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Valvular Heart Disease
The four valves (tricuspid, pulmonary, mitral,
and aortic) of the human heart work in concert
to ensure unidirectional flow of blood through
the chambers of the heart and the pulmonary
and systemic circuits. The valves themselves
are avascular, thin fibrous structures that open
and close completely and passively with
changes in pressure during the cardiac cycle.
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The tricuspid and mitral valves, which sit between the atria and the
ventricles, open when ventricular pressure is lower than atrial pressure
during diastole and allow ventricular filling. These close immediately with
the onset of ventricular systole as ventricular pressure exceeds that in the
atria; and the pulmonary and aortic valves, which regulate the outflow of
the right and left ventricles, open once ventricular pressure exceeds arterial
pressure.
Following the ejection of blood from the ventricle, chamber pressure falls
again, causing the pulmonary and aortic valves to close. This cycle repeats
with every heartbeat.
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Common causes of heart valve disease include :
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congenital defects,
connective tissue disorders,
infective endocarditis,
rheumatic heart disease, and
calcific disease of aging
Disease or damage to the valve(s) can cause stenosis—obstruction of forward
flow, or regurgitation—inadequate closure, resulting in backward flow of blood.
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Abnormal flow across the diseased valve can often be heard as a murmur:
• mild—generally not clinically significant,
• moderate—may cause symptoms, especially in active individuals, or
• severe—typically associated with symptoms.
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Symptoms of heart valve disease may include:
• fatigue;
• decreased exercise capacity;
• dyspnea (especially with exertion);
• palpitations, angina pectoris, or both;
• Pre-syncope, syncope;
• heart failure with nonproductive cough; and
• lower-extremity swelling (advanced cases
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Mitral Valve Disease
A variety of mitral valve disorders can cause incomplete closure during systole,
which allows blood to flow back (regurgitate) into the left atrium. Symptoms from
the ensuing pulmonary congestion include exertional dyspnea or, in advancing
cases, dyspnea at rest. Eventually pulmonary hypertension with left heart dilation
and failure develops.
Mitral stenosis refers to any narrowing of the mitral orifice. The increased
resistance to ventricular filling causes an inability to augment cardiac output
during exertion. In advanced cases, high left atrial pressure mimics the signs and
symptoms of left ventricular failure, with dyspnea, pulmonary hypertension,
marked fatigue, and lower-extremity edema.
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Mitral Valve Disease
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Rheumatic heart disease is the most common cause (60% of cases).
Streptococcal infection (i.e., strep throat) can cause an inflammatory reaction
in the heart, including the mitral valve, and result in thickening of the valve and
mitral stenosis after 10 years or more. Rheumatic heart disease is commonly
associated with atrial fibrillation and has a high risk of thromboembolism from
atrial fibrillation
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Aortic Valve Disease
Aortic regurgitation results when the aortic valve cusps fail to close securely
during diastole, allowing blood in the aorta to flow back into the left ventricle.
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Aortic stenosis is failure of the aortic valve cusps to freely open during systole,
leading to high left ventricular pressures and limited cardiac output. High
ventricular pressures are necessary to maintain arterial blood pressures
downstream of the narrowing, and these high pressures cause left ventricular
hypertrophy.
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Right-Sided Valvular Heart Disease
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Valvular conditions on the right side of the heart, involving the tricuspid and
pulmonic valves, have multiple origins but cause fewer clinical problems than
aortic and mitral valve disease
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Tricuspid regurgitation is often a functional lesion caused by either
pulmonary hypertension or dilation of the right ventricle, and in these
situations it is rarely severe. Edema and fatigue are potential symptoms,
although tricuspid regurgitation is often asymptomatic.
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Tricuspid stenosis is a rare condition involving obstruction to flow from
the right atrium to the right ventricle. It is almost always due to rheumatic
heart disease and seen in association with mitral stenosis. Lowerextremity edema and ascites are common manifestations of the high
sustained right atrial pressure.
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Right-Sided Valvular Heart Disease
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Pulmonic regurgitation is also rare and can be due to pulmonary hypertension.
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Pulmonic stenosis is a narrowing of the pulmonary valve causing fixed
blood flow to the lungs and increased pressures in the right ventricle.
Management and Medications
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Treatment decisions for valvular heart disease are primarily based on
symptoms. Valvular heart disease is essentially a mechanical disorder, and
definitive treatment requires surgery.
In aortic regurgitation, echocardiography can quantify the regurgitation,
but transesophageal echocardiography and sometimes computed
tomography or magnetic resonance angiography may be needed to
visualize the entire aortic root.
Surgical repair of the native valve is possible in some instances, depending
on the specific anatomic defect. Mitral valve prolapse and bicuspid aortic
valve disease can be repaired (bioprosthetic or metallic valves)
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Valvular Heart Disease
Effects on the Exercise Response
Valvular heart disease affects the exercise response in proportion to the
severity of the lesion.
