During a normal pregnancy, the maternal cardiovascular system undergoes many changes that put a physiologic strain on the heart. The normal heart can compensate for the increased workload, so that pregnancy, labor, and birth are generally well tolerated, whereas the diseased heart is challenged hemodynamically. If the cardiovascular changes are not well tolerated, cardiac failure can develop during pregnancy, during labor, or during the postpartum period. In addition, if myocardial disease develops, if valvular disease exists, or if a congenital heart defect is present, cardiac decompensation is anticipated
Approximately 1% of pregnancies are complicated by heart disease, and half of all heart disease cases in pregnancy are congenital heart lesions (Cunningham et al., 2001). Box 1 lists maternal cardiac disease risk groups and their related mortality rates.
The degree of disability experienced by the woman with cardiac disease often is more important in the treatment and prognosis during pregnancy than is the diagnosis of the type of cardiovascular disease. The New York Heart Association's functional classification of organic heart disease, a widely accepted standard, is as follows (New York Heart Association, 1964):
• Class I: asymptomatic at normal levels of activity
• Class II: symptomatic with increased activity
• Class III: symptomatic with ordinary activity
• Class IV: symptomatic at rest
No classification of heart disease can be considered rigid or absolute, but this one offers a basic practical guide for treatment, assuming that frequent prenatal visits, good patient cooperation, and appropriate obstetric care occur. Medical therapy is conducted as a team approach, including the cardiologist, obstetric physician, and nurses. The functional classification may change for the pregnant woman because of the hemodynamic changes that occur in the cardiovascular system, especially increased cardiac output. The functional classification of the disease is determined at 3 months and again at 7 or 8 months of gestation.
The incidence of miscarriage is increased, and preterm labor and birth are more prevalent in the pregnant woman with cardiac problems. In addition, IUGR is common, probably because of low oxygen pressure in the pregnant woman. The risk of congenital heart lesions is increased in children of mothers with congenital heart disease (Mendelson, 1997). A maternal mortality rate of more than 50% during pregnancy has been associated with pulmonary hypertension (Mendelson, 1997).
Peripartum cardiomyopathy is congestive heart failure with cardiomyopathy found in the last month of pregnancy or in the first 5 months postpartum (Easterling & Otto, 2002). The etiology of the disease is unknown; theories suggest genetic predisposition, autoimmunity, and viral infections.
Peripartum cardiomyopathy is more likely to occur in African-Americans, in a woman who is 30 years old or more with a twin pregnancy, and in the presence of preeclampsia (Mendelson & Lang, 1995). Maternal mortality rate has been estimated at 25% to 50% (Easterling & Otto, 2002). Clinical findings are those of congestive heart failure (left ventricular failure). Signs include breathless-ness, tachyarrhythmias, and edema with radiologic findings of cardiomegaly. Medical management of cardiomyopathy during pregnancy includes diuretics, potassium, anticoagulants, and digitalis. Intrapartum management includes hemodynamic monitoring; epidural analgesia is appropriate for pain control. The prognosis is good if cardiomegaly does not persist for 6 months postpartum (Easterling & Otto, 2002).
RHEUMATIC HEART DISEASE
Rheumatic fever usually develops suddenly several symptom-free weeks after an inadequately treated group A beta-hemolytic streptococcal infection of the throat. Episodes of rheumatic fever create an autoimmune reaction in the heart tissue, leading to permanent damage of heart valves (usually the mitral valve) and the chordae tendineae cordis. This damage is referred to as rheumatic heart disease (RHD). RHD may be evident during acute rheumatic fever or discovered years later. Recurrences of rheumatic fever are common, each with the potential to increase the severity of heart damage. If a woman has had rheumatic fever in the past, a recurrence can occur during pregnancy, most likely early in the pregnancy. The American Heart Association recommends lifelong prophylaxis with benzathine penicillin, even during pregnancy. For those with penicillin allergies, erythromycin is an acceptable alternative during pregnancy. Heart murmurs resulting from stenosis, valvular insufficiency, or thickening of the walls of the heart characterize RHD. Abnormal pulse rate and rhythm and congestive heart failure are common.
MITRAL VALVE STENOSIS
Mitral valve stenosis (narrowing of the opening of the mitral valve caused by stiffening of valve leaflets, which obstructs blood flow from the atrium to the ventricle) accounts for 90% of RHD seen in pregnancy (McAnulty, Metcalfe, & Ueland, 1995). As the mitral valve narrows, dyspnea worsens, occurring first on exertion and eventually at rest. A tight stenosis plus the increase in blood volume and thus cardiac output of normal pregnancy may cause ventricular failure and pulmonary edema; hemoptysis may occur.
The care of the woman with mitral stenosis typically is managed by reducing her activity, restricting dietary sodium, and increasing bed rest. The pregnant woman with mitral stenosis should be followed clinically for symptoms and by echocardiograms to monitor the atrial and ventricular size, as well as heart valve function. Prophylaxis for intrapartum endocarditis and pulmonary infections is provided.
MITRAL VALVE PROLAPSE
Mitral valve prolapse (MVP) is a common, usually benign, condition occurring in nearly 10% of women of reproductive age (Cunningham et al., 2001). The mitral valve leaflets prolapse into the left atrium during ventricular systole, allowing some backflow of blood. Midsystolic click and late systolic murmur are hallmarks of this syndrome. Most cases are asymptomatic. A few women have atypical chest pain (sharp and located in the left side of the chest) that occurs at rest and does not respond to nitrates. They may also have anxiety, palpitations, dyspnea on exertion, and syncope. Patients usually are treated with beta-blockers such as propranolol (Inderal). Pregnancy and its associated hemodynamic changes may change or alleviate the murmur and click of MVP, as well as symptoms. Pregnancy usually is well tolerated unless bacterial endocarditis occurs. As with RHD, antibiotic prophylaxis is given before invasive procedures for at-risk patients and for complicated vaginal births in patients with MVP.
