Peripartum cardiomyopathy

Peripartum cardiomyopathy
Other names	Post-partum cardiomyopathy[1]
Specialty	Obstetrics & Gynecology, Cardiology
Symptoms	orthopnea, swollen ankles or feet, cough, chest pain, palpitations, fatigue
Complications	Thromboembolic events, Cardiogenic Shock
Usual onset	In the last month of pregnancy or up to 5 months postpartum
Duration	Varies
Risk factors	Maternal age 35+; high blood pressure; multiple gestations
Differential diagnosis	Takotsubo Cardiomyopathy, Familial Cardiomyopathy, Pre-existing Cardiomyopathy, Valvular Heart Disease, Congenital Heart Disease

Peripartum cardiomyopathy (PPCM) is a form of dilated cardiomyopathy that is defined as a deterioration in cardiac function presenting typically between the last month of pregnancy and up to six months postpartum. As with other forms of dilated cardiomyopathy, PPCM involves systolic dysfunction of the heart with a decrease of the left ventricular ejection fraction (EF) with associated congestive heart failure and an increased risk of atrial and ventricular arrhythmias, thromboembolism (blockage of a blood vessel by a blood clot), and even sudden cardiac death. In essence, the heart muscle cannot contract forcefully enough to pump adequate amounts of blood for the needs of the body's vital organs.^{[2][3][4][5][6]}

PPCM is a diagnosis of exclusion, wherein patients have no prior history of heart disease and there are no other known possible causes of heart failure. Echocardiogram is used to both diagnose and monitor the effectiveness of treatment for PPCM.^{[2][3][4][5][6]}

The cause of PPCM is unknown. Currently, researchers are investigating cardiotropic viruses, autoimmunity or immune system dysfunction, other toxins that serve as triggers to immune system dysfunction, micronutrient or trace mineral deficiencies, and genetics as possible components that contribute to or cause the development of PPCM. There is a relation with eclampsia and hypertension during pregnancy.^[2][7][4][8]

The process of PPCM begins with an unknown trigger (possibly a cardiotropic virus or other yet unidentified catalyst) that initiates an inflammatory process in the heart. Consequently, heart muscle cells are damaged; some die or become scar tissue. Scar tissue has no ability to contract; therefore, the effectiveness of the pumping action of the heart is decreased. Also, damage to the cytoskeletal framework of the heart causes the heart to enlarge, stretch or alter in shape, also decreasing the heart's systolic function or output. The initial inflammatory process appears to cause an autoimmune or immune dysfunctional process, which in turn fuels the initial inflammatory process. Progressive loss of heart muscle cells leads to eventual heart failure.^[9]

There has been increased research into the "toxic hormonal environment" that generates in late pregnancy as a contributor to the development of PPCM. Prolactin levels increase during late pregnancy and in the 6 weeks following birth. The 16 kilodalton N-terminal fragment of prolactin hormone has been implicated to have a causal role in genetically susceptible individuals. Thus, therapeutic interventions that block the prolactin pathway and prevent the generation of this fragment are being investigated as potential treatments to stop disease progression in PPCM.^[10]

Special considerations should be made for delivery when PPCM diagnosis is made before birth. A multi-disciplinary team should be assembled including experts in obstetrics, cardiology, maternal fetal medicine, and anesthesiology. Stable patients can be delivered vaginally unless there are other obstetric reasons for cesarean section. Attempts to stabilize the mother to delay birth and minimize potential complications of premature birth is a reasonable strategy. Following delivery, due to the increase in venous return, patients need to be closely monitored for fluid overload and pulmonary edema.^[11]