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Transcript
Valvular Heart Disease
Types
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Mitral Stenosis
Mitral Regurgitation
Mitral Valve Prolapse
Aortic Stenosis
Aortic regurgitation
Tricuspid valve is affected infrequently
– Tricuspid stenosis – causes Rt HF
– Tricuspid regurgitation –causes venous overload
Tricuspid Valve
Rheumatic Heart Disease
• Inflammatory process that may affect the
myocardium, pericardium and or endocardium
• Usually results in distortion and scarring of the
valves
Rheumatic Heart Disease, cont.
• Subjective symptoms
– Prior history of
rheumatic fever
– General malaise
– Pain – may or may not
be present
• Objective symptoms
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Temperature
Murmurs
Dyspnea
polyarthritis
Rheumatic Heart Disease
• Diagnosis
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H/P
WBC and ESR
C-reactive protein
Cardiac enzymes
EKG
Chest x-ray
Echo
Cardiac cath
Cardiac output
Rheumatic Heart Disease
• Nursing Care
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Vital signs
Rest and quiet environment
Give antibiotics, digitalis, and diuretics
Provide adequate nutrition
Monitor I/O
Explain treatment and home care
Mitral Stenosis
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Usually results from rheumatic carditis
Is a thickening by fibrosis or calcification
Can be caused by tumors, calcium and thrombus
Valve leaflets fuse and become stiff and the cordae tendineae
contract
These narrows the opening and prevents normal blood flow
from the LA to the LV
LA pressure increases, left atrium dilates, PAP increases, and
the RV hypertrophies
Pulmonary congestion and right sided heart failure occurs
Followed by decreased preload and CO decreases
Mitral Stenosis, cont.
• Mild – asymptomatic
• With progression – dyspnea, orthopneas, dry cough,
hemoptysis, and pulmonary edema may appear as
hypertension and congestion progresses
• Right sided heart failure symptoms occur later
• S/S
– Pulse may be normal to A-Fib
– Apical diastolic murmur is heard
Mitral Regurgitation
• Primarily caused by rheumatic heart disease, but may be
caused by papillary muscle rupture form congenital, infective
endocarditis or ischemic heart disease
• Abnormality prevents the valve from closing
• Blood flows back into the right atrium during systole
• During diastole the regurg output flows into the LV with the
normal blood flow and increases the volume into the LV
• Progression is slowly – fatigue, chronic weakness, dyspnea,
anxiety, palpitations
• May have A-fib and changes of LV failure
• May develop right sided failure as well
Mitral Valve Prolapse
• Cause is variable and may be associated with
congenital defects
• More common in women
• Valvular leaflets enlarge and prolapse into the LA
during systole
• Most are asymptomatic
• Some may report chest pain, palpitations or exercise
intolerance
• May have dizziness, syncope and palpitations
associated with dysrhythmias
• May have audible click and murmur
Aortic Stenosis
• Valve becomes stiff and fibrotic, impeding blood flow with LV contraction
• Results in LV hypertrophy, increased O2 demands, and pulmonary
congestion
• Causes – rheumatic fever, congenital, arthrosclerosis
• Atherosclerosis and calcification is primary cause in the elderly
• Complications – right sided heart failure, pulmonary edema, and A-fib
• S/S – Early: dyspnea, angina, syncope
Late: marked fatigue, debilitation, and
peripheral cyanosis, crescendodecrescendo murmur is
heard
Aortic Regurgitation
• Aortic valve leaflets do not close properly during diastole
• The valve ring that attaches to the leaflets may be dilated, loose, or
deformed
• The ventricle dilates to accommodate the ^ blood volume and
hypertrophies
• Causes: infective endocarditis, congenital, hypertension, Marfan’s
• May remain asymptomatic for years
• Develop dyspnea, orthopnea, palpitations, ,and angina
• May have ^ systolic pressure with bounding pulse
• Have a high pitch, blowing, decrescendo diastolic murmur
Assessment for Valve Dysfunction
• Subjective symptoms
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Fatigue
Weakness
General malaise
Dyspnea on exertion
Dizziness
Chest pain or discomfort
Weight gain
Prior history of rheumatic heart disease
Assessment, cont.
