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10
Pericardial and Myocardial Disease
Jennifer L. Strande
PERICARDIAL DISEASE
The pericardium is a thin, fibrous sac that envelops the heart and
consists of two layers: visceral and parietal. The space between these
two layers contains a small amount of fluid (15 to 50 mL), which is a
plasma ultrafiltrate. The pericardium has mechanical, immunologic,
and anatomic barrier functions.
Due to a paucity of randomized trial data and absence of practice
guideline statements, the recommendations for assessment and treatment of pericardial disorders in this chapter are largely based on expert
opinion and professional consensus.
Acute Pericarditis
Definition and Epidemiology
Acute pericarditis or inflammation of the pericardium has several
causes. The exact incidence of acute pericarditis is unknown because a
subclinical course is common.
Pathology
About 85% of cases are from idiopathic or viral causes. Less commonly, infection (other than viral), uremia, trauma, metabolic disorders, autoimmune disorders, and neoplastic involvement can also
cause pericarditis. Causes of acute pericarditis are listed in Table 10.1.
Clinical Presentation
The classic manifestation of acute pericarditis is severe and sharp chest
pain, which is often aggravated by a supine position, inspiration, and
cough and relieved by sitting up and leaning forward. The pain is usually substernal and left precordial, and may radiate to the neck, shoulder, and scapular ridge, mimicking that of myocardial ischemia. Chest
discomfort may be mild or absent in patients with connective tissue
disorders, uremia, or neoplastic involvement. Patients may also have
symptoms of low-grade fever, malaise, dyspnea, and less frequently,
hiccups (i.e., phrenic nerve irritation).
In the absence of significant pericardial effusion, results of the
inspection and palpation of the precordium are normal. A highpitched, rasping pericardial friction rub is heard on cardiac auscultation in most patients with acute pericarditis. It may have three
components corresponding to atrial contraction, ventricular systole,
and early diastole, and it is best appreciated at end expiration with the
patient leaning forward. It can be intermittent, and serial auscultation
is recommended.
Diagnosis
The electrocardiographic (ECG) changes of acute pericarditis typically
evolve over days to weeks. The early stage findings are characterized
by diffuse ST segment elevation (i.e., concave upward) with upright
T waves and PR depression. PR depression occasionally precedes the
ST segment elevation. Resolution of the ST elevations is followed by
diffuse T wave inversion. These ECG changes are not always seen and
serial tracings should be obtained.
The laboratory findings of acute idiopathic pericarditis are not specific and consist of mild elevation of the white blood cell count, sedimentation rate, and C-reactive protein level. If indicated, specific testing
for tuberculosis, human immunodeficiency virus (HIV), thyroid disease, or autoimmune disorders is recommended. However, routine performance of viral serologic testing has limited utility. Elevation of serum
cardiac biomarkers (e.g., creatine kinase, troponin) reflects involvement
of the adjacent myocardium. In uncomplicated acute pericarditis, the
chest radiograph and echocardiographic findings are normal. Although
not essential for the diagnosis of pericarditis, echocardiography is the
diagnostic imaging modality of choice for the detection and determination of the hemodynamic significance of a pericardial effusion.
Treatment
Patients with uncomplicated idiopathic or viral pericarditis can be
managed as outpatients. For patients with fever, large pericardial
effusions, or elevated levels of cardiac biomarkers and for those with
possible secondary causes or immunocompromised status, hospitalization for further investigation and treatment should be considered.
Treatment consisting of high-dose nonsteroidal anti-inflammatory
drugs (NSAIDs) is usually effective. Colchicine with NSAIDs or as
monotherapy provides prompt resolution of symptoms and decreases
the recurrence rate. The use of glucocorticoids results in rapid symptomatic improvement. However, glucocorticoids are associated with
higher rates of symptomatic recurrence.
Prognosis
Most patients with idiopathic or viral pericarditis have an uneventful clinical course with complete recovery. Possible complications
include recurrent pericarditis, cardiac tamponade, and constrictive
pericarditis.
Pericardial Effusion and Cardiac Tamponade
Definition and Epidemiology
Pericardial effusion, an abnormal collection of fluid in the pericardial
space, is a relatively common and incidental echocardiographic finding
that is encountered in approximately 10% of studies. Cardiac tamponade occurs when fluid accumulation results in increased intrapericardial pressure, leading to cardiac compression, impaired ventricular
filling, and reduced cardiac output. Accumulation of pericardial fluid
can be caused by virtually any type of acute pericarditis. Pericardial
effusions due to bacterial pericarditis (including tuberculosis), neoplastic involvement, uremic pericarditis, and trauma have a high incidence of progression to tamponade.
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124 SECTION II Cardiovascular Disease
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TABLE 10.1 Causes of Pericarditis
Idiopathic
Infectious
Viral (echovirus, coxsackievirus, adenovirus, cytomegalovirus, hepatitis B
virus, Epstein-Barr virus, human immunodeficiency virus)
Bacterial (Staphylococcus, Streptococcus, and Mycoplasma
species; Borrelia burgdorferi, Haemophilus influenzae, Neisseria
meningitidis)
Mycobacterial (Mycobacterium tuberculosis, Mycobacterium avium-
intracellulare)
Fungal (Histoplasma and Coccidioides species)
Protozoal
Immune or inflammatory
Connective tissue disease (systemic lupus erythematosus, rheumatoid
arthritis, scleroderma)
Arteritis (polyarteritis nodosa, temporal arteritis)
Late after myocardial infarction (Dressler syndrome), late postcardiotomy or
thoracotomy
Drug induced
Procainamide, hydralazine, isoniazid, cyclosporine
Trauma or damage to adjacent structures
Penetrating trauma
Acute myocardial infarction, cardiac surgery, coronary angioplasty,
implantable defibrillators, pacemakers
Pneumonia
Neoplastic disease
Primary: mesothelioma, fibrosarcoma, lipoma
Secondary (metastatic or direct extension): breast, lung, thyroid carcinoma,
lymphoma, leukemia, melanoma
Radiation induced
Miscellaneous
Uremia
Hypothyroidism
Gout
Pathology
The hemodynamic consequences of a pericardial effusion depend on
the rate of accumulation. The normal pericardium has relatively limited
reserve volume. The mechanical properties of the parietal pericardium
are such that when stretched, it becomes rapidly inelastic and resistant
to further expansion. As a result, rapidly accumulating effusions may
result in significant hemodynamic compromise with only 100 to 200
mL of fluid. Conversely, when the accumulation of fluid is slow, the
pericardium undergoes adaptive changes and can accommodate large
(>1500 mL) effusions without the development of tamponade.
Clinical Presentation
The clinical manifestations of a pericardial effusion depend on the size and
rate of fluid accumulation and may range from dyspnea, chest discomfort, and orthopnea to circulatory collapse, pulseless electrical activity, and
death. Compression of adjacent structures such as the phrenic nerve and
the recurrent laryngeal nerve can result in cough or hiccups and hoarseness, respectively. Compression of the esophagus may cause dysphasia.
