Cardiac Valve defects

Question 1

Cardiac valve defects may be incompetent (regurgitant), stenosed or both. Abnormal valves produce turbulent flow which can be heard as a murmur on auscultation; a few murmurs are also felt as a thrill on palpation.

What is the S₁ heart sound?

Answer 1

• closure of mitral + tricuspid valves at start of isovolumetric contraction
• V_P > A_P -> so AV valves close
• valves open during end of diastole
• soft if long PR or mitral regurgitation

Question 2

What is the S₂ heart sound?

Answer 2

• closure of aortic + pulmonary valves
• Aorta_P + Pulm_p > ventricular_p -> semilunar valves close
• splitting during inspiration is normal

Question 3

What is the S₃ heart sound?

Answer 3

• third heart sound - ‘ventricular gallop’
• ‘kentucky gallop’ - (S₁ - Ken, S₂ - tuck, S₃ - y)
• caused by diastolic filling of ventricle
• considered normal if < 30 yrs old (may persist in woman up to 50y)
• heard in left ventricular failure (eg. dilated cardiomyopathy), constrictive pericarditis (aka pericardial knock) and mitral regurgitation

Question 4

What is the S4 heart sound?

Answer 4

• occurs just before S₁ only if pathology present
• ‘atrial gallop’
• caused by atrial contraction against a stiff ventricle
• may be heard in aortic stenosis, HOCM + hypertension
• in HOCM a double apical impulse may be felt as a result of a palpable S4

S₃ and S₄ may occur together in what is known as a quadruple gallop or may merge to produce a summation gallop S₇

Question 5

What are examples of ejection systolic murmurs?

Answer 5

• aortic stenosis
• pulmonary stenosis, HOCM
• ASD, Fallot’s

Question 6

What are examples of pansystolic/holosystolic murmurs?

Answer 6

• mitral/tricuspid regurgitation (high-pitched + ‘blowing’ in character)
• VSD (‘harsh’ in character)

Question 7

What are examples of late systolic murmurs?

Answer 7

• mitral valve prolapse
• coarctation of aorta

Question 8

What are examples of early diastolic murmurs?

Answer 8

• aortic regurgitation (high pitched + ‘blowing’ in character)
• Graham-Steel murmur (pulmonary regurg, again high pitched + ‘blowing’ in character)

Question 9

What are examples of mid-late diastolic murmurs?

Answer 9

• mitral stenosis (‘rumbling’ in character)
• austin-flint murmur (severe aortic regurgitation, again rumbling in character)

Question 10

What is an example of a continuous machine-like murmur?

Answer 10

patent ductus arteriosus

Question 11

What are the signs and symptoms of aortic stenosis and what is characteristic of this specific murmur?

Answer 11

• ejection systolic murmur - right 2^nd ICS
• crescendo-decrescendo
• radiates to carotids bilaterally
• pitch = medium
• symptoms*: dyspnoea, angina, exertional syncope, systemic emboli, sudden death
• signs: slow rising carotid pulse, narrow pulse pressure, displaced, thrusting apex beat, soft S₂ (absent S2 in severe disease), brachio-radial delay, late + weak pulse

*(SAD = syncope, angina, dyspnoea)

Question 12

What are common causes of aortic stenosis?

Answer 12

• cusp calcification of bicuspid aortic valve - calcification develops approx 30yrs w/ progressive stenosis, thought that years of turbulent flow across abnormal valve disrupt endothelium and collagen matrix of leaflets, resulting in gradual calcium deposition
• age-related calcification of the normal tricuspid aortic valve - normal aortic valve is tricuspid where about 1-2% of pop have a bicuspid valve, it is thought cumulative wear + tear of valve motion over many years leads to endothelial + fibrous damage, causing calcificiation of an otherwise normal valve
• post rheumatic fever valve disease (rare in UK)
• congenital: William’s, Turner’s

Question 13

What is the pathophysiology of aortic stenosis?

Answer 13

• blood flow across aortic valve is impeded during systole
• as a consequence, significantly elevated left ventricular pressure is necessary to drive blood into aorta
• since AS develops over chronic course, the LV is able to compensate by undergoing hypertrophy in response to the higher systolic pressure it must generate to maintain output
• ie. gradual development of LV outflow obstruction causes gradual pressure overload of LV + results in compensatory LV hypertrophy
• however, hypertrophy reduces compliance of ventricle -> resulting elevation of diastolic** pressure -> **LA hypertrophy in order to fill the ‘stiff’ LV

as a consequence of the compensatory changes, there is a long asymptomatic period - eventually, the heart decompensates and there is deterioration in cardiac function leading to development of symptoms.

Question 14

What are relevant investigations for aortic stenosis?

Answer 14

• transthoracic echocardiogram - best for initial + subsequent evaluation of AS, used when there is an unexplaine dsystolic murmur, a single second heart sound, a history of a bicuspid aortic valve or symptoms that might be due to AS -> it shows elevated aortic pressure gradient
• ECG - may show LVH and absent Q waves, AV block, hemiblock or bundle branch block
• cardiac catheterisation - useful for diagnosis only when echo is inconclusive, shows elevated aortic pressure gradient

Question 15

What does left ventricular hypertrophy look like on an ECG?