• Objective symptoms
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Orthopnea
Dyspnea, rales
Pink-tinged sputum
Murmurs
Palpitations
Cyanosis, capillary refill
Edema
Dysrhythmias
Restlessness
Diagnosis
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History and physical findings
EKG
Chest x-ray
Cardiac cath
Echocardiogram
Medial Treatment
• Nonsurgical management focuses on drug
therapy and rest
• Diuretic, beta blockers, digoxin, O2,
vasodilators, prophylactic antibiotic therapy
• Manage A-fib, if develops, with conversion if
possible, and use of anticoagulation
Interventions
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Assess vitals, heart sounds, adventitious breath sounds
^ HOB
O2 as prescribed
Emotional support
Give medications
I/O
Weight
Check for edema
Explain disease process, provide for home care with O2,
medications
Surgical Management of Valve
Disease
• Mitral Valve
– Commissurotomy
– Mitral Valve Replacement
– Balloon Valvuloplasty
• Aortic Valve Replacement
Mechanical Valve
Mechanical Valve
Porcine Valve
Tissue Valve
Tissue Valve
Cardiac murmurs
• Cardiac murmurs are often the first sign of underlying
valvular disease.
• May be systolic or diastolic, pathological or benign.
• Systolic murmurs may be due to physiological
increases in blood velocity or might indicate as yet
asymptomatic cardiac disease.
• Diastolic murmurs are almost always pathological
and require further evaluation.
• An ECG and CXR, although readily available tests,
provide limited diagnostic information.
Echocardiography
Echocardiography can evaluate valve function by the
following imaging modalities:
• 2-D:
Valve motion and morphology;
LV size and function.
• Doppler:
Blood flow velocity; valve
gradients; haemodynamic data.
• Colour flow:
Valvular regurgitation
Management of cardiac murmurs
• Murmur + cardiac symptoms: refer to cardiologist.
• In asymptomatic patients with cardiac murmurs, an
echo is indicated in the following instances:
-
Murmur + abnormal cardiac signs
Murmur + abnormal ECG or CXR
Diastolic or continuous murmurs
Pansystolic or late systolic murmurs
Aortic stenosis
Aetiology
• Aortic stenosis may be congenital or acquired.
• Congenital malformations may be tricuspid, bicuspid or
unicuspid.
• Acquired causes include the following:
-
Degenerative disease
Rheumatic disease
Calcific e.g. end-stage renal failure, Paget’s disease
Miscellaneous e.g. rheumatoid involvement
Aetiology of aortic stenosis
A: Normal aortic valve
B: Congenital aortic stenosis
C: Rheumatic aortic stenosis
D: Calcific aortic stenosis
E: Degenerative aortic stenosis
Aortic stenosis
Grading and severity
• Aortic valve area must be reduced to 25% of normal before
significant circulatory changes occur.
• Grading of stenosis severity is as follows:
Normal valve area = 3-4cm2
Mild stenosis = 1.5-3cm2
Moderate stenosis = 1.0-1.5cm2
Severe stenosis ≤ 1.0cm2
• When stenosis is severe, the peak gradient across the aortic
valve is usually > 60mmHg.
Pathophysiology of aortic stenosis
Aortic stenosis
LV outflow obstruction
LV systolic pressure
Aortic pressure
LV hypertrophy
LV dysfunction
Myocardial ischaemia
LV failure
Aortic stenosis
Natural history of aortic stenosis without operative treatment:
Aortic stenosis
Physical findings
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Slow rising pulse
Reduced systolic and pulse pressure
Systolic thrill over the aortic area
Ejection systolic, crescendo-decrescendo murmur
Soft or inaudible second heart sound
ECG: LVH, AV node conduction defects
Aortic stenosis
Medical therapy
• Conservative treatment should be offered for mild to
moderate aortic stenosis and to asymptomatic patients
with severe aortic stenosis as follows:
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Advise to report symptoms
Avoid vigorous exercise
Antibiotic prophylaxis for endocarditis
Regular follow-up ± echocardiography
Aortic stenosis
Surgical therapy
• Aortic valve replacement should be offered to the following:
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Symptomatic pts with severe AS
Pts with severe AS undergoing CABG surgery
Pts with moderate AS undergoing CABG surgery
Asymptomatic pts with severe AS and LV dysfunction
• Balloon valvuloplasty can play a temporary role as a bridge to
surgery in haemodynamically unstable patients, or as palliation
for patients with serious comorbid conditions
Aortic stenosis
Aortic valve replacement
• In the absence of LV dysfunction, operative risk is
2-8%.