A normal cardiac examination is not uncommon in patients
with small effusions. With larger effusions, the apical impulse can be
decreased or absent, and the cardiac sound may be muffled. In patients
with acute pericarditis, disappearance of the pericardial friction rub
may indicate development of an effusion. Compression of the left lung
base can result in dullness to percussion, egophony, and bronchial
breath sounds under the left scapula (i.e., Ewart sign).
Patients with tamponade usually appear to be in distress with
tachypnea and tachycardia. The classic physical findings include
hypotension, jugular venous distention with an absent y descent, and
muffled or absent heart sounds. Pulsus paradoxus, a characteristic
physical finding, is defined as a greater than 10 mm Hg of inspiratory
decline of the systolic blood pressure. This results from the inspiratory
decrease of the left ventricular stroke volume and systemic blood pressure. Under normal conditions, the intrathoracic pressure decreases
during inspiration, resulting in enhanced right ventricular filling and
enlargement. In cases of cardiac tamponade, the total heart volume is
fixed, and the right ventricular expansion displaces the interventricular septum toward the left ventricle, with consequent reduction of
the left ventricular stroke volume and systemic hypotension. Pulsus
paradoxus is not pathognomonic of cardiac tamponade and can be
detected in severe chronic obstructive airway disease, pulmonary
embolism, bronchial asthma, constrictive pericarditis, and hypovolemic shock.
Diagnosis
The ECG findings of moderate to large pericardial effusions include
low-voltage QRS complexes and occasionally electrical (QRS) alternans caused by the heart’s swinging motion within the fluid-filled
pericardium. The chest radiograph demonstrates an enlarged cardiac
silhouette. Transthoracic echocardiography, the imaging modality of
choice, provides information regarding the size, location (circumferential vs. loculated), and most importantly, the hemodynamic consequences of the pericardial effusion suggesting tamponade.
The two-dimensional findings of tamponade include right atrial
and right ventricular collapse, distention of the inferior vena cava,
and evidence of increased ventricular interdependence (Fig. 10.1).
Doppler quantification of the mitral and tricuspid inflow velocity
respiratory variation is more sensitive than two-dimensional echocardiography for determining the hemodynamic significance of pericardial effusions. Right heart catheterization demonstrates decreased
cardiac output, elevated right atrial pressure with diminished or
absent y descent, and equalization of the cardiac filling pressures
(i.e., right atrial, pulmonary wedge, and diastolic pulmonary artery
pressures).
Computed tomography (CT) and magnetic resonance imaging
(MRI) can accurately identify pericardial effusions and may be used
along with echocardiography to assess for loculated effusions, pericardial thickening, and extracardiac structures. A diagnostic pericardiocentesis should be performed for evaluating for bacterial, tuberculous,
or malignant causes.
Treatment
Routine drainage of pericardial effusions is unnecessary in the absence
of hemodynamic compromise. Cardiac tamponade is a life-threatening emergency requiring urgent drainage of the pericardial effusion.
Fluid resuscitation should be initiated to increase preload and filling of
the cardiac chambers. Inotropic and vasopressor support has limited
utility. Surgical drainage is appropriate and therapeutic for loculated,
purulent, and tuberculous effusions and for tissue biopsy.
Fluid should be analyzed for pH, cell count, glucose, protein, cholesterol, triglycerides, and acid-fast bacilli by Gram stain, culture,
cytology, and laboratory tests. For patients with chronic, recurring
effusions, the surgical creation of a pleuropericardial window provides
a long-term solution.
Prognosis
The underlying cause of the pericardial effusion and the availability of
effective treatment determine the prognosis.
CHAPTER 10 Pericardial and Myocardial Disease
40
50
30
20
10
0
125
Systole
PE
RV
LV
PE
Fig. 10.1 Parasternal long axis echocardiographic views of the right ventricle in systole and diastole show
right ventricular diastolic collapse (arrow) in a patient with a large, circumferential pericardial effusion. LV, Left
ventricle; PE, pericardial effusion; RV, right ventricle.
Constrictive Pericarditis
Definition and Epidemiology
Pericardial constriction is caused by pericardial inflammation and is a
condition characterized by a rigid, scarred pericardium that limits diastolic filling of the ventricles, resulting in increased intracardiac pressures. The most common causes are infection, prior cardiac surgery,
trauma, and irradiation. Less common causes include connective tissue
disorders, uremia, and neoplastic involvement of the pericardium. In
developing countries, tuberculous pericarditis is a more common cause
of pericardial constriction. Often a specific cause cannot be determined.
Diastole
PE
RV
LV
PE
Pathology
Constriction is the end result of pericardial inflammation with scarring, fibrosis, calcification, and adhesion of the parietal and visceral
layers of the pericardium. Although pericardial thickening is a usual
pathologic finding, its absence does not exclude constriction.
Clinical Presentation
In the early stages, symptoms consist of dyspnea, fatigue, decreased
exercise tolerance, and lower extremity edema. As the disease progresses, early signs and symptoms may be accompanied by ascites,
anasarca, cachexia, and muscle wasting.
Physical examination reveals jugular venous distention with prominent x and y descents and an increase (or failure to decrease) of central venous pressure with inspiration (i.e., Kussmaul sign). The arterial
blood pressure is usually normal, and pulsus paradoxus is absent in
most patients. Ascites and hepatomegaly can be prominent with
advanced disease. On cardiovascular examination, the apical impulse
may be decreased, and the cardiac sounds muffled. An early diastolic
sound (i.e., pericardial knock) corresponding to the abrupt cessation
of early ventricular diastolic filling is pathognomonic of pericardial
constriction, but it is not always detected.
Diagnosis
The diagnosis of pericardial constriction may be challenging and frequently requires the use of multiple imaging modalities. The electrocardiogram may display low QRS voltage, left atrial enlargement, and
nonspecific T-wave changes. Atrial fibrillation occurs in one third of
cases. The chest radiograph may reveal pleural effusions and pericardial calcification, which are best appreciated in the lateral projection.
Transthoracic echocardiography shows dilation of the inferior vena
cava, abnormal interventricular septal motion, and pericardial thickening. Doppler echocardiography demonstrates abnormal respirophasic
variations of the pulmonary and hepatic venous flow and mitral valve
inflow. CT and MRI can accurately measure pericardial thickness.
RV LV
Fig. 10.2 Pressure recordings from a patient with constrictive pericardi-
tis. Simultaneous right ventricular and left ventricular pressure tracings
show equalization of diastolic pressure and dip-and-plateau morphology.
LV, Left ventricle; RV, right ventricle.
