Peripartum cardiomyopathy

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

Synonyms and keywords: Meadows syndrome

Overview

Peripartum cardiomyopathy (PPCM) is a form of dilated cardiomyopathy that is defined as a deterioration in cardiac function presenting between the last month of gestation and up to five months post-partum.

As with other forms of dilated cardiomyopathy, PPCM involves decrease of the left ventricular ejection fraction with associated congestive heart failure and increased risk of atrial and ventricular arrhythmias and even sudden cardiac death.

The definition of PPCM includes four criteria, three clinical and one echocardiographic:

1. PPCM occurs during last month of pregnancy or first five months after delivery.
2. Absence of an identifiable cause for cardiac failure.
3. Absence of heart disease prior to last five months of pregnancy.
4. Echocardiographic criteria -severe left ventricular systolic dysfunction, demonstrated by ejection fraction less than 45% or M-mode fractional shortening less than 30%(or both) and left ventricular end-diastolic dimension >2.7cm/m².

Etiology

The etiology of peripartum cardiomyopathy is not clearly known. Research suggests that cardiac angiogenic imbalance may play a role in peripartum cardiomyopathy.

Cardiac Angiogenic Imbalance and Peripartum Cardiomyopathy

Researchers indicated a two hit combination as the cause of peripartum cardiomyopathy. This includes:

1. Systemic anti-angiogenic signals during late pregnancy like elevated sFTL1 from the placenta which binds to and neutralizes soluble members of the VEGF(vascular Endothelial Growth Factor) family , elevated prolactin from the pituitary which on inappropriate cleavage by reactive oxygen species (ROS) forms a potent anti-angiogenic 16-kDa form, and excess angiotensin II signalling.
2. A host susceptibility caused by

• Insufficient local pro-angiogenic defenses in the heart. This includes:

• A decrease in the transcriptional coactivator PGC-1α. PGC-1α drives mitochondrial biogenesis, regulates angiogenic programming and increases ROS scavenging.
• Abnormal or absent STAT3. STAT3 is responsible for protection against ROS production.

• Genetically predisposed
• Immune activated
• viral infection induced
• auto-antibody induced
• Inflammatory states of the heart induced.

PGC-1α knockout mice (mice in which all or part of gene was eliminated or inactivated by genetic engeneering) were completely rescued from developing peripartum cardiomyopathy by administering VEGF and Bromocriptine which provides strong evidence that cardiac angiogenic imbalance can lead to ultimate onset of peripartum cardiomyopathy.

Epidemiology

The reported incidence fluctuates globally but is higher in developing countries. It usually affects 1 in 300 to 1 in 3000 pregnancies. Nigeria(1%) and Haiti(0.3%) are examples of geographic hot spots of high incidence. In the Unites States, the incidence ranges between 1 in 3000 to 1 in 4000 deliveries.

Risk Factors

The incidence of peripartum cardiomyopathy is increased in women over the age of 30, in twin pregnancies, in multiparous women, in women with gestational hypertension, those who have received tocolytic therapy, in maternal cocaine abuse and in african americans.

Clinical Features (History)

Pregnancy itself brings about some features that suggest cardiac insufficiency. Symptoms such as dyspnoea, dizziness, orthopnoea and decreased exercise tolerance are often normal findings in pregnancy.

Moreover, the normal cardiac physiology changes dramatically in the gravid female. Blood volume increases progressively from 6-8 weeks gestation (pregnancy) and reaches a maximum at approximately 32-34 weeks with little change thereafter. During the first trimester cardiac output is 30-40% higher than in the non-pregnant state; there is also an approximately 35% increase in stroke volume, a 15% increase in HR and a steady decrease in vascular resistance.

Since this is an excellent cover for a developing condition, often there are no extreme or notable symptoms until several days post-partum when the most notable symptoms become pulmonary edema with resultant breathing difficulties(dysnopea), serious energy depletion performing simple tasks such as walking, standing or even sitting up for extended periods, and sudden cardiac arrest.

If these conditions appear after a woman has been discharged from clinical care the possibility of mortality is greatly increased.

