What is peripartum cardiomyopathy?
Peripartum cardiomyopathy (PPCM) is a form of heart disease that occurs during the last month of pregnancy or up to five months after giving birth. This disease is characterized by a weakened heart muscle, which causes the heart to eject less blood from the left ventricle with each contraction. The heart cannot supply enough blood to cells in the body, so other organs do not receive enough oxygen. This usually results in fatigue and shortness of breath. Other symptoms may include weakness, cough, chest discomfort, irregular heart beat or leg swelling.
PPCM is a relatively rare disease that occurs in women worldwide. Approximately 1,500 to 2,000 women develop this condition in the United States each year. PPCM may be more or less common in other countries, but it is difficult to know for certain due to limited data available.
How is PPCM diagnosed?
PPCM is sometimes difficult to diagnose because heart failure symptoms can mimic symptoms that typically occur during the third trimester of pregnancy and the early postpartum period.
- Shortness of breath, particularly at rest
- Inability to lie flat due to shortness of breath
- Awakening at night due to shortness of breath
- Persistent cough
- Feeling of heart racing or skipping beats (palpitations)
- Swelling of the feet, ankles, and/or legs
During a physical exam, doctors will listen for signs of fluid in the lungs, rapid heart rate and abnormal heart sounds. Doctors will also look for swollen neck veins and swollen legs.
Tests usually ordered include:
Blood tests to assess kidney, liver and thyroid function and electrolyte levels as well as a complete blood count and markers of cardiac injury and stress
An electrocardiogram (ECG) to record the heart rhythm
A chest x-ray to check for signs of fluid in/around the lungs
An echocardiogram (cardiac ultrasound) to determine if the heart muscle is weak and whether or not any other cardiac abnormalities are present. Heart muscle strength is assessed by the left ventricular ejection fraction (LVEF), which indicates how much blood the left ventricle pumps out with each contraction. A normal LVEF is usually between 55% to 70%.
A cardiac MRI is sometimes done to assess the left ventricular ejection fraction and to determine whether the cardiomyopathy is due to heart muscle inflammation (myocarditis) or some other abnormality. There are no cardiac MRI findings that are specific for diagnosing PPCM.
A heart biopsy may be performed if there is concern that the cardiomyopathy is due to myocarditis, but this occurs very rarely. There are no heart biopsy findings that are specific for diagnosing PPCM.
PPCM is diagnosed when the following three criteria are met:
- Heart failure symptoms develop in the last month of pregnancy or within 5 months of delivery.
- Heart pumping function is reduced, with a left ventricular ejection fraction (LVEF) less than 45%
- No other cause for heart failure with reduced LVEF can be found.
The severity of symptoms in patients with PPCM can be classified by the New York Heart Association system:
|Class I (mild):||No limitation of physical activity. Ordinary physical activity does not cause undue fatigue, shortness of breath or palpitations.|
|Class II (mild-moderate):||Slight limitation of physical activity. Comfortable at rest, but ordinary physical activity results in fatigue, hortness of breath or palpitations.|
|Class III (moderate):||Marked limitation of physical activity. Comfortable at rest, but less than ordinary activity causes fatigue, shortness of breath or palpitations.|
|Class IV (severe):||Unable to carry out any physical activity without discomfort. Fatigue, shortness of breath or palpitations at rest. If any physical activity is undertaken, symptoms worsen.|
What causes PPCM?
No unique cause for PPCM has been determined. Potential causes include inflammation in the heart muscle, viral infection, abnormal immune response, decreased antioxidant defenses and excessive prolactin (nursing hormone) production. Genetics may play a role, but no genetic abnormalities specific for PPCM have yet been found.
What are risk factors for PPCM?
Factors which have been proposed to increase the risk for PPCM include:
- Multiple pregnancies
Poor nutritional status
Black African ancestry
How can PPCM be treated?
The treatment goals for women with PPCM include:
1. Keep the lungs clear from fluid to reduce shortness of breath
2. Help the heart muscle recover as much as possible.
There are no treatments specifically developed to treat PPCM. Women with PPCM are generally treated with one or more of the following medications which have been proven to be effective in patients with other types of heart failure (weakened heart muscle).
- Angiotensin converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB)– Dilates (widens) the blood vessels to improve blood flow, which helps to decrease the amount of work the heart has to do; these medications also block angiotensin, a harmful substance in the blood that is produced as a result of heart failure
- Entresto– This medication combines two medications in one, both of which combine to relax blood vessels so that blood can flow more easily, making it easier for the heart to pump blood to the body
- Beta blocker– Slows the heart rate, which allows the left ventricle (the main pumping chamber of the heart) to fill more completely
- Diuretic– Decreases fluid retention
- Aldosterone antagonist– Blocks the harmful effects of aldosterone, a harmful substance in the blood that is produced as a result of heart failure
- Digitalis– Slows the heart rate and strengthens heart contractions, enabling the heart to pump more blood with each beat
- Anticoagulant– Thins the blood to prevent blood clots from forming in the heart
Women with PPCM are advised to eat a low-salt diet, restrict fluid intake, and remain as physically active as possible. They may be advised to weigh themselves daily in order to track fluid retention.
Women who smoke and drink alcohol are counseled to stop, since these habits may make heart failure symptoms worse and potentially harm the heart muscle.
Some women with PPCM, particularly those with very low LVEF at the time of diagnosis, may be advised to wear an external cardiac defibrillator vest for several months or to undergo a procedure to have an internal cardiac defibrillator (ICD) implanted to protect against complications from life-threatening arrhythmias.
In rare cases, women may have a heart-assist device placed in order to help the heart pump more blood or undergo a heart transplant.
What is the prognosis?
Recent research studies have shown that the LVEF of more than half the women diagnosed with PPCM returns to normal within 6 to 12 months after diagnosis. The heart function of some of the women whose ejection fraction does not normalize within 1 year after diagnosis may continue to improve up to several years after diagnosis. Some women with PPCM, however, never completely regain normal heart function. A very small percentage of women with PPCM will die, usually due to complications from having a severely weakened heart muscle or an abnormal heart rhythm.
What is being done to learn more about PPCM?
Researchers continue to search for the cause of PPCM in order to try to prevent this disease and to develop new medications that can help women with PPCM recover their heart function faster and more completely. An important aspect of the PCA’s mission is to raise funds to support researchers who are working to prevent and find a cure for PPCM and to encourage women with PPCM to participate in research studies.