Cardiac catheterization is essential in the diagnosis of pericardial
constriction and differentiation from restrictive cardiomyopathy
(RCM). The right atrial pressure tracing shows prominent x and y
descents with equalization of the end-diastolic atrial and ventricular
pressures. The ventricular pressure tracings show a rapid early diastolic
filling of the ventricles, with abrupt cessation in middle and end diastole due to the finite volume of the rigid pericardium (i.e., dip-andplateau morphology or the square root sign) (Fig. 10.2). Enhanced
ventricular interdependence demonstrated by simultaneous measurement of right and left ventricular pressures during respiration is a
more specific finding of pericardial constriction.
Treatment
Medical therapy with sodium restriction and diuretics is of limited efficacy and is only appropriate in patients who are not surgical candidates
due to comorbidities. Pericardiectomy is the only definitive treatment
for constrictive pericarditis.
Prognosis
Pericardiectomy is associated with substantial operative risk that
depends on the extent of cardiac involvement and existence of comorbid conditions. Successful pericardial resection leads to resolution of
the symptoms of constriction over a period of weeks to months. For
patients who are not surgical candidates, the prognosis is poor.
126 SECTION II Cardiovascular Disease
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Effusive Constrictive Pericarditis
Effusive constrictive pericarditis is characterized by a pericardial effusion and a noncompliant or fibrotic parietal and visceral pericardium.
Although it may result from any type of pericardial inflammation, it
is usually seen after cardiac surgery or radiation injury. It likely represents a transition stage between acute pericarditis with effusion and
pericardial constriction. It shares the clinical and hemodynamic features of both conditions.
Typically, drainage of the effusion does not result in resolution of
symptoms, and the central venous and right atrial pressures remain
elevated. In the early stage of the disease, patients may respond to prolonged treatment with NSAIDs. However, visceral and parietal pericardiectomy is often required. For a deeper discussion of this topic, please
see Chapter 68, “Pericardial Diseases,” in Goldman-Cecil Medicine,
26th Edition.
DISEASES OF THE MYOCARDIUM
Myocarditis
Definition and Epidemiology
Myocarditis is an inflammation of the myocardium caused by a variety
of toxins, medications, and viruses. Viral myocarditis, which accounts
for about 20% of cases of dilated cardiomyopathy (DCM), is commonly caused by the enteroviruses, specifically Coxsackie group B
serotypes and, less commonly, adenoviruses, parvovirus B19, hepatitis
C virus, cytomegalovirus, and HIV.
Other causes include bacterial infections such as diphtheria, brucellosis, clostridial infections, legionnaires disease, and meningococcal,
streptococcal, and Mycoplasma pneumoniae infections. Q fever, Rocky
Mountain spotted fever, spirochetal infections (e.g., leptospirosis, Lyme
disease), fungal infections, and parasitic infections (e.g., Trypanosoma
cruzi [Chagas’ disease]) are also known causes of myocarditis.
Pathology
The pathogenesis of viral myocarditis is thought to begin with direct
viral invasion of the myocardium and subsequent immunologic activation. Normal cellular and antibody-mediated immune responses
lead to viral clearing and myocardial healing. However, a few patients
go on to develop DCM and heart failure due to an abnormal immune
response that furthers myocardial damage. The exact mechanisms are
unknown, but they involve cytokines, autoantibodies, and possibly
other processes associated with persistent, low-level viral replication in
myocytes, leading to myocyte atrophy, myocyte apoptosis, and adverse
remodeling of the ventricles. In nonviral infections, the damage is
attributed to the bacterial toxins or abnormal immune responses, and
in parasitic infections, it is largely immune mediated.
Multiple chemicals and drugs can lead to myocardial inflammation
by direct effect or as part of a hypersensitivity reaction. Some of the
common causes include cocaine, chemotherapeutics (e.g., daunorubicin, doxorubicin), and antibiotics.
Giant cell myocarditis is a rare disorder of uncertain origin, but it
can be rapidly fatal. It is usually associated with ventricular arrhythmias and progressive, severe heart failure. Multinucleated giant cells
seen on myocardial biopsy are pathognomonic.
Clinical Presentation
The clinical manifestations range from asymptomatic ECG abnormalities to cardiogenic shock. Patients report heart failure symptoms,
including exercise intolerance, shortness of breath, fluid retention,
and persistent fatigue. In the setting of viral myocarditis, they often
report a viral prodrome, including fever, myalgia, fatigue, respiratory
symptoms, or gastroenteritis that precedes the heart failure symptoms.
Patients are often tachycardic and hypotensive. They may have an
elevated jugular venous pressure, S3 gallop, crackles, and peripheral
edema. Myocarditis can masquerade as an acute coronary syndrome.
Diagnosis
Testing is performed to determine a possible infectious cause. Rising
viral titers are often seen in cases of viral myocarditis. Serum cardiac
enzymes (e.g., troponin, creatine kinase) are measured when myocarditis is suspected. Sinus tachycardia and nonspecific ST- and T-wave
abnormalities are common ECG findings. When the pericardium is
also involved by the inflammatory process, diffuse ST-segment elevations typical for acute pericarditis are also seen. Ventricular ectopy is
common, and atrioventricular conduction defects are seen in myocarditis associated with Lyme disease.
Echocardiography is recommended in the initial diagnostic evaluation to identify ventricular remodeling, including increasing chamber
size and ventricular systolic dysfunction. Cardiac MRI is a promising
technique to detect myocardial inflammation and injury based on
small, observational clinical studies.
Transvenous endomyocardial biopsy should be performed
only when there is rapid deterioration of the clinical condition.
Histopathologic abnormalities such as infiltrating white cells (i.e.,
macrophages, lymphocytes, and eosinophils), evidence of myocardial
damage, and interstitial fibrosis help to establish acute myocarditis, but
the determination is subject to significant intraobserver and interobserver variability. Often the biopsy does not provide a conclusive diagnosis. The endomyocardial biopsy is helpful in diagnosing giant cell
myocarditis (i.e., multinucleated giant cells are seen) or hypersensitivity myocarditis (i.e., eosinophilic infiltrate is seen). Polymerase chain
reaction testing can detect specific viral genomes in the myocardium.
Treatment
Supportive care is the mainstay of treatment. A few patients with fulminant or acute myocarditis require an intensive level of hemodynamic support and aggressive pharmacologic intervention similar to
that for patients with advanced heart failure.
After initial hemodynamic stabilization, treatment should follow current American College of Cardiology and American Heart
Association (ACC/AHA) recommendations for the management of
left ventricular systolic dysfunction. Treatment includes β-adrener-
gic blockers, angiotensin-converting enzyme inhibitors, aldosterone
receptor blockers, and diuretics.