The dyspnoea is described usually by women as the inability to take a deep breath to get enough air into her lungs. It is thought that the hormonally mediated (progesterone) hyperventilation seen in pregnancy is the cause.

In PPCM the symptoms secondary to acute onset of heart failure seen are similar to patients with systolic dysfunction who are not pregnant. These symptoms include cough, orthopnoea, paroxysmal nocturnal dyspnoea, fatigue, palpitations, haemoptysis and chest pain. These symptoms mimic many normal pregnant women who cannot tolerate lying flat, have significant pedal edema, complain of shortness of breath and dyspnea but have no heart disease.

The challenge facing physicians is to differentiate between these two groups and diagnose women with PPCM sooner than later as early intervention has shown benefit and may save lives.

The following is a screening tool developed by James D. Fett, MD, which may be useful to patients and medical professionals in determining the need to take further action to diagnose symptoms:

Focused medical history for PPCM screening, looking for early symptoms of heart failure, during last month of pregnancy:
1. Orthopnea (difficulty breathing while lying flat):
a.) None = 0 points; b.) Need to elevate head = 1 point; c.) Need to elevate upper body 45° or more = 2 points
2. Dyspnea (shortness of breath on exertion):
a.) None = 0 points; b.) Climbing 8 or more steps = 1 point; c.) Walking on level = 2 points
3. Unexplained cough:
a.) None = 0 points; b.) Night-time = 1 point; c.) Day and night = 2 points
4. Swelling (pitting edema) lower extremities:
a.) None = 0 points; b.) Below knee = 1 point; c.) Above and below knee and/or hands/face = 2 points.
5. Excessive weight gain during last month of pregnancy:
a.) Under 2 pounds per week = 0 points; b.) 2 to 4 pounds per week = 1 point; c.) over 4 pounds per week = 2 points.
6. Palpitations (sensation of irregular heart beats):
a.) None = 0 points; b.) When lying down at night = 1 point; c.) Day and night, any position = 2 points
Scoring and Action:
0 - 2 = low risk—continue observation
3 - 4 = mild risk—consider doing blood BNP and CRP; echocardiogram if BNP and CRP are elevated
5 or more = high risk—do blood BNP, CRP, and echocardiogram

Diagnosis

Echocardiography

Peripartum cardiomyopathy is diagnosed only when the following criteria are met: left ventricular ejection fraction (LVEF) <0.45 or M-mode fractional shortening <30% (or both) and end-diastolic dimension >2.7 cm/m².

Echocardiography is essential for diagnosis. It is effective and obviates the need for cardiac catheterization.

It is also useful to diagnose mural thrombus, mitral regurgitation, tricuspid regurgitation and pericardial effusion.

Prompt echocardiography in all symptomatic pregnant patients can help to reveal patients with undiagnosed peripartum cardiomyopathy earlier in the course of the disease, thereby leading to earlier institution of care and to improvement of outcomes.

Prognosis

Mortality rates range anywhere between 9% and 56%. About 50 to 60 percent of women with PPCM demonstrate improvement or total recovery in their left ventricular function within 6 months of diagnosis. The remainder tend to have either stabilization of their ventricular function or worsening (requiring cardiac transplantation).

Women are strongly discouraged from subsequent pregnancies as numerous studies have demonstrated recurrence of the disease.

The New York Peripartum Cardiomyopathy Study Group is an ongoing registry seeking to answer many of the questions left unanswered because of the rarity of the disease. For more information about the study, one can visit

Treatment for this disease varies widely reflecting the range of severity. While some patients with severe left ventricular dysfunction (less than 35%) may proceed to cardiac tranplant or require an automated internal cardiac defibrillator (AICD) and standard heart failure therapy, others may return to normal cardiac function and reuqire little, if any, additional medical therapy. However, all women should be strongly discouraged from having subsequent pregnancies.

Treatment

Treatment for the disease is similar to treatment for congestive heart failure apart from concerning the adverse effect of treatment on fetus or breast-feeding infant.

Delivery is the recommended overall treatment to decrease the volume load, improve ventricular function and simplify the medical management of these patients.

References

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