• Indicators of higher mortality are NYHA class, LV
dysfunction, age, concomitant coronary artery
disease, and aortic regurgitation.
• Valve replacement usually results in reduced LV
volumes, improved LV performance and regression
of LV hypertrophy.
Aortic regurgitation
Aetiology
• Either due to primary disease of the aortic valve or wall of the
aortic root or both.
• Causes of primary aortic valve disease include:
Congenital eg. bicuspid aortic valve
Acquired: rheumatic valve disease, infective
endocarditis, trauma, connective tissue disease.
• Causes of primary aortic root disease include:
Degenerative, cystic medial necrosis (eg. Marfan’s),
aortic dissection, syphilis, connective tissue disease,
hypertension.
Pathophysiology of aortic regurgitation
Aortic regurgitation
LV volume
stroke volume
LV mass
systolic BP
LV dysfunction
diastolic BP
myocardial ischaemia
LV failure
Aortic regurgitation
Clinical history
• In chronic severe AR, the left ventricle gradually
enlarges while the patient remains asymptomatic.
Symptoms usually develop after cardiomegaly and
LV dysfunction have occurred. Dyspnoea is the
principal complaint. Syncope is rare and angina is
less frequent than in aortic stenosis.
• In acute severe AR, LV decompensation occurs
readily with fatigue , severe dyspnoea and
hypotension.
Aortic regurgitation
Physical findings
• Collapsing pulse.
• Wide pulse pressure due to both raised systolic blood
pressure and reduced diastolic blood pressure.
• Displaced, diffuse and hyperdynamic apex beat.
• Early blowing diastolic murmur.
• ECG: Left axis deviation, LV hypertrophy.
• CXR: Cardiomegaly, aortic calcification, aortic root
dilatation.
Aortic regurgitation
Management
• Medical treatment includes:
Diuretics, digoxin, salt restriction
Vasodilators
Endocarditis prophylaxis
• Indications for surgical treatment depend on symptoms,
and LV size and function.
• Without surgery, death usually occurs within 4 years of
developing angina and within 2 years after onset of heart
failure.
Aortic regurgitation
Surgical therapy
• Severe acute AR requires prompt surgical intervention.
• Indications for valve replacement in pure, severe, chronic AR
include:
Symptomatic patients with normal LV function
Symptomatic patients with LV dysfunction or dilatation
Asymptomatic patients with LV dysfunction or dilatation
(EF<50% or end-systolic diameter > 55mm)
• Aortic valve and root replacement are indicated in patients
with disease of the proximal aorta and AR of any severity
when the aortic root diameter is ≥ 50mm.
Aortic valve replacement and prognosis
Relation of preoperative LV function to postoperative survival
Mitral stenosis
Aetiology
• Rheumatic fever is the predominant cause.
• Rarely, mitral stenosis is congenital and observed
almost exclusively in infants and young children.
• Miscellaneous rare causes include carcinoid, SLE,
rheumatoid arthritis and mucopolysaccharidoses.
• Causes of left atrial outflow obstruction that may
simulate mitral stenosis include left atrial myxoma,
ball-valve thrombus, infective endocarditis with large
vegetation and cor triatriatum.
Rheumatic mitral stenosis
• Rheumatic mitral stenosis is due to four forms of fusion:
commissural (30%), cuspal (15%), chordal (10%) or combined
(45%).
• The stenotic mitral valve is typically funnel-shaped; the orifice
is frequently shaped like a fish mouth.
• Symptoms usuually occur in the 3rd or 4th decade, but mild MS
in the aged is becoming more common.
• 25% of patients with rheumatic mitral valve disease have pure
mitral stenosis and two-thirds are female.