No evidence-based guided therapy for viral myocarditis has been
established. Clinical trials of various forms of antiviral or immunosuppressive therapy (e.g., prednisone, cyclosporine, azathioprine,
intravenous immunoglobulin, interferon immunoadsorption) have
not resulted in conclusive evidence of benefit. Treatment of nonviral
myocarditis is aimed at eradication of the specific infectious agent. For
Chagas’ disease, treatment with antiprotozoal therapy, if initiated early
in the course of infection, may be beneficial.
Hypersensitivity myocarditis and myocarditis associated with toxins respond to withdrawal of the offending agent. Immunosuppressive
therapy has been effective in giant cell myocarditis.
Prognosis
The diverse clinical presentations and causes of myocarditis have limited the understanding of its natural history. It is thought that one
third of the patients fully recover, one third of the patients have some
sequelae in the form of left ventricular systolic dysfunction but are stable on medical therapy, and one third of patients progress to advanced
heart failure. Patients who progress to chronic DCM have 5-year survival rates of less than 50%.
CHAPTER 10 Pericardial and Myocardial Disease
TABLE 10.2 Cardiomyopathies
Disorder Description and Cause
Dilated cardiomyopathy Dilation and impaired systolic function of the left or both ventricles
Familial (genetic) Known or unknown genetic mutations
Nonfamilial Viral myocarditis, nonviral infective myocarditis, idiopathic (immune) myocarditis
Toxins (drugs, alcohol)
Pregnancy (peripartum cardiomyopathy)
Nutritional (thiamine deficiency [beriberi], vitamin C deficiency [scurvy], selenium deficiency)
Endocrine (diabetes mellitus, hyperthyroidism, hypothyroidism, hyperparathyroidism, pheochromocytoma, acromegaly)
Autoimmune (rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis)
Tachycardia induced
Hypertrophic cardiomyopathy Left and/or right ventricular hypertrophy, often asymmetrical (usually more prominent hypertrophy of the interventric-
ular septum)
Familial (genetic) Mutations of sarcoplasmic proteins (several hundred described)
Metabolic storage diseases of the myocyte
Restrictive cardiomyopathy Restrictive filling of the ventricles; ventricles are usually small, atria are markedly enlarged
Familial (genetic) Mutations of sarcomeric proteins
Familial amyloidosis (transthyretin, apolipoprotein)
Hemochromatosis
Desminopathy, pseudoxanthoma elasticum, glycogen storage diseases
Unknown genetic mutations
Nonfamilial Amyloidosis, sarcoidosis, carcinoid, scleroderma
Endomyocardial fibrosis (hypereosinophilic syndrome, idiopathic, chromosomal defect, drugs)
Radiation, metastatic cancer, anthracycline toxicity
Arrhythmogenic right ventricular Progressive fibrofatty replacement of the right and, to a lesser degree, left ventricular cardiomyopathy
Familial Unknown gene mutation
Mutations of intercalated disk protein, cardiac ryanodine receptor, transforming growth factor-β3
127
Unclassified Cardiomyopathies
Takotsubo (stress-induced) cardiomyopathy Transient dilation and dysfunction of the distal parts of the left ventricle (apical ballooning) in the setting of a stress-
ful situation; usually resolves within weeks
Left ventricular noncompaction Characterized by prominent left ventricular trabeculae and deep intertrabecular recesses; familial in most cases,
caused by arrest in the normal embryogenesis of the heart; apex and periapical regions of the left ventricle most
affected; some patients remain asymptomatic, but others develop left ventricular dilation and systolic dysfunction
Cardiomyopathies associated with muscular
dystrophies and neuromuscular disorders
Ion channelopathies Disorders caused by mutations in genes encoding ionic channel proteins; not considered cardiomyopathies because
Cardiomyopathies
Cardiomyopathies are a heterogeneous group of diseases in which the
major structural abnormality is limited to the myocardium. The four
main cardiomyopathic groups are dilated, hypertrophic, restrictive,
and arrhythmogenic right ventricular cardiomyopathy. Atrophic cardiomyopathy is a newer recognized group. Familial (genetic) and nonfamilial (acquired) forms of the diseases have been described.
Duchenne-Becker muscular dystrophy, Emery-Dreifuss muscular dystrophy, myotonic dystrophy, Friedreich’s ataxia,
neurofibromatosis, tuberous sclerosis
they are not associated with typical structural changes of the heart but rather manifest with electrical dysfunction;
some classifications include these disorders as cardiomyopathies: long QT syndrome, short QT syndrome, Brugada
syndrome, catecholaminergic polymorphic ventricular tachycardia
agents, alcohol, cocaine, and radiation, along with deficiency of nutrients such as thiamine (causes beriberi), vitamin C (causes scurvy), carnitine, selenium, phosphate, and calcium, can cause DCM. Peripartum
cardiomyopathy is a rare cause of DCM that can develop during the last
month of pregnancy and up to 6 months after delivery. The pathogenesis
of this peripartum cardiomyopathy is not completely understood, and it
is a diagnosis of exclusion. Risk factors include older maternal age, being
African American, and having multiple pregnancies. Prolonged periods
Dilated Cardiomyopathy
Definition and epidemiology. Cardiac enlargement and systolic
dysfunction in DCM result from a wide spectrum of genetic,
inflammatory, toxic, and metabolic causes (Table 10.2), although
most cases are idiopathic. Abnormal loading conditions such as
hypertension, valvular disease, or coronary artery disease can lead to
similar structural and functional changes; these conditions are not
considered to be part of the DCM group and are discussed elsewhere.
Most cases are thought to result from acute viral myocarditis, a process
described earlier. Exposures to cardiac toxins such as chemotherapeutic
of supraventricular or ventricular tachycardia can lead to idiopathic DCM
(i.e., tachycardia-induced cardiomyopathy). The structural and functional changes usually reverse after the rapid heart rhythm is controlled.
Familial forms of DCM may be responsible for 20% to 30% of
cases. Specific mutations involve genes that encode proteins of the
sarcomere, cytoskeleton, nuclear membrane, and mitochondria; many
mutations remain unknown. The mode of inheritance is typically autosomal dominant, but it can be an X-linked or mitochondrial pattern.
Pathology. Marked enlargement of all four cardiac chambers is
typical of DCM, although the disease sometimes is limited to the left
128 SECTION II Cardiovascular Disease
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or right chambers. The dilation is out of proportion to the ventricular
thickness. Histology reveals evidence of myocyte degeneration with
irregular hypertrophy and atrophy of myofibers with often extensive
interstitial and perivascular fibrosis.
Clinical presentation. DCM usually manifests with symptoms of
heart failure such as fatigue, weakness, dyspnea, and edema. In some
patients, the presenting episode is related to arrhythmia or an embolic
event. On physical examination, signs of decreased cardiac output
are often found, including cool extremities, narrow pulse pressure,
and tachycardia. The cardiac examination reveals a laterally displaced
apex. An S3 gallop is common, along with murmurs of mitral and
tricuspid regurgitation. Pulmonary edema manifests as auscultatory
crackles over the lung fields, and breath sounds may be diminished
if there are pleural effusions. In some patients, the clinical features of
right ventricular heart failure may predominate, with jugular venous
distention hepatomegaly, ascites, and peripheral edema.
