heart disease in pregnancy

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  • Cardiovascular disorders in Pregnancy
    • Hemodynamic changes during pregnancy.
      • Blood volume.
        • By 32 weeks’ gestation, total blood volume expands by 40%, with an increase in the total plasma volume up to 50%. (MCQ)
        • Because the red cell mass only increases by 20%, dilutional anemia results. (MCQ)
      • Cardiac output.
        • Increased stroke volume causes cardiac output to increase 30–50% by 20–24 weeks’ gestational age. (MCQ)
        • A marked decrease in cardiac output can occur, however, when a pregnant woman is in the supine position because of caval compression.
      • Systemic vascular resistance
        • decreases during pregnancy (MCQ)
        • It reaches its nadir during the second trimester and then slowly returns to prepregnancy levels by term. (MCQ)
      • Redistribution of blood flow.
        • During pregnancy, blood flow to the kidneys, skin, and uterus increases.
        • Uterine blood flow reaches as high as 500 mL/minute at term. (MCQ)
    • Hemodynamic changes during labor.
      • Venous pressure increases during labor because uterine contractions cause an increase of venous return from the uterine veins.
      • In turn, this results in higher cardiac output, increased right ventricular pressure, and increased mean arterial pressure.
    • Postpartum hemodynamic changes.
      • In the postpartum period, caval compression decreases, which results in an increase of the circulating blood volume. (MCQ)
      • Higher cardiac output ensues, and a reflex bradycardia may occur. (MCQ)
      • Because of increased blood loss, these hemodynamic changes become less pronounced in patients undergoing cesarean section.
  • Cardiac diseases in pregnancy
    • Warning signs.
      • Worsening dyspnea on exertion, or dyspnea at rest
      • Chest pain with exercise or activity
      • Syncope preceded by palpitations or exertion
      • Loud systolic murmurs or diastolic murmurs
      • Cyanosis or clubbing
      • Jugular venous distention
      • Cardiomegaly or a ventricular heave
    • Management of patients with known cardiac disease
      • Sometimes, surgical correction during pregnancy becomes necessary; when possible, procedures should be performed during the early second trimester to avoid the period of fetal organogenesis, but before more significant hemodynamic changes of pregnancy occur. (MCQ)
    • Medical management
      • Prophylaxis for endocarditis.
        • majority of obstetric and gynecologic procedures do not require prophylactic antibiotic treatment for subacute bacterial endocarditis because of the low likelihood of bacteremia (1–5% for a vaginal delivery). (MCQ)
        • For patients at high risk of developing endocarditis prophylaxis is optional, both for vaginal hysterectomies and for vaginal deliveries (MCQ)
        • Antibiotic prophylaxis consists of
          • 2 g of ampicillin IV or intramuscularly plus 1.5 mg/kg of gentamicin IV or intramuscularly before the procedure, followed by one dose of ampicillin 8 hours postpartum.
          • In the event of penicillin allergy, 1 g of vancomycin IV can be substituted.
      • Patients with rheumatic heart disease require either 1.2 million U of penicillin G every month or daily oral penicillin or erythromycin. (MCQ)
      • If anticoagulation is necessary, heparin sodium remains the drug of choice due to the potential teratogenetic effects of warfarin sodium (Coumadin). (MCQ)
  • Valvular heart disease
    • Mitral valve prolapse
      • most common congenital heart defect in young women,
      • it rarely affects maternal or fetal outcome. (MCQ)
    • Mitral stenosis
      • most common rheumatic heart disease in pregnancy
      • increased plasma volume of pregnancy imposes great stress on the cardiovascular system of a woman with mitral stenosis because of the fixed cardiac output(MCQ)
      • Up to 20% of pregnant patients with mitral stenosis become symptomatic by 20 weeks’ gestation, when cardiac output is at its maximum. (MCQ)
      • Management.
        • During pregnancy, affected patients should limit their physical activity.
        • If volume overload is present, they should receive careful diuresis.
        • Arrhythmias, especially atrial fibrillation, should be controlled to avoid decreased diastolic filling time
        • If medical management fails, the patient may require a valve replacement or commissurotomy. (MCQ)
      • Considerations during labor.