• May be associated with an atrial septal defect – Lutembacher’s
syndrome.
Mitral stenosis
Pathophysiology
• Normal mitral valve area = 4-6cm2.
• Usually, a mitral valve area ≤ 2.5cm2 must occur before the
development of symptoms.
• A mitral valve area >1.5cm2 usually does not produce
symptoms at rest.
• The first symptoms in mild mitral stenosis are usually
precipitated by exercise, emotional stress, infection, pregnancy
or fast atrial fibrillation.
• A mitral valve area ≤ 1cm2 equates to severe mitral stenosis.
• Pulmonary hypertension results from backward pressure,
pulmonary arteriolar constriction and organic obliterative
changes in the pulmonary vascular bed.
Mitral stenosis
Natural history
• Long latent period of 20 to 40 years from the
occurrence of rheumatic fever to onset of symptoms.
• Once symptoms develop, there is a further 10 years
before symptoms become disabling.
• Once significant limiting symptoms occur, the 10year survival rate is 5-15%.
• When there is severe pulmonary hypertension, mean
survival falls to < 3 years.
• Mortality from untreated mitral stenosis is due to
progressive heart failure (60-70%), systemic
embolism (20-30%) and pulmonary embolism (10%).
Mitral stenosis
Clinical features
• The main symptom is dyspnoea due to reduced lung
compliance.
• Haemoptysis may also occur.
• Approximately 15% of patients experience angina
due to either coincidental coronary artery disease,
right ventricular hypertension or coronary
embolisation.
• Embolic events may occur and 80% of such patients
are in atrial fibrillation.
Mitral stenosis
Physical findings
• Mitral facies – pinkish-purple patches on the cheeks.
• Tapping apex beat – palpable first heart sound.
• Right ventricular heave, loud P2 indicating
pulmonary hypertension.
• Loud first heart sound.
• Opening snap.
• Rumbling, mid-diastolic murmur with
presystolic accentuation in sinus rhythm.
Mitral stenosis
Echo evaluation
• Assessment of valve morphology: degree of
leaflet thickness, mobility and calcification
and extent of subvalvular fusion.
• Estimation of left atrial size.
• Doppler echo: estimation of mitral valve area,
transvalvular gradient and PA pressure.
Mitral stenosis
Medical treatment
• The asymptomatic patient with mild mitral stenosis should be
managed medically. Medical therapy includes:
- Avoidance of unusual physical stress.
- Salt restriction.
- Diuretics if needed.
- Control of heart rate – β-blocker or digoxin.
- Anticoagulation for AF or prior embolic event.
- Annual follow-up.
- Echocardiography if deterioration in clinical condition.
Mitral stenosis
Management of symptomatic mitral stenosis
• Patients with symptoms should undergo clinical reevaluation with echocardiography.
• NYHA class II symptoms and mild mitral stenosis
may be managed medically.
• NYHA class II symptoms and at least moderate
stenosis (MVA≤1.5cm2 or mean gradient ≥5mmHg)
may be considered for balloon valvuloplasty.
• NYHA class III or IV symptoms and severe mitral
stenosis should be considered for balloon
valvuloplasty or surgery.
Mitral stenosis
Balloon mitral valvuloplasty
• The technique involves passing a balloon flotation catheter
across the interatrial septum after trans-septal puncture and
dilating the balloon within the mitral valve orifice.
• Results of the procedure are highly dependent on the
experience of the operator.
• 80-95% of patients have a successful procedure.
• Complications include severe MR, residual ASD, myocardial
perforation, emboli, MI and death.
• Overall event-free survival is 50% to 65% over 3-7 years.
• The underlying mitral valve morphology is the most important
factor in determining outcome.
• Relative contraindications include the presence of a left atrial
thrombus and significant mitral regurgitation.
Mitral stenosis
Mitral valve replacement
• Mitral valve replacement is indicated in patients with severe
mitral stenosis and contraindications to surgical
commisurotomy or balloon valvuloplasty:
- Restenosis following surgical commisurotomy or balloon
valvuloplasty.
- Significant mitral stenosis and regurgitation.