Diagnosis. Standard diagnostic procedures include a chest radio-
graph, an electrocardiogram, serum markers, and echocardiography.
The radiograph shows cardiomegaly, pulmonary venous congestion, and
pleural effusions. The electrocardiogram may reveal enlargement of the
heart chambers along with other nonspecific ST- and T-wave abnormalities. Serum B-type natriuretic peptide (BNP) levels are elevated.
Echocardiography provides a comprehensive evaluation of ventricular size and function and valvular function, and it can show a ventricular thrombus. Similar information can be obtained with MRI.
A complete work-up should rule out ischemic, valvular, and hypertensive heart disease as the cause of myocardial dysfunction, and it
should include evaluation for potentially reversible causes of DCM
(e.g., alcohol, nutritional deficiencies). Myocardial biopsy may be considered if the cause of DCM is in question. In patients with a strong
family history, a referral for genetic testing should be considered.
Treatment. Potential reversible causes of DCM should be addressed
(e.g., alcohol cessation, correction of nutritional deficiencies, removal
of cardiotoxic agents). Treatment should follow current ACC/AHA
recommendations for the management of left ventricular systolic
dysfunction and include β-adrenergic blockers, angiotensin-converting
enzyme inhibitors, aldosterone receptor blockers, and diuretics.
Patients with idiopathic DCM who have persistent, moderate to
severe symptoms of heart failure and a QRS duration longer than 120
milliseconds may benefit from cardiac resynchronization therapy with
a biventricular pacemaker. Survival of patients with a left ventricular
ejection fraction less than 35% despite maximal medical management
is improved with the use of implantable cardioverter-defibrillators
(ICDs). Patients with limiting heart failure symptoms despite use of
the previously described therapies may be considered for heart transplantation or support with a left ventricular assist device.
Prognosis. The prognosis of patients with DCM depends on
the response to medical therapy. Some patients have a significant
improvement in symptoms and cardiac function, but in others, the
disease is progressive and associated with a high mortality rate.
Hypertrophic Cardiomyopathy
Definition and epidemiology. Hypertrophic cardiomyopathy (HCM)
is a disease state characterized by left ventricular hypertrophy with
nondilated ventricular chambers in the absence of an apparent cause for
hypertrophy (e.g., hypertensive disease, aortic stenosis). This is a relatively
common genetic disease (1 case in 500 people in the general population)
with autosomal dominant inheritance, although spontaneous mutations
have been described. More than 1400 mutations identified among at
least eight genes encoding proteins of the cardiac sarcomere have been
described, with mutations of the β-myosin heavy chain being the most
common.
Pathology. The main pathophysiologic abnormalities seen in
HCM are left ventricular outflow obstruction, diastolic dysfunction,
mitral regurgitation, and arrhythmias. Obstruction of left ventricular
outflow occurs in roughly one half of the patients. During systole,
the hypertrophied septum bulges into the left ventricular outflow
tract, creating a gradient between the lower part of the left ventricular
cavity and the left ventricular outflow. This causes high-velocity
turbulent flow through the narrowed path, which results in a suction
force (i.e., Venturi effect) that pulls the anterior leaflet of the mitral
valve into the outflow tract. This worsens the obstruction and causes
mitral regurgitation. Diastolic dysfunction from impaired relaxation
properties of the abnormal myocardium causes marked elevation of
left ventricular filling and pulmonary venous pressures, pulmonary
congestion, and limitation in cardiac output. Patients with HCM are
also predisposed to supraventricular and ventricular arrhythmias.
Clinical presentation. HCM is a heterogeneous cardiac disease
with a diverse course and clinical manifestations. Most patients
probably do not suffer sequelae from this disease during their lifetimes.
When the disease does result in complications, there are three relatively
discrete but not mutually exclusive clinical manifestations: sudden
cardiac death due to unpredictable ventricular tachyarrhythmia, most
commonly in young asymptomatic patients (<35 years of age); heart
failure characterized by exertional dyspnea (with or without chest
pain) that may progress despite preserved systolic function and sinus
rhythm; and atrial fibrillation that associates with various degrees of
heart failure.
Heart failure symptoms result from the dynamic obstruction to
left ventricular outflow and diastolic dysfunction. The most frequent
symptom is dyspnea on exertion, followed by ischemic chest pain due
to the increased oxygen demand by the hypertrophied ventricle and
elevated wall tension that reduces blood flow to the subendocardium.
Abnormalities of the structure of small myocardial arteries in HCM
can contribute to myocardial ischemia. Presyncope or syncope can
result from outflow tract obstruction and an inability to increase cardiac output during exertion or from arrhythmias that can be triggered
by exertion. In some, sudden death caused by ventricular arrhythmia
is the initial manifestation of the disease.
Physical examination findings include pulsus bisferiens, a brisk initial upstroke in pulse followed by a midsystolic dip corresponding to
the development of left ventricular outflow tract obstruction, followed
by another rise in late systole. Cardiac examination may reveal a forceful and sustained apical impulse, an audible S4 gallop, and a harsh crescendo-decrescendo systolic murmur best heard along the left sternal
border with radiation to the base of the heart.
Patients may also have an apical holosystolic murmur of mitral
regurgitation. The intensity of the murmur of HCM varies with changing degrees of obstruction. This can be observed with physiologic or
pharmacologic maneuvers that change preload (i.e., left ventricular
filling) or contractility. The intensity of the murmur increases with
a Valsalva maneuver, with assuming a standing position, and after
administration of nitroglycerin or inotropic drugs. The intensity of the
murmur decreases with squatting, volume loading, and administration
of β-blockers.
Diagnosis. Clinical diagnosis is made most commonly with echo-
cardiography and increasingly with cardiac MRI. The diagnosis is
based on a maximal left ventricular wall thickness of 15 mm or more; a
wall thickness of 13 to 14 mm is considered borderline. The diagnosis
can be made in the setting of other compelling information (e.g., family history of HCM). Genetic testing is available to confirm the diagnosis and to screen family members.
Treatment. The ACC/AHA hypertrophic cardiomyopathy guide-
line recommends tailored therapy based on the individual patient. For
A
B
C
Septal
myectomy
Increased
outflow
Reduced
outflow
Incision line through
hypertrophied
basal septum
Fig. 10.3 (A to C) Schematic diagrams of a septal myectomy. (From
Nishimura RA, Holmes DR Jr: Clinical practice: hypertrophic obstructive
cardiomyopathy, N Engl J Med 350:1320-1327, 2004.)
Mitral
regurgitation
asymptomatic patients, the usefulness of β-blockade and verapamil
may be considered. For patients symptomatic with dyspnea or angina,
β-blockers and verapamil are recommended. If patients remain symptomatic, it is reasonable to add disopyramide to a β-blocker or verapamil.