        • Cesarean section should be performed for obstetric indications only(MCQ)
        • If significant heart disease exists, especially with pulmonary hypertension, invasive cardiac monitoring with a Swan-Ganz catheter should be considered during labor.
        • The patient should undergo labor in the left lateral position and receive supplemental oxygen.
        • Tachycardia should be prevented because it may lead to decreased cardiac output caused by a decreased diastolic filling time.
        • Verapamil hydrochloride or digoxin may be used to slow the ventricular contraction rate if an atrial arrhythmia is present. (MCQ)
        • Anesthetics may be useful in slowing sinus tachycardia.
        • If an epidural anesthetic is used, care must be taken to prevent hypotension.
        • If necessary, alpha-adrenergic agonists may be used to maintain systemic vascular resistance.
        • The second stage of labor may be shortened by performing a forceps delivery or vacuum extraction delivery. (MCQ)
    • Mitral regurgitation
      • may occur in patients with a history of
        • rheumatic fever
        • endocarditis
        • idiopathic hypertrophic subaortic stenosis
        • most commonly mitral valve prolapse.
      • Typically a decrescendo murmur is detected.
        • This murmur, however, is often diminished during pregnancy(MCQ)
      • In most cases, mitral regurgitation is tolerated well during pregnancy. (MCQ)
      • In severe cases, the onset of symptoms usually occurs later than in cases of mitral stenosis.
      • Atrial enlargement and fibrillation, as well as ventricular enlargement and dysfunction, may develop.
      • Administration of inotropic agents may be necessary if left ventricular dilatation and dysfunction are present.
      • During labor, patients with advanced disease may require central monitoring.
      • The pain of labor may lead to an increase in BP and afterload, which cause pulmonary vascular congestion. Therefore, epidural anesthesia is recommended. (MCQ)
  • Aortic stenosis
      • During pregnancy, mortality for patients may be as high as 17%.
      • Because this disorder is characterized by a fixed afterload, adequate end-diastolic volume, and therefore adequate filling pressure, is necessary to maintain cardiac output.
      • Consequently, great care must be taken to prevent hypotension and tachycardia caused by blood loss, regional anesthesia, (MCQ)
      • Patients should be hydrated adequately
      • placed in the left lateral position to maximize venous return. (MCQ)
      • Affected patients should receive antibiotic prophylaxis. (MCQ)
    • Aortic regurgitation
      • Because of decreased systemic vascular resistance during pregnancy, regurgitation often decreases, and the condition is usually well tolerated.
      • If a patient shows evidence of left heart failure and requires valve replacement, pregnancy should be delayed until after the repair has been completed. (MCQ)
      • If a patient is not yet symptomatic, she should be encouraged to complete her childbearing early, before the onset of symptoms.
      • During labor, afterload reduction by epidural anesthesia is recommended.
      • Bradycardia is poorly tolerated because the increased time of diastole allows more time for regurgitation. (MCQ)
      • A heart rate of 80–100 beats/minute should be maintained.
  • Congenital lesions
    • Left-to-right shunts
      • If the defect has been corrected, the outcome of pregnancy is usually good. (MCQ)
      • If the defect has not been corrected, pregnancy causes only a slight increase in the degree of shunting.
      • If pulmonary hypertension has caused reversal of the shunt, however, the outcome of pregnancy is dismal, with a high rate of maternal mortality.
      • Atrial septal defects
        • most common congenital heart lesions in adults.
        • The defects are usually very well tolerated unless they are associated with pulmonary hypertension.
        • Complications
          • Include atrial arrhythmias, pulmonary hypertension ,heart failure
          • usually do not arise until the fifth decade of life and are therefore uncommon in pregnancy. (MCQ)
        • Ventricular septal defects (VSDs)
          • Because of the increased systemic vascular resistance during labor, epidural anesthesia is recommended. (MCQ)
          • If the patient has pulmonary hypertension or right-to-left shunt, however, this decrease in systemic vascular resistance is poorly tolerated because of decreased perfusion of the lungs.