Answer 15

• Results in increased R wave amplitude in the left-sided ECG leads (I, aVL and V4-6) and increased S wave depth in the right-sided leads (III, aVR, V1-3)
• The most commonly used criteria are the Sokolov-Lyon criteria (S wave depth in V1 + tallest R wave height in V5-V6 > 35 mm)
• ST segment depression and T wave inversion in the left-sided leads: AKA the left ventricular ‘strain’ pattern
• Left axis deviation also common

Question 16

What is the management of aortic stenosis in a clinically stable patient who is asymptomatic?

Answer 16

• severe AS:
  
  • referral for surgical valve replacement if EF <50%
  • when surgery not performed, pts w/ severe AS should have echo every 6-12 months + regular clinical follow-up
• non-severe AS - undergoing no surgery:
  
  • serial transthoracic echos every 3-5 years (mild AS) and 1-2 years (moderate AS)
• non-severe AS - undergoing bypass, valve or aortic surgery:
  
  • concomitant prophylactic valve replacement

Question 17

What is the management of aortic stenosis for clinically stable patients who are symptomatic?

Answer 17

• surgical aortic valve replacement - STS-PROM and EuroScore II are two risk assessment tools helpful for individual patient’s operative risk, valve replacement appropriate therapy for most symptomatic pts w/ severe AS, prosthetic aortic valves used in surgical valve replacement may be mechanical or bioprosthetic
• long-term infective endocarditis antibiotic prophylaxis
• long-term anticoagulation - in those pts who have had aortic valve replacement using prosthetic mechanical valves, not required if bioprosthetic valves used except in presence of AF

Question 18

What are the causes of mitral regurgitation?

Answer 18

• MV prolapse
• congenital cleft leaflets
• MV annulus calcification
• heart failure
• Marfan’s
• HOCM
• MI
• myxoma
• papillary muscle rupture
• overload

Question 19

What are the signs and symptoms of mitral regurgitation and what is characteristic of this specific murmur?

Answer 19

• pansystolic - left 5^th ICS
• continuous character
• radiates to left axilla
• high pitch
• symptoms:
  
  • acute - severe dyspnoea due to pulm oedema,
  • chronic - fatigue + exertional dyspnoea (allowing heart to compensate)
• signs: soft S₁, presence of S₃, displaced thrusting apex beat

Question 20

What is the management of mitral regurgitation?

Answer 20

• AF → control rate if fast + anticoag
• Acute → nitrates / diuretics / positive inotropes
• Severe → SURGERY
  
  • Repair over replacement is strong in degenerative regurgitation

Question 21

What are the signs and symptoms of tricuspid regurgitation and what is characteristic of this specific murmur?

Answer 21

• pansystolic murmur - left 4^th ICS
• continous character
• low pitch
• symptoms: fatigue, symptoms of RVF
• signs: signs of RVF

Question 22

What are the signs and symptoms of pulmonary stenosis and what is characteristic of this specific murmur?

Answer 22

• ejection systolic murmur - left 2^nd ICS
• crescendo-decrescendo
• radiates to left side of neck
• medium pitch
• symptoms: asymp, fatigue, syncope
• signs: cyanosis

Can be caused by Noonan syndrome, rheumatic fever and carcinoid syndrome

Question 23

What are the causes of aortic regurgitation?

Answer 23

• supravalvular aortic root disease
• Marfan’s
• CTD
• atherosclerosis
• dissecting aneurysm
• bicuspid valve
• infective endocarditis

Question 24

What are clinical features of aortic regurgitation?

Answer 24

• High-pitched early diastolic murmur
• collapsing pulse + wide pulse pressure
• heaving apex
• Quincke’s sign → capillary pulsation in nail beds
• De Musset’s sign → head nodding w/ each heart beat
• Corrigan’s sign → carotid pulsation

Usually presents w/ LV failure

Ix → ECG, CXR, ECHO, Cardiac catheterisation

Question 25

What is the **management** for aortic regurgitation?

Answer 25

* Main goal is to reduce systolic HTN → **ACE inhibitors** * **Echo** every 6-12 months **Indications for surgery:** * severe AR w/ enalarged ascending aorta * Increasing symptoms * Enlarging LV or deteriorating LV function on ECHO

Question 26

What is the biggest cause of **mitral stenosis**?

Answer 26

Rheumatic fever

Question 27

What is the **clinical** **presentation** of **mitral** **stenosis**?

Answer 27

* **Pulmonary HTN** related * Dyspnoea, haemoptysis, chronic bronchitis-like picture * Hoarseness + dysphagia * Malar flush, low-vol pulse * **AF** common (due to enlarged LA) Ix → **ECG** (p-mitrale), **CXR**, **ECHO**

Question 28

What is the **management** of **mitral** **stenosis**?

Answer 28

* If in AF → **rate control** crucial * Anticoagulate w/ **warfarin** * **Diuretics** reduce preload and pulmonary venous congestion * If above fails to control symptoms → balloon valvuloplasty, open mitral valvotomy, or valve replacement