Mention the effect of other valvular disease in aortic stenosis (AS) effect of mitral stenosis (MS) on AS

Mention the effect of miral stenosis (MS) on AS
  1. There is decreased severity of angina and syncope due to AS.
  2. Increased chance of atrial fibrillation
  3. Increased chance of pulmonary artery hypertension.
  4. Mitral stenosis decrease the length and intensity of ejection systolic murmur.
Mention the effect of miral regurgitation (MR) on AS
  1. There is decreased severity of angina and syncope due to AS.
  2. Increased chance of atrial fibrillation
  3. Increased chance of pulmonary artery hypertension.
  4. Mitral stenosis decrease the length and intensity of ejection systolic murmur.
What is the effect of AR (Aortic regurgitation) on AS
  1. Pulse volume may be normal if AR is present with AS
  2. Pulse pressure may be normal.
  3. Apex beat is of normal character.
  4. There is an increase in length and intensity of murmur.
What are the auscultatory findings in correlation with age
  1. Split of S2 is usually normal in young.
  2. S2 is usually single in elderly
  3. Aortic ejection click (AEC) is found only  1/3  of people above 50 years.
  4. Loudness of murmur is not well correlated with the severity in adults.
What is silent AS
  1. AS in cardiac failure murmur reappear after treatment of cardiac failure.

How will you assess the severity of aortic stenosis

Clinical features that help in assessing the severity of aortic stenosis are
1.    Pulse
2.    Split of S2
3.    S4
4.    Length of murmur
5.    Peaking of murmur
6.    Loudness of murmur
7.    Thrill
Severity is based on
1.    Splitting of S2
Mild AS         - A2is followed by P2
Moderate AS - A2 is delayed resulting in single S2
Severe AS    - P2 - A2 reverse splitting of S2
2.    Presence of S4 and absent A2
3.    Presence of S3
4.    Long murmur and late peaking of murmur
5.    According to valve surface area
6.    According to gradient across the valve
Mild AS
Moderate AS
1.    Anacrotic pulse
2.    Thrill
3.    Long murmur
4.    Loud murmur
5.    Late peaking
1.    Anacrotic pulse
2.    Thrill
3.    Long murmur
4.    Late peaking
5.    Loud murmur
6.    Paradoxic split
7.    LVS­4
Severity based on valve area
1.    Normal valve area   : 2.5 – 3.5cm2
2.    Tight (critical AS )   : <0.5cm2 / m2 body surface are -0.8cm.
Severity of AS based on hemodynamic gradient
It is based on gradient across the valve
1.    Mild AS         : 25-50mm Hg
2.    Moderate AS : 50-75mmHg
3.    Severe AS     : >75mm/Hg
Severity of aortic stenosis is assessed with
1.    Low volume slow raising pulse
2.    Systolic decapitation of blood pressure
3.    Paradoxical splitting of S2
4.    Presence of S4

Heart sounds in Aortic stenosis

First heart sound in AS
S1 is normal or decreased intensity.
It is due to partial closure of mitral valve in presystole. Lound S1 is associated with MS.
A2 in AS
          Loud A2 indicate pliable valve cusp in congenital AS.
          Soft A2 – Occur due to rigid calcific valve.
Comment on split in AS
          Split may be normal.
          Paradoxical split or single S2 can occur.
When will you get normal split in AS
          Occur in mild to moderate AS.
          Split is normal even in congenital MS.
What is the significance of paradoxic split in AS
          Paradoxic split indicate severe AS if there no left bundles branch block (LLBB) . LV dysfunction seen in only 25% of elderly with severe AS.
          Paradoxical split is due to prolonged electromechanical systole which produce delay in A2 component.
What is the significance of single S2 in AS
         Seen in 66% of elderly with severe AS. It is due to absent A2 or due to masked P2 by the murmur. 
Significance of S4 inAS
          It indicate severe AS in the absence of coronary artery disease or hypertension. Palpable S4 always indicate severe AS.
Aortic ejection click
1.    AEC indicate valvular AS with mobile valves.
2.    AEC is common in congenital AS, and bicuspid aortic valve.
3.    It is rare in elderly.
4.    It disappear with valve calcification.
5.    AEC does not correlate with severity of AS.
6.    Amplitude correlate with that of A2.
What are the features of AEC
1.    AEC  occur after S1.
2.   It is best heard at the apex/ aortic area.
3.    There is no variation with respiration.
4.    It is a high pitched sound.
What is AEC
          It is a high pitched sound produced due to the snapping open of the stenotic thickened aortic valve.
Significance of aortic ejection click
1.    It indicate that the stenosis is at valvular level.
2.    The severity of AS is mild.

Pulse in aortic stenosis

Aortic stenosis is characterized by slow rising pulse with a delayed sustained peak.
          The pulse is called anacrotic pulse (pulses parvus et tardus) . If there is pulses bisferiens that rules out predominant aortic stenosis.
What is the significance of pulse in AS
          If there is normal pulse in adult <60yrs with a normal left ventricular function that rules out moderate to severe aortic stenosis.
What are the factors that affect pulse in AS
1.    Age.
2.    Hypertension.
3.    Hypovolemia.
4.    Left ventricular function.
5.    Presence of pulmonary artery hypertension (PAH).
6.    Mitral valve disease.
7.    Aortic regurgitation.
What are the factors that exaggerate the low pulse volume in AS
1.    Hypovolemia.
2.    Cardiac failure.
3.    Pulmonary artery hypertension.
4.    Associated severe MS (Mild stenosis).
What are the factors which will apparently normalise the pulse in AS
1.    Hypertension.
2.    Presence of aortic regurgitation.
3.    Elderly age.
4.    Young age.