Nonpharmacologic therapies should be considered in patients with
considerable symptoms despite medical management. Septal reduction
therapy is recommended only for patients with severe drug-refractory
symptoms and left ventricular outflow tract obstruction (Fig. 10.3).
Use of ICD therapy for prevention of sudden death is guided by the
perceived risk for ventricular arrhythmias in individual patients. Some
of the characteristics that have been associated with this risk are prior
cardiac arrest or sustained ventricular tachycardia; great (>30 mm)
ventricular wall thickness; syncope, especially if exertional or recurrent; and a first-degree relative with sudden cardiac death. Certain
genotypes appear to convey an increased risk of sudden cardiac death.
Patients with HCM should be excluded from most competitive sports
and should avoid strenuous exercise.
Prognosis. The clinical course of HCM varies. Sudden cardiac
death is the leading cause of mortality. Heart failure symptoms may
gradually progress and patients who are unresponsive to conventional
therapy may require heart transplantation.
Restrictive Cardiomyopathies
Definition and epidemiology. RCM is an uncommon form
of cardiomyopathy characterized by impaired ventricular filling
of nondilated ventricles. RCM can be genetic or acquired. Causes
include infiltrative disorders (e.g., amyloidosis, sarcoidosis, Gaucher’s
disease, Hurler’s syndrome, fatty infiltration), storage diseases (e.g.,
hemochromatosis, Fabry’s disease, glycogen storage disease), other
disorders (e.g., hypereosinophilic syndrome, carcinoid heart disease),
drugs (e.g., serotonin, methysergide, ergotamine), and cancer
treatment (e.g., irradiation, chemotherapy).
Pathology. In the purest form of the disease, the atria are
disproportionately dilated compared with the normal ventricular size,
and the left ventricle has normal or near-normal systolic function
CHAPTER 10 Pericardial and Myocardial Disease
in the absence of hypertrophy. Histology is normally nondistinctive
and can reveal normal findings or nonspecific degenerative changes,
including myocyte hypertrophy, disarray, and degrees of interstitial
fibrosis.
Clinical presentation. Patients often have symptoms and signs of
pulmonary and systemic congestion. The most common symptoms
include dyspnea, palpitations, fatigue, weakness, and exercise intolerance
due to poor cardiac output. As central venous pressure continues
to increase in advanced cases, there may be hepatosplenomegaly,
ascites, and anasarca. The chest radiograph shows atrial enlargement,
pulmonary venous congestion, and pleural effusions.
Diagnosis. The diagnosis of RCM should be considered for patients
with predominantly right ventricular heart failure without evidence
of cardiomegaly or systolic dysfunction. The correct diagnosis often
is not made until months or years after symptom onset. Constrictive
pericarditis can mimic RCM and establishing the correct diagnosis can
be challenging. Distinctive features of the two disorders are described
in Table 10.3.
Treatment. Treatment of RCM focuses on alleviating the symptoms
of heart failure. Diuretics are used for decongestion, but intravascular
depletion may compromise ventricular filling and lead to reduced
cardiac output and hypotension. Supraventricular tachyarrhythmias
are poorly tolerated. In patients with conduction system disease
such as advanced atrioventricular block, a permanent pacemaker
may be indicated. Specific therapies for underlying disorders include
chemotherapy in amyloidosis, phlebotomy and iron chelation therapy
in hemochromatosis, and steroids in sarcoidosis and endomyocardial
fibrosis.
Prognosis. The course of RCM depends on the pathology, and
treatment is often unsatisfactory. In the adult population, the prognosis
usually is poor, with progressive deterioration and death due to lowoutput heart failure.
Arrhythmogenic Right Ventricular Cardiomyopathy
Definition and epidemiology. Arrhythmogenic right ventricular
cardiomyopathy (ARVC) is an autosomal dominant disease characterized by specific myocardial pathology. The estimated prevalence of
ARVC is about 1 case in 2000 to 5000 people, and it has a male predominance.
Pathology. The myocardium of the right ventricular free wall is
progressively replaced by fibrous and adipose tissue. Right ventricular
function is abnormal, with regional akinesis or dyskinesis or global
right ventricular dilation and dysfunction.
Clinical presentation. The disease typically manifests in young
adults as palpitations, dizziness or syncope, or sudden cardiac death.
Symptoms of right ventricular failure are rare, despite evidence of right
ventricular dysfunction on imaging studies.
Diagnosis. The clinical diagnosis of ARVC is suggested by integra-
tion of the information from the clinical presentation (e.g., arrhythmias), electrocardiogram, family history, and imaging studies. When
available, histologic examination of the right ventricle confirms the
diagnosis. The resting electrocardiogram may be normal, but common
abnormalities include incomplete or complete right bundle branch
block, the so-called epsilon waves that follow the QRS complex, and
inverted T waves in the precordial leads. Right ventricular dilation and
systolic dysfunction can be seen with echocardiography and MRI. The
latter modality can also show myocardial fat.
Treatment. Treatment consists of ICD therapy to prevent sudden
cardiac death, but the indications for implantation are not well
defined. Antiarrhythmics and radiofrequency ablation of ventricular
tachycardia are used in patients with frequent arrhythmias, but they
have not been shown to reduce the risk of sudden cardiac death.
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TABLE 10.3 Differentiation of Restrictive Cardiomyopathy From Constrictive Pericarditis
Type of Evaluation Restrictive Cardiomyopathy Constrictive Pericarditis
Physical examination Kussmaul sign present
Apical impulse may be prominent
Regurgitant murmurs are common
Electrocardiography Low QRS voltage (especially in amyloidosis)
Pseudoinfarction pattern
Bundle branch blocks
AV conduction disturbances
Atrial fibrillation
Chest radiography Calcification of the pericardium may be present
Echocardiography Marked enlargement of the atria
Increased wall thickness (especially in amyloidosis)
Doppler echocardiography Restrictive mitral inflow (dominant E wave with short
deceleration time)
No significant variation (<10%) of transvalvular veloci-
ties with respiration
Reversal of forward flow in hepatic veins during
inspiration
Cardiac catheterization
Prominent atrial x and y descents (w sign)
Dip-and-plateau appearance of ventricular diastolic
pressure
Diastolic pressures increased but not equalized; LV
diastolic pressure higher than RV diastolic pressure
Endomyocardial biopsy May reveal specific cause of restrictive cardiomyop-
athy
Computed tomography, magnetic
resonance imaging
AV, Atrioventricular; LV, left ventricular; RV, right ventricular.