Severe Mitral Regurgitation
• Hemodynamic response is altered.
• Exercise capacity and peak O2 are reduced.
• High static loads (weightlifting, downhill skiing) may provoke symptoms by
markedly increasing afterload and the regurgitated fraction of cardiac
output
Severe Mitral Stenosis
• Cardiac output may be blunted or fixed.
• Flow limitation may cause exercise-induced hypotension.
• Exertional tachycardia can increase left atrial and pulmonary
pressures, so high heart rate activities (cycling, running,
swimming) are contraindicated.
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Effects on the Exercise Response
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Aortic Regurgitation
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• High static loads (weightlifting, downhill skiing) may provoke symptoms
by markedly increasing afterload and the regurgitated fraction of cardiac
output.
• If left ventricle function is normal, high dynamic loads are often well
tolerated
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Aortic Stenosis
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• Prevents augmentation of cardiac output.
• Flow limitation increases risk of exertional hypotension and syncope
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Effects on the Exercise Response
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Valvular heart diseases commonly cause early exertional fatigue, exertional
dyspnea and a hypotensive pressor response to exercise, and symptoms of
pre-syncope or syncope. Medical and surgical management improves these
exertional symptoms to improve quality of life and preserve independent
functioning.
Exercise management must consider how to perform exercise without
provoking symptoms and whether the specific valvular condition will
worsen with a particular form of exercise.
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Effects of Exercise Training
There are no randomized studies of exercise training with regard to the benefit—or
harm—of exercise for persons with valvular heart disease. Exercise is associated
with a higher quality of life in individuals with valvular heart disease; and in those
who undergo valve surgery, preoperative functional capacity is a strong predictor
of postoperative functional capacity. Symptoms of valvular heart disease may well
restrict activity, but development of such symptoms is usually a strong argument
for surgery, not for reducing activity.
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Recommendations for Exercise Testing
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• Exercise tolerance testing with close attention to the electrocardiographic
and blood pressure response, and is valuable for both symptom diagnosis and
risk assessment before unsupervised exercise.
• Need to assess symptoms such as dyspnea, chest discomfort, palpitations, or
pre-syncope.
• Exercise echocardiography is particularly advantageous for people with
mitral valve disease:
Mitral Regurgitation : Exercise echo to evaluate for exercise-induced
pulmonary hypertension and define functional capacity
Mitral Stenosis: Exercise echo to evaluate the mitral pressure gradient
and pulmonary pressure
Aortic Regurgitation : Exercise testing to assess exertional symptoms and
the hemodynamic response to exercise, looking for systemic hypotension,
pulmonary congestion, or just reduced peak O2.
Aortic Stenosis : Exercise testing to determine the clinical severity of aortic
stenosis. A drop in blood pressure during exertion is an ominous sign, and
can reveal whether someone is truly asymptomatic or simply
sedentary.
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Recommendations for Exercise Programming
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Exercise recommendations for persons with valvular heart disease should take
into consideration the type and severity of valvular heart disease, the type of
exercise (i.e., dynamic or static or a mix of dynamic and static), and the life
circumstances and desires of the individual.
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Individuals who have moderate valvular stenosis or regurgitation should
consult with a cardiologist before starting an exercise program, because
guidance on the type and intensities of exercise remains a clinical judgment
with an insufficient evidence base to make a general recommendation. On
the following slides are general recommendations for mild or severe valvular
heart conditions and after valvular surgery.
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Recommendations for Exercise Programming
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Mild and Asymptomatic to Minimally Symptomatic, Any Valve:
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Any exercise the person wants to do is permissible.
Regular follow-up with the cardiologist is required.
People should avoid going hard enough to cause symptoms.
If increasing symptoms develop, they should see their cardiologist.
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Moderate to Severe and Symptomatic, Mitral or Aortic Valve:
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• Stenosis—avoid high dynamic exercises
• Aortic stenosis—generally low-intensity activities only
• Regurgitation—avoid high static exercise
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Connective Tissue and Congenital Conditions
• Mitral valve prolapse—avoid contact sports
• Genetic disorders of the aortic root—avoid contact sports and high
arterial pressures
• Dilated aortic root—see chapter 15 on aneurysms
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Recommendations for Exercise Programming
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Status Post-valve Repair or Replacement :
• Cardiac rehabilitation with supervised exercise is strongly advised.
• If high-intensity exercise is the goal, exercise testing up to the proposed
level of exertion should be considered.
The medical home staff can coordinate interval follow-up and assessment, which
is especially important for those individuals with moderate degrees of valvular
heart disease. People should be periodically queried about new or progressive
symptoms such as decreased exercise capacity, palpitations, angina, syncope, and
dyspnea.
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