Marfan syndrome is an autosomal dominant disorder characterized by generalized weakness of the connective tissue, resulting in joint deformities, ocular lens dislocation, and weakness of the aortic wall and root (McAnulty, Metcalfe, & Ueland, 1995). Approximately 90% of individuals with this syndrome have MVP and 25% have aortic insufficiency. There is an increased risk of aortic dissection and rupture during pregnancy. Excruciating chest pain is the most common symptom of aortic dissection. Preconception genetic counseling is recommended to make patients aware of the risks of pregnancy (Shabetai, 1999). Mortality rates may be as high as 50% in women who have significant cardiac disease. If the woman still desires to become pregnant, she should have baseline data gathered about the aortic root. Management during pregnancy is similar to women with class III and IV heart disease.
Infective endocarditis (inflammation of the innermost lining-endocardium-of the heart caused by invasion of microorganisms) is an uncommon disorder during pregnancy (Mendelson & Lang, 1995). It may be seen in women taking street drugs intravenously. Bacterial endocarditis, leading to incompetence of heart valves and thus congestive heart failure and cerebral emboli, can result in death. Treatment is with antibiotics.
Eisenmenger syndrome is a right-to-left or bidirectional shunting that can be at the atrial or ventricular level and is combined with elevated pulmonary vascular resistance (Easterling & Otto, 2002). The syndrome is associated with high mortality rates (30% to 50% in mothers and 50% in fetuses) and thus pregnancy is contraindicated (Kansaria & Salvi, 2000). Contraception is essential, and tubal ligation should be considered because oral contraceptives and intrauterine devices carry considerable risk (Mendelson & Lang, 1995). If pregnancy occurs, termination may be recommended if the woman has significant pulmonary hypertension.
In women who continue pregnancy, physical activity is strictly limited; prophylactic anticoagulation is considered (Mendelson & Lang, 1995). During labor and birth, Swan-Ganz monitoring is essential. Central hypovolemia should be avoided. Oxygen therapy is administered. There is controversy about use of epidural analgesia. If used, serial determinations of arterial oxygen concentrations should be done.
Assessment and Nursing Diagnoses
The presence of cardiac disease makes the decision to become pregnant more difficult. Planned pregnancy requires that the woman understand the peripartum risks. If the pregnancy is unplanned, the nurse needs to explore the woman's desire to continue the pregnancy after examining the risks in relation to the status of her cardiac condition. The woman's partner and family should be included in the discussion.
The pregnant woman with cardiac disease requires detailed assessment to determine the potential for optimal maternal health and a viable fetus throughout the peripartum period. If she chooses to continue the pregnancy, the high risk pregnant woman's condition may be assessed as often as weekly.
The nurse assesses for factors that would increase stress on the heart, such as anemia, infection, and edema, and how the woman is adapting to the physiologic changes of pregnancy. Special attention is given to the review of the cardiovascular and pulmonary systems. The nurse should determine whether the woman has experienced chest pain at rest or on exertion; edema of the face, hands, or feet; hypertension; heart murmurs; palpitations; paroxysmal nocturnal dyspnea; diaphoresis; pallor; or syncope. Pulmonary symptoms such as cough, hemoptysis, shortness of breath, and orthopnea can be signs of cardiac disease. Table 4 lists normal and abnormal cardiovascular signs during pregnancy.
The nurse documents all medication taken by the woman—including over-the-counter (OTC) medications such as supplemental iron—and is alert to their potential side effects and interactions. The woman is also assessed for undue emotional stress that might further compromise her cardiac status. Examples are depression, anxiety/fear of morbidity or mortality for herself and her fetus, financial concerns related to extended hospitalization, anger because of impaired social interaction, and feelings of inadequacy regarding her inability to meet family and household demands.
The woman's cultural background may affect the amount of support that she is able to receive from significant others. Family size (number of children and extended family members in the home), as well as role expectations within the family, may be dictated by cultural norms. For the woman with cardiac impairment, family expectations may prove to be a cause of major stress if she is unable to bear the expected number of children or if it is unacceptable to receive help with domestic chores.
PREGNANT WOMAN: SUBJECTIVE SYMPTOMS
• Increasing fatigue or difficulty breathing, or both, with her usual activities
• Feeling of smothering
• Frequent cough
• Palpitations; feeling that her heart is "racing"
• Generalized edema: swelling of face, feet, legs, fingers (e.g., rings do not fit anymore)
NURSE: OBJECTIVE SIGNS
• Irregular, weak, rapid pulse (>100 beats/min)
• Progressive, generalized edema
• Crackles at base of lungs after two inspirations and exhalations that do not clear after coughing
• Orthopnea; increasing dyspnea
• Rapid respirations (>25 breaths/min)
• Moist, frequent cough
• Cyanosis of lips and nail beds
Routine assessments continue during the prenatal period, including monitoring the amount and pattern of weight gain, edema, vital signs, and discomforts of pregnancy. Additionally, the woman is observed for signs of cardiac decompensation, that is, progressive generalized edema, crackles at the base of the lungs, or pulse irregularity (see Signs of Potential Complications box). Symptoms of cardiac decompensation may appear abruptly or gradually. Medical intervention must be instituted immediately to maintain optimal cardiac status. Dyspnea, palpitations, syncope, and edema occur commonly in pregnant women and can mask the symptoms of a developing or worsening cardiovascular disorder. A woman's sudden inability to perform activities that she previously was comfortable doing may indicate cardiac decompensation.