          • Fetal echocardiography is recommended. (MCQ)
            • The incidence of VSD in the offspring of affected parents is 4%;
    • Patent ductus arteriosus
          • usually tolerated well during pregnancy unless pulmonary hypertension has developed.
          • Because of increased volume, left heart failure and pulmonary hypertension usually worsen during pregnancy. Therefore, pregnancy is not recommended for patients with large patent ductus arteriosus and associated complications. (MCQ)
  • Right-to-left shunts
    • Tetralogy of Fallot
      • If the defect goes uncorrected, the affected patient rarely lives beyond childhood
      • If pregnancy does occur, however, the incidence of heart failure is 40%. shunt can also worsen during the immediate postpartum period because of the decreases in systemic vascular resistance and blood volume. (MCQ)
      • During pregnancy, the fetus should be monitored for intrauterine growth retardation.
    • Coarctation of the aorta.
      • Surgical correction during pregnancy is recommended only if dissection occurs. (MCQ)
      • Coarctation of the aorta is characterized by a fixed cardiac output
      • Therefore, the patient’s heart cannot meet the increased cardiac demands of pregnancy by increasing its beating rate, and extreme care must be taken to prevent hypotension.
      • Two percent of infants of mothers with coarctation of the aorta may themselves exhibit cardiac lesions. (MCQ)
    • Eisenmenger’s syndrome
      • carries a maternal mortality rate of 50% during pregnancy and a fetal mortality rate of more than 50% if cyanosis is present. (MCQ)
      • 30% of fetuses exhibit intrauterine growth retardation
      • termination of the pregnancy is advised
    • Marfan syndrome
      • If a patient’s cardiovascular involvement is minor and her aortic root diameter is smaller than 40 mm, the risks related to pregnancy are similar to those of the general population.
      • If cardiovascular involvement is more extensive or the aortic root is larger than 40 mm, the risks of complications during pregnancy and aortic dissection are significantly increased. (MCQ)
      • Hypertension should be avoided and managed with beta-blockers.
      • Beta-blocker therapy should be considered for patients with Marfan syndrome from the second trimester until delivery, particularly if the aortic root is dilated. (MCQ)
      • Regional anesthesia during labor is considered safe.
    • Idiopathic hypertrophic subaortic stenosis
      • Patients’ conditions improve when left ventricular end-diastolic volume is maximized.
      • Pregnant patients often fare quite well initially because of an increase in circulating blood volume
      • Later in pregnancy, however, decreased systemic vascular resistance and decreased venous return caused by caval compression may worsen the obstruction.
      • This may cause left ventricular failure as well as supraventricular arrhythmias from left atrial distention.
      • management points during labor:
      • Inotropic agents may exacerbate obstruction.
      • The patient should undergo labor in the left lateral decubitus position. (MCQ)
      • Medications that decrease systemic vascular resistance should be avoided or limited
      • Cardiac rhythm should be monitored and tachycardia treated promptly.
      • The second stage of labor should be curtailed by operative delivery.
    • Peripartum cardiomyopathy
      • a dilated cardiomyopathy of unknown cause
      • develops in the third trimester of pregnancy or the first 6 months postpartum. (MCQ)
      • Of the patients who survive, approximately 50% recover normal left heart function, but the others retain permanent cardiomyopathy.
      • Due to the high maternal mortality, subsequent pregnancy is discouraged.
      • Risk factors include (MCQ)
        • multiparity, increased maternal age
        • multiple gestations
        • preeclampsia or eclampsia
      • Management of peripartum cardiomyopathy includes
      • bed rest; sodium restriction;
      • medical therapy with afterload reducers, diuretics
      • inotropics, anticoagulants, or some combination of these
      • in cases of advanced disease, transplantation.
      • Invasive cardiac monitoring should be considered during labor until at least 24 hours postpartum.
      • Hydralazine hydrochloride, furosemide, or digoxin, or some combination of these, may be administered
      • dopamine or dobutamine hydrochloride are given  if necessary.
      • Cesarean section is reserved for obstetric indications.


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