Epidemiological studies suggest that this disorder is common, afecting approximately 1 in 500 adults (Herrey, 2014; Maron, 2004). Characterized by cardiac hypertrophy, myocyte disarray, and interstitial ibrosis, the condition is caused by mutations in anyrone of more than a dozen genes that encode cardiac sarcomere proteins in up to 60 percent of afected patients. In such cases, inheritance is autosomal dominant, and genetic screening is complex (Elliott, 2014). Other genetic and nongenetic causes account for 5 to 10 percent of cases, and the cause is unknown in approximately 25 percent. The myocardial muscle abnormality is typified by let ventricular myocardial hypertrophy with a pressure gradient against let ventricular outflow. Diagnosis is established by echocardiographic identification of a hypertrophied and nondilated left ventricle in the absence of other cardiovascular conditions.
Most afected women are asymptomatic, but dyspnea, anginal or atypical chest pain, syncope, and arrhythmias may develop. Complex arrhythmias may progress to sudden death, which is the most frequent cause of death. Asymptomatic patients with runs of ventricular tachycardia are especially prone to sudden death. Symptoms usually worsen with exercise.
lthough limited reports suggest that pregnancy is well tolerated, adverse cardiac events are frequent. In one analysis of 271 pregnancies in 127 afected women, there were no maternal deaths. However, more than a fourth had at least one adverse cardiac symptom-including dyspnea, chest pain, or palpitations (Thaman, 2003). Based on one systematic review that included 237 women with hypertrophic cardiomyopathy who had a combined 408 pregnancies, Schinkel (2014) calculated a maternal mortality rate of 0.5 percent. Worsening of symptoms or other complications occurred in 29 percent, and 26 percent delivered preterm.
Management is similar to that for aortic stenosis. Strenuous exercise is prohibited during pregnancy. Abrupt positional changes are avoided to prevent reflex vasodilation and decreased preload. Likewise, drugs that evoke diuresis or diminish vascular resistance are generally not used. If symptoms develop, especially angina, 3-adrenergic or calcium-channel blocking drugs are given. The delivery route of the fetus is determined by obstetrical indications. Choice of anesthesia is controversial, and some authors consider general anesthesia the safest (Pitton, 2007). Neonates rarely demonstrate inherited lesions at birth.
This is characterized by left and/or right ventricular enlargement and reduced systolic function in the absence of coronary, valvular, congenital, or systemic disease known to cause myocardial dysfunction. Although there are many known causes of dilated cardiomyopathy-both inherited and acquired, the etiology remains undefined in approximately half of cases (Stergiopoulos, 2011). Some result from viral infections, including myocarditis and HIV (Barbaro, 1998; Felker, 2000). Other causes, which are potentially reversible, include alcoholism, cocaine abuse, and thyroid disease. Watkins and coworkers (2011) reviewed the many complex genetic mutations associated with inherited forms of dilated cardiomyopathy.
This disorder is similar to other forms of nonischemic dilated cardiomyopathy except for its unique relationship with pregnancy (Pyatt, 2011). Indeed, peripartum cardiomyopathy shares a genetic predisposition with both familial and sporadic idiopathic dilated cardiomyopathy (Ware, 2016). Currently, it is a diagnosis of exclusion following a concurrent evaluation for peripartum heart failure.