- Extensive calcification of the subvalvular apparatus.
• Operative mortality ranges from 3-8% in most centres.
• Postponement of surgery until the patient reaches NYHA class
IV symptoms should be avoided.
Mitral regurgitation
Aetiology
Mitral regurgitation may be caused by abnormalities of the valve leaflets,
chordae tendinae, papillary muscles or mitral annulus:
• Valve leaflets
- myxomatous degeneration causing mitral valve prolapse
- shortening, rigidity, deformity and retraction due to rheumatic heart disease
- vegetations due to infective endocarditis
• Chordae tendinae
- congenital, infective endocarditis, trauma, rheumatic fever, myxomatous
• Papillary muscles
- myocardial ischaemia, congenital abnormalities, infiltrative disease
• Mitral annulus
- dilatation eg. ischaemic or dilated cardiomyopathy
- calcification due to degeneration, hypertension, aortic stenosis, diabetes,
chronic renal failure
Mitral regurgitation
Clinical features
• Symptoms usually occur with LV decompensation:
dyspnoea and fatigue.
• Physical findings include:
• - Pulse: sharp upstroke
• - Apex: displaced, hyperdynamic
• - Heart sounds: pansystolic murmur loudest at the
apex, radiating to the axilla and accentuated by
expiration.
Mitral regurgitation
Natural history
• The natural history of chronic MR depends on the
volume of regurgitation, the state of the myocardium
and the underlying cause.
• Preoperative LV end-systolic diameter is a useful
predictor of postoperative survival in chronic MR.
• The preoperative LV end-systolic diameter should be
< 45mm to ensure normal postoperative LV function.
Mitral regurgitation
Medical treatment
• Symptomatic patients may benefit from the following
drug therapy whilst awaiting surgery:
• Vasodilator therapy
• Diuretics
• Digoxin / Beta-blockers in presence of atrial
fibrillation.
• Endocarditis prophylaxis
Mitral regurgitation
Surgical treatment
• Surgery is indicated in the presence of symptoms or
left ventricular end systolic diameter ≥45mm.
• The surgical procedure consists of either mitral valve
repair or replacement.
• Mitral valve repair better preserves LV function and
avoids the need for chronic anticoagulation.
• However, mitral valve repair is technically more
demanding and often not possible to perform in
severely deformed valves.
Mitral regurgitation
Relationship of preoperative ejection fraction
to postoperative survival
Acute mitral regurgitation
Aetiology
Important causes of acute mitral regurgitation include:
•
Infective endocarditis causing disruption
of valve leaflets or chordal rupture.
•
Ischaemic dysfunction or rupture of papillary
muscle.
•
Malfunction of prosthetic valve.
Chronic versus Acute MR
Finding
Chronic MR
Symptoms
Appearance
subtle onset
normal/mildly
dyspnoeic
not striking
displaced
common
harsh pansystolic
Tachycardia
Apex beat
Systolic thrill
Murmur
ECG-LVH
CXR
usually present
severe cardiomegaly
Acute MR
obvious
severely ill
always present
not displaced
absent
soft or absent early
systolic component
absent
normal heart size
Acute mitral regurgitation
Medical therapy
The following therapies may be beneficial in reducing the
severity of MR
- Vasodilator therapy
- Inotropic therapy
- Intra-aortic balloon counterpulsation
Surgical therapy
• Indicated in patients with acute severe MR and heart failure.
• Higher mortality rates than for elective chronic MR, but unless
treated aggressively, the outcome is usually fatal.
Mitral valve prolapse
General features
•
•
•
•
Occurs in 2-6% of the general population
Twice as common in women.
Due to myxomatous proliferation of the mitral valve.
Usually occurs as a primary condition, but may be a secondary
finding in connective tissue diseases e.g. Marfan’s syndrome.
• Vast majority of patients are asymptomatic.
• Symptoms may include palpitations, dizziness, syncope, or chest
discomfort.
• The principal physical finding is the mid-systolic click, followed
by a late systolic murmur in the presence of regurgitation.
Mitral valve prolapse
Echocardiographic criteria
• M-mode criterion:  2mm posterior displacement of one or both
leaflets.
