CLICK TO VIEW OTHER SECTIONS RELATED TO THIS TOPIC:
Management Strategies
Preconception counseling/Contraceptive methods
Ideally, a comprehensive cardiovascular examination should be undertaken before embarking on pregnancy. This includes a careful history and physical examination, an echocardiogram and an electrocardiogram. The additional prognostic benefit of cardiopulmonary exercise testing has not been defined, but may be helpful in some cases.
Asymptomatic women generally do well through pregnancy. Women with symptoms prior to pregnancy are at higher risk for complications (decline to NYHA functional class III-IV, pulmonary edema or arrhythmias) during pregnancy. Women with clinical heart failure should be advised about the high risk of pregnancy, as they may be unable to tolerate the increased hemodynamic load.
Decisions regarding internal cardioverter defibrillator (ICD) placement for prevention of sudden cardiac death and invasive therapies to decrease symptoms (i.e. surgical myectomy, alcohol ablation and biventricular pacing) should be made prior to pregnancy.
Transmission of heart disease to offspring should be discussed. The risk of transmission of HCM is approximately 50%, compared to a background risk of any congenital heart disease of 1%.
A discussion about contraceptive methods is appropriate in all women with HCM. Combined oral contraceptives (estrogen/progestin) are not advised in women with cardiomyopathy and left ventricular ejection fractions < 30%. (see Contraception)
Medication use should be reviewed if a woman is contemplating pregnancy or is pregnant. The MOTHERISK website is an excellent resource.
Ante-partum Care
Coordinated care with a heart specialist and a high-risk obstetrician should be implemented. The frequency of assessments (clinical and echocardiographic) during pregnancy should be determined on the basis of the maternal functional status, the family history of the women, the systolic and diastolic ventricular function, the degree of outflow tract obstruction and the severity of mitral regurgitation.
Close cardiovascular monitoring, with specific attention to volume status, is important throughout pregnancy and the peripartum period. Volume depletion should be avoided as it can precipitate left ventricular outflow tract obstruction in women with hypertrophic obstructive cardiomyopathy. In contrast, volume overload should be avoided among women with heart failure and/or systolic/diastolic left ventricular dysfunction. Treatment for symptomatic heart failure may be necessary in some women.
Atrial fibrillation can be treated medically or with DC cardioversion when women are unstable or unresponsive to medical therapy. (see Arrhythmias) Women treated with warfarin prior to pregnancy should be seen by a Hematologist to develop an anticoagulation plan for the pregnancy.
Women should be offered fetal echocardiography at approximately 20 weeks gestation.
Labour and Delivery
Labour and delivery should be planned carefully with a multidisciplinary team well in advance. It is important to communicate the delivery plan to the woman and to other physicians involved in her care. The best delivery plan is not useful if information is not readily available when needed.
Generally, vaginal deliveries are recommended unless there are obstetric indications for a cesarean delivery. Good pain management for labour and delivery is very important in order to minimize maternal cardiac stress. Regional anesthesia should be carefully administered to avoid hypotension as vasodilation is poorly tolerated. To decrease maternal expulsive efforts during the second stage of labour, forceps or vacuum delivery is often utilized. To decrease potential harmful complications from difficult mid cavity-assisted delivery, uterine contractions are often utilized to facilitate the initial descent of the presenting part. Oxytocin can induce vasodilation and arterial hypotension and should be administered with great care if truly needed. Hypovolemia or blood loss should be aggressively corrected.
The need for maternal cardiac monitoring at the time of labour and delivery is dictated the women’s functional status, the degree of ventricular dysfunction, and the degree of left ventricular outflow tract obstruction. Most women with HCM do not require invasive monitoring. To detect potential arrhythmias early, continuous electrocardiographic monitoring may be helpful in some instances.
In general, endocarditis prophylaxis at the time of labour and delivery is not recommended in women with HCM. However, some experts continue to administer antibiotics because they feel that the risks of adverse reactions to antibiotics are small and the risk of developing endocarditis has major health consequences.
Post-partum Care
The hemodynamic changes of pregnancy may take up to six months to normalize. Women should be seen early after pregnancy (usually within 6-8 weeks). The frequency of additional follow up visits should be dictated by the clinical status of the women.