Differentiate between valvular, supravalvular, subvalvular aortic stenosis

The clinical findings of valvular aortic stenosis are presence of ejection click and sott A2
Clinical signs in subvalvular AS are given below
  1. There is early diastolic murmur of AR.
  2. Heart size is larger.
  3. No ejection click or post stenotic dilatation of aorta.

Supravalvular AS signs are
  1. Systolic BP of right  arm is more than left arm.
  2. Thrill is more obvious than other types of AS and is conducted to carotids.
  3. No ejection click, A2 is normal or accentuated no post stenotic dilation of aorta.

What are the clinical examination findings Aortic Stenosis (AS)

Clinical examination reveal the following signs in AS.
1.    Anacrotic pulse.
2.    Low  pulse pressure.
3.    Normal or raised JVP.
4.    Heaving apex-beat.
5.    Basal systolic thrill.
6.    Left parasternal heave if pulmonary artery hypertension is present.
7.    Loud P2 if PAH+.
8.    Paradoxical splitting of S2.
9.    LVS4.
10. Ejection click at apex.
11. Low pitched rough crescendo – descresendo ejection systolic murmur at the aortic area / apex that is conducted to the carotids.
So the signs are
1.    Anacrotic pulse.
2.    Heaving apex.
3.    Systolic thrill at the 2nd right intercostal space.
4.    Soft A2 with paradoxic split.
5.    Aortic ejection click.
6.    Ejection systolic murmur.
What is the blood pressure in aortic stenosis
Low pulse pressure is seen in AS.
If the systolic BP > 200mmHg - It exclude severe AS.
If the systolic BP >140mm/Hg - There will be coexistent aortic regurgitation or hypertension. 
What is the JVP in AS
          JVP is usually normal in AS.
Prominent a wave may occur due to - Bern Hein effect.
Bernhein effect
          In aortic stenosis there is hypertrophy of interventricular septum which bulge into right ventricle producing prominent a wave in JVP.
What are the palpating finding in AS
1.    Hearing apex.
2.    Palpable S4.
3.    Systolic thrill in 2nd RICS.
Comment on the apex beat in AS
Usually heaving apex is seen in AS. There is no displacement. Displaced apex beat may be there in AS due to coexisting aortic or mitral regurgitation and in let ventricular dysfunction.

Symptoms of aortic stenosis (AS)

Important symptoms of AS are
1.    Exertional angina
2.    Exertional syncope
3.    Exertional dyspnea
What is the mechanism of dyspnoea in AS.
          Dyspnoea in AS is due to left ventricular dysfunction resulting in elevated pulmonary capillary pressure.
What is the mechanism of angina in AS
          Angina occur due to the imbalance between myocardial oxygen supply and demand.
1.    There is increased myocardial oxygen demand due to left ventricular hypertrophy (LVH).
2.    Decreased blood supply is due to an increase in left ventricular end diastolic pressure which decreases the coronary perfusion gradient.
What is the mechanism of syncope in aortic stenosis
          Syncope is due to reduction  in cerebral blood flow.
Mechanisms are
1.    Systemic vasodilation against a fixed cardiac output
2.    Transient atrioventricular arrhythmia
3.    Transient AV block
4.    Vasodepressor response due to baroreceptor malfunction
How will you correlate the development of symptoms with survival in AS
Duration of survival
5 yrs
3 yrs
2 yrs
Cardiac failure
Describe the other presentations of AS
          Other presentations of AS are
-          Cardiac failure (CCF)
-          Infective endocarditis (IEC)
-          Sudden cardiac death - it may be due to complete heart block or atrial tachyarrhythmia
-          Gastrointestinal bleeding
What is the mechanism of CVA in AS
1.    Due to embolism from thrombi in valve
Why gastrointestinal bleeding occur in AS
 Angiodysplasia, particulary in persons with calcific AS. A pure aortic valve disease may remain asymptomatic for 10-15 years.

What are the causes of aortic stenosis

Causes of aortic stenosis vary depending on age of the person.
Causes in young adults
-          Congenital valvular lesion
-          Congenital supravalvular lesion
-          Congenital subvalvular lesion
Middle aged persons
-          Bicuspid aortic valve
-          Rheumatic aortic stenosis
Elderly people causes are
-          Bicuspid aortic valve
-          Rheumatic AS
-          Senile degenerative AS
Other rare causes are
Familial hypercholesterolemia
The common causes of AS are the following
-          Rheumatic AS
-          Congenital bicuspid aortic valve
-          Aortic sclerosis
-          Functional AS

          Supravalvular AS may be associated with Elfin facies, mental retardation and hypercalcemia. Elfin facies include broad forehead, pointed chin, cupid’s bow like upperlip – upturnal nose, hypertension and low set ears.