• 2-D echo findings: Systolic displacement of one or both leaflets
within the left atrium in the parasternal long-axis view; leaflet
thickening, redundancy, chordal elongation and annular dilatation.
• The diagnosis of mitral valve prolapse is even more certain
when leaflet thickness is >5mm.
• Echocardiography is useful in the risk stratification of patients
with mitral valve prolapse.
Mitral valve prolapse
Natural history
• In most patients, mitral valve prolapse is associated with a benign
prognosis.
• Complications may occur in patients with a systolic murmur,
thickened leaflets an increased LV or LA size, especially in men
> 45 years old:
• Complications include progressive mitral regurgitation, infective
endocarditis, cerebral emboli, arrhythmias and rarely sudden death.
Mitral valve prolapse
Management
• Asymptomatic patients without MR or arrhythmias have an
excellent prognosis – follow-up every 3-5 years.
• Patients with a typical systolic murmur should receive
endocarditis prophylaxis.
• Patients with a long systolic murmur may show progression of
MR and should be reviewed annually.
• Patients with previous embolic events should be given
antiplatelet / anticoagulant therapy.
• Severe MR requires surgery, often mitral valve repair.
Prosthetic valves
Prosthetic valves may be divided into 2 broad categories:
Mechanical valves
• Very good durability.
• Require long-term anticoagulation.
• May cause mild haemolysis.
Bioprosthetic (tissue) valves
• Porcine variety most commonly used.
• Limited durability.
• Anticoagulation for first 3 months only.
Mechanical valves
Designs and flow patterns of different types of mechanical valves
Prosthetic valves
Mechanical versus tissue valves
• No difference in survival, haemodynamics or in probability of
developing endocarditis, valve thrombosis or systemic embolism.
• Valve-related failure is much more common with tissue valves.
• Anticoagulant-related bleeding occurs with mechanical valves.
• Elderly patients tend to receive tissue valves.
Tricuspid stenosis
• Always rheumatic in origin and when present accompanies
mitral valve involvement.
• The anatomical changes and physiological principles are
similar to those of mitral stenosis.
• The low cardiac output state causes fatigue; abdominal
discomfort may occur due to hepatomegaly and ascites.
• The diastolic murmur of tricuspid stenosis is augmented by
inspiration.
• Medical management includes salt restriction and diuretics.
• Surgical treatment should be carried out in patients with a
valve area <2.0cm2 and a mean pressure gradient >5mmHg.
Tricuspid reurgitation
• Most common cause is annular dilatation due to RV failure of
any cause; may also be caused by intrinsic valve involvement
• Well tolerated in the absence of pulmonary hypertension; in
the presence of pulmonary hypertension, cardiac output
declines and RV failure may worsen.
• Symptoms and signs result from a reduced cardiac output,
ascites, painful congestive hepatomegaly and oedema.
• The pansystolic murmur of TR is usually loudest at the left
sternal edge and augmented by deep inspiration.
• Severe functional TR may be treated by annuloplasty or valve
replacement. Severe TR due to intrinsic tricuspid valve disease
requires valve replacement.
Pulmonary stenosis
• Most commonly due to congenital malformation and
usually an isolated anomaly.
• Survival into adulthood is the rule, infective
endocarditis is a risk and right ventricular failure is
the most common cause of death.
• Rheumatic involvement of the pulmonary valve is
very uncommon and rarely leads to serious deformity.
• Carcinoid plaques may lead to constriction of the
pulmonary valve ring.
Pulmonary regurgitation
• Most common cause is ring dilatation due to pulmonary
hypertension, or dilatation of the pulmonary artery secondary
to a connective tissue disorder.
• May be tolerated for many years unless complicated by
pulmonary hypertension.
• The clinical manifestations of the primary disease tend to
overshadow the pulmonary regurgitation.
• Physical examination reveals a right ventricular heave and a
high-pitched, blowing, early diastolic decrescendo murmur
over the left sternal edge, augmented by deep inspiration.
• Pulmonary regurgitation is seldom severe enough to require
specific treatment. Surgery may be required because of
intractable RV failure.