Kussmaul sign may be present
Apical impulse usually not palpable
Pericardial knock may be present
Low QRS voltage
Repolarization abnormalities
Atria usually of normal size
Normal wall thickness
Pericardial thickening may be seen
Restrictive mitral inflow (dominant E wave with short deceleration time)
Increased velocity of RV filling and decreased velocity of LV filling with
inspiration; opposite with expiration; variation in velocity exceeds 15%
Reversal of forward flow in hepatic veins during expiration
Prominent atrial x and y descents (w sign)
Dip-and-plateau appearance of ventricular diastolic pressure
Increase and equalization of diastolic pressures
Discordance of RV and LV peak systolic pressures (with inspiration, RV
systolic pressure increases and LV systolic pressure decreases)
No specific findings on endomyocardial biopsy
Pericardial biopsy may reveal abnormality
Pericardial thickening
Patients with a probable or definite diagnosis of ARVC should be
excluded from competitive sports.
Prognosis. The prognosis for these patients remains uncertain.
Unclassified Cardiomyopathies
Some cardiomyopathies that do not fit the current categories are
described in Table 10.2.
For a deeper discussion of this topic, please see Chapter 54,
“Diseases of the Myocardium and Endocardium,” in Goldman-Cecil
Medicine, 26th Edition.
SUGGESTED READINGS
Elliott P, Andersson B, Arbustini E, et al: Classification of the cardiomyopathies: a
position statement from the European Society of Cardiology Working Group
on Myocardial and Pericardial Diseases, Eur Heart J 29:270–276, 2008.
Gersh BJ, Maron BJ, Bonow RO, et al: 2011 ACCF/AHA guideline for the
diagnosis and treatment of hypertrophic cardiomyopathy: a report of the
American College of Cardiology Foundation/American Heart Association
Task Force on Practice Guidelines. Developed in collaboration with the
American Association for Thoracic Surgery, American Society of Echocardiography, American Society of Nuclear Cardiology, Heart Failure Society
of America, Heart Rhythm Society, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons, J Am Coll
Cardiol 58:e212–e260, 2011.
Kindermann I, Barth C, Mahfoud F, et al: Update on myocarditis, J Am Coll
Cardiol 59:779–792, 2012.
Maron BJ, Ackerman MJ, Nishimura RA, et al: Task Force 4: HCM and other
cardiomyopathies, mitral valve prolapse, myocarditis, and Marfan syndrome, J Am Coll Cardiol 45:1340–1345, 2005.
Maron BJ, Towbin JA, Thiene G, et al: Contemporary definitions and classifi-
cation of the cardiomyopathies: an American Heart Association scientific
statement from the Council on Clinical Cardiology, Heart Failure and
Transplantation Committee; Quality of Care and Outcomes Research and
Functional Genomics and Translational Biology Interdisciplinary Working
Groups; and Council on Epidemiology and Prevention, Circulation
113:1807–1816, 2006.
Yancy CW, Jessup M, Bozkurt B, et al: 2013 ACCF/AHA guideline for the
management of heart failure: a report of the American College of Cardiology Foundation/American Heart Association Task Force on Practice
Guidelines, Circulation 128:1810–1852, 2013.
11
Other Cardiac Topics
Jinnette Dawn Abbott, Sena Kilic
CARDIAC DISEASE IN PREGNANCY
Pregnancy is associated with dramatic changes in the cardiovascular
system that may result in significant hemodynamic stress to the patient
with underlying heart disease. During a normal pregnancy, plasma
volume increases an average of 50%, beginning in the first trimester and peaking between the 20th and 24th weeks of gestation. This
change is accompanied by increases in stroke volume, heart rate, and,
accordingly, cardiac output. In addition, a concomitant fall in systemic
vascular resistance and mean arterial pressure occurs because of the
effects of gestational hormones on the vasculature and the creation of a
low-resistance circulation in the pregnant uterus and placenta. During
labor, uterine contractions result in a transient increase of up to 500
mL of blood in the central circulation, resulting in further increases in
stroke volume and cardiac output. After delivery, intravascular volume
and cardiac output increase further as compression of the inferior vena
cava by the gravid uterus is relieved and extravascular fluid is mobilized. The American Heart Association guidelines for the prevention of
cardiovascular disease in women identified pregnancy complications as
risk factors for cardiovascular disease in women. Hypertensive disorders of pregnancy and gestational diabetes mellitus are independently
associated with increased 10-year cardiovascular risk.
Most women with cardiovascular disease can complete a pregnancy
and delivery with proper follow-up. While cardiac disease may sometimes be manifested for the first time in pregnancy, the symptoms
and signs that may mimic cardiac disease often accompany the usual
hemodynamic changes of pregnancy, including fatigue, reduced exercise tolerance, lower-extremity edema, distention of the neck veins, S3
gallop, and new systolic murmurs. Differentiating symptoms produced
by cardiac disease from those attributable to a normal pregnancy can
be difficult. Under such circumstances, echocardiography can be a safe
and helpful noninvasive test to assess cardiac structure and function in
the pregnant patient.
Certain cardiac conditions, including pulmonary hypertension,
cardiomyopathy, valvular heart disease and connective tissue disorders
including Marfan syndrome with a dilated aortic root, are associated
with a high risk for cardiovascular complications and maternal death
and require special consideration and counseling. The risk for cardiac
complications during pregnancy depends on the maternal conditions
as summarized in Table 11.1.
Specific Cardiac Conditions
Valvular Heart Disease
Due to the declining incidence of rheumatic heart disease in Western
countries, valvular heart disease is infrequent in North America but
remains prevalent in developing countries. Bicuspid aortic stenosis and
mitral stenosis are the most common valvular diseases encountered
during pregnancy. When aortic stenosis complicates pregnancy, it is
usually secondary to a congenital bicuspid aortic valve whereas mitral
stenosis is the most common rheumatic valvular disease encountered
during pregnancy. These valvular conditions tend to worsen during
pregnancy due to the increased cardiac output and tachycardia.
Congestive heart failure may develop as the pregnancy progresses and
may be worsened by the onset of atrial fibrillation. Careful echocardiographic assessment is recommended, and the cornerstone of therapy
for the symptomatic patient is β-blockade. In patients with symptoms
refractory to medical therapy aortic balloon valvuloplasty for aortic
stenosis or mitral balloon valvotomy for mitral stenosis can be considered. Mitral and aortic regurgitation are usually well tolerated in pregnancy provided the regurgitation is no more than moderate in severity,
the woman is symptom-free before pregnancy, and the left ventricular
function is normal.
Prosthetic valves. When selecting a prosthetic valve for women of
childbearing age, careful consideration has to be made with regards to
the type of valve. Mechanical valves have greater longevity but routinely
involve the use of warfarin, which is associated with a higher chance
of fetal loss, placental hemorrhage, and prosthetic valve thrombosis.
Tissue valves are less thrombogenic but tend to degenerate after an
average of 10 years, necessitating a re-operation, which carries certain
operative risks including mortality.
