In this video, I discuss peripartum cardiomyopathy which is characterised by the development of heart failure in pregnancy. What is peripartum cardiomyopathy?
This is also known as pregnancy-associated cardiomyopathy and is a relatively uncommon condition which affects women either late during pregnancy or within 5 months of giving birth and is characterised by the development of heart muscle weakness (heart failure)
To be diagnosed with peripartum cardiomyopathy, 3 criteria need to be met
1) Development of heart failure towards the end of pregnancy or within the first five months after delivery
2) There is no other identifiable cause of heart failure
3) On echocardiography, the ejection fraction is less than 45% (Remember the normal ejection fraction is about 60%) How common is this condition? It can affect any women of any ethnicity but there are significant differences based on geography In Zaria Nigeria, it affects 1:100 live births (In Zaria, Nigeria) In the US it affects 1:1000-1:4000 live births In Japan it affects 1:20000 live births.
These figures may not be completely accurate because they only capture those women who had the severest forms of the condition. It is possible that women who have very mild symptoms don’t actually complain and therefore never get investigated.
Why does it occur? The truth is that we don’t know for sure. There are a variety of different factors that may be responsible. It is also worth knowing that pregnancy-induced cardiomyopathy is also known as Zaria syndrome because it has the highest incidence in this region and this may be because of a local Hausa custom of eating Kanwa (a dry lake salt for 40 days after delivery). Salt retains water and causes an increase in the amount of work the heart has to do to pump blood around and this can lead to an excessive amount of strain on the heart and this, therefore, can lead it to weaken.
Other factors which may be responsible include: Genetics: We know that there is familial clustering of peripartum cardiomyopathy with dilated cardiomyopathy meaning that there can be a susceptibility to development of heart muscle weakness in families and sometimes it becomes obvious during pregnancy but in other members of the family heart muscle weakness is seen in the absence of pregnancy suggesting that there is a genetic vulnerability to the heart weakening under some kind of stressor.
Pregnancy is definitely a stressor because the blood volume increases by about 50% and therefore the amount of work that the heart has to do goes up substantially. We also know that the African genomic ancestry may be a risk factor and this may be the reason we see it more commonly in Africa, Haiti and in black patients in the USA.
Black patients also seem to have a delay in recovery and a small proportion normalise with treatment compared to white patients. Prolactin: Prolactin is a hormone which enables females to produce milk. There is some evidence that there is some form of alteration in prolactin processing and this can cause more stress on the heart and this could contribute to the development of heart failure.