Cardiac disease in pregnancy and hypertrophic cardiomyopathy

Overview
Patients with pre-existing cardiomyopathies such as dilated cardiomyopathy and hypertrophic cardiomyopathy, often have significant difficulty dealing with the physiologic and hemodynamic changes that occur during pregnancy, labor, and delivery. In addition to these patients, there is a subset of patients who will develop peripartum cardiomyopathy.

Pathophysiology
Hypertrophic cardiomyopathy (HCM) is an autosomal dominant disease due to mutations of the cardiac sarcomere proteins, which result in asymmetric hypertrophy of the left ventricle, a nondilated left ventricular cavity, and preserved systolic function with impaired [[diastolic function[[.

Left ventricular outflow tract obstruction (LVOT) is present at rest in approximately 20% of patients.

Complications
Although most women with HCM with minimal or mild symptoms tolerate pregnancy well, risks in pregnancy include:
 * Sudden death, particularly in patients with severe outflow obstruction or other risk factors for sudden cardiac death.
 * Hemodynamic deterioration, particularly in those with moderate or severe symptoms before pregnancy.

Treatment
Management considerations during pregnancy, labor, and delivery include:
 * Beta-blockers and calcium channel blockers are safe in this population.
 * Avoid decreases in preload (straining, dehydration, etc.).
 * Avoid inotropes and vasodilators.
 * Tachycardia and reduced preload from valsalva can both adversely affect the HCM patient, so labor should be in a high-risk center.
 * Epidural anesthesia should be avoided due to the potential for hypotension.
 * Prostaglandins for the induction of labor is not advised, secondary to inherent vasodilatory effects.
 * General anesthesia is often employed, and asopressor agents and fluids can be given to treat hypotension.

Related Chapter

 * This section will primarily focus on hypertrophic cardiomyopathy (HCM) in pregnancy. For a more detailed discussion of hypertrophic cardiomyopathy, click here.