There is no universal consensus on the management of a pregnancy
when the mother has a mechanical valve prosthesis. Prepregnancy counseling should include a detailed discussion of the risks to the patient.
During pregnancy, increased platelet adhesiveness, increased concentration of clotting factors, and decreased fibrinolysis increase the risk
of maternal valve thrombosis and thromboembolism. Unfractionated
heparin, used subcutaneously or intravenously, is begun in the first
trimester, as soon as pregnancy is diagnosed, to minimize fetal exposure to the teratogenic effects of warfarin. It is usually continued until
week 13 or 14 of pregnancy, when fetal embryogenesis is complete,
after which warfarin is resumed. Continuing heparin throughout pregnancy has been shown to increase valve thrombosis risk to 33%. Lowmolecular-weight heparin is an alternative to unfractionated heparin
but its use remains controversial with no large prospective studies or
evidence base to support its use and therapeutic monitoring.
Marfan Syndrome
Pregnant women with Marfan syndrome are at increased risk for
aortic dissection and rupture, especially during the third trimester
and the first postpartum month. Pregnancy is contraindicated in
women with an aortic root diameter greater than 40 mm. Periodic
echocardiographic surveillance every 6 to 8 weeks is recommended
to monitor the mother’s aortic root size and treatment with β-adrenergic blockers is recommended. Vaginal delivery is safe in patients
with Marfan syndrome with an aortic diameter less than 40 mm. To
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TABLE 11.1 Specific Maternal Cardiac Conditions and Risk for Cardiac Complications During
Pregnancy
Low Risk Intermediate Risk High Risk
Small left-to-right shunts Large left-to-right shunt New York Heart Association class III or IV symptoms
Repaired lesions without residual dysfunction
Mitral valve prolapse without regurgitation
Bicuspid aortic valve without stenosis
Mild to moderate pulmonic stenosis
Valvular regurgitation with normal ventricular
systolic function
Unrepaired or palliated cyanotic congenital heart disease
Mechanical prosthetic valves
Mitral or aortic valve stenosis
Severe pulmonic stenosis
Moderate to severe ventricular dysfunction
Unrepaired coarctation of the aorta
History of peripartum cardiomyopathy without residual
ventricular dysfunction
Severe pulmonary hypertension
Marfan syndrome with aortic root dilation or major
valvular disease
Severe aortic stenosis
History of peripartum cardiomyopathy with residual
ventricular dysfunction
minimize pain and hemodynamic changes, epidural anesthesia and
β-blockers or vasodilators should be used and forceps or vacuum
use is recommended to shorten the second stage of labor. In patients
with aortic diameter 40 mm or greater, delivery via elective C-section
should be performed in a tertiary care center with cardiothoracic surgical expertise.
Congenital Heart Disease
Congenital heart disease is the predominant maternal cardiac disease
in Western societies, and all patients with a history of congenital heart
disease, whether or not they have had repair, should receive a detailed
evaluation and appropriate counseling before conception. Patients
with uncomplicated atrial or ventricular septal defects usually tolerate pregnancy without complications unless they have concomitant
pulmonary hypertension or atrial fibrillation. In patients with pulmonary hypertension, pregnancy is contraindicated. The added volume
load of pregnancy may potentially precipitate left ventricular failure in
patients with large intracardiac shunts.
In women with coarctation of the aorta, symptoms may first present during pregnancy, typically as systemic hypertension. Therapeutic
options such as antihypertensive therapy, percutaneous stenting of the
coarctation, and surgical intervention are available and most women
will have a successful pregnancy with proper care.
Women with uncorrected tetralogy of Fallot should undergo palliative or definitive repair before conception to improve maternal and
fetal outcomes. Women with residual obstruction of the right ventricular outflow tract are at risk of worsening cyanosis and risk to both
mother and fetus during pregnancy.
Heart Disease Arising During Pregnancy
Hypertension
Hypertension is the most common medical problem in pregnancy.
It is defined as absolute blood pressure values greater than 140 mm
Hg systolic or 90 mm Hg diastolic. The major forms of hypertension that may develop during pregnancy are essential or primary
hypertension, gestational hypertension, preeclampsia superimposed
on essential hypertension, and preeclampsia. Essential hypertension is defined as hypertension, without a secondary cause, present
before pregnancy or that is diagnosed before week 20 of gestation.
Gestational hypertension is new hypertension without proteinuria
that occurs after the 20th week of gestation and resolves within 2
weeks after delivery.
The mainstay of treatment of hypertension in pregnancy is antihypertensive medications, which are usually effective in treating
essential hypertension but not effective in preventing preeclampsia.
Agents that have been safely used in pregnancy include hydralazine, α-methyldopa, clonidine, β-blockers, and labetalol. Diuretics
should be used with caution because of the increased risk for placental hypoperfusion. When preeclampsia develops, typically characterized by hypertension and proteinuria, bedrest, salt restriction,
and close monitoring are initiated and magnesium sulfate can be
administered to prevent eclamptic seizures and prolong pregnancy
to facilitate fetal maturity. Blood pressure usually normalizes rapidly with delivery.
Peripartum Cardiomyopathy
Peripartum cardiomyopathy (PCM) is a form of dilated cardiomyopathy that may begin during the last trimester of pregnancy or within 5
months of delivery in a previously healthy woman. The true incidence
of the disease is unknown, but estimates conclude that 1 in every 2500
to 4000 pregnancies is affected in the United States. Although the cause
of PCM is unknown, myocardial injury is thought to be immunologically mediated with inflammation playing a key role as evidenced by
elevated serum markers of inflammation in many patients. Known risk
factors include multiparity, black race, older maternal age and preeclampsia. Women usually exhibit symptoms and signs of congestive
heart failure and cardiac imaging, usually with a transthoracic echocardiogram, establishes the diagnosis.
Management is similar to that for congestive heart failure (see
Chapter 5) and usually includes the use of hydralazine, β-blockers,
digoxin, and diuretics for symptom management and preload reduction. Diuretics may potentially reduce placental blood flow and must
be used with caution. Angiotensin-converting enzyme inhibitors have
been associated with increased fetal wastage in pregnant animals and
aldosterone antagonists may have antiandrogenic effects on the fetus;
therefore both classes of drugs should be avoided. Nitrates and inotropes may be necessary in severe cases and early fetal delivery may
be necessary. Mechanical circulatory support may be necessary and
cardiac transplantation may be considered in those cases refractory to
mechanical circulatory support.
The outcome with PCM is variable. Left ventricular function normalizes in approximately 23% to 54% of women and death or progressive heart failure occurs in one third of affected women. The recurrence
rate with subsequent pregnancies is 30%. In patients with full recovery
of left ventricular function, mortality is negligible in subsequent pregnancies; however, women with a left ventricular ejection fraction less
than 25% at diagnosis or persistent left ventricular dysfunction should
be counseled against a subsequent pregnancy.
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