CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 10, November 2012
AFRICA
557
with promising results.
45
The process of progression from acute
myocarditis to dilated cardiomyopathy was recently elucidated
by Kawai.
46
Peripartum cardiomyopathy (PCM)
PCM commonly occurs during the last trimester of pregnancy
and the first six months after delivery. Risk factors that have been
reported in the literature are:
37,47-50
•
black race
•
advanced maternal age
•
twin pregnancies
•
gestational hypertension
•
long-term tocolysis.
Reports from Haiti have shown that partial improvement of
systolic function occurred in the first year of follow up.
50
In fact a
third of their women with PCM recovered fully within five years.
Mortality rates were 15% in the first six months and 42% during
25
years of follow up. The Hausas in the northern part of Nigeria
have the highest known incidence of PCM in the world – about
13%
of all female admissions at the Ahmadu Bello University
Teaching Hospital, Zaria.
51-54
A wide range of diseases has been advanced as the cause of
myocardial damage of these women. They include myocarditis,
hypertension, abnormal immune response to pregnancy,
impaired cardiac (systemic) microvasculature, increased myocyte
apoptosis, cytokine-mediated inflammation, selenium deficiency
(
Keshan disease), lying on heated mud beds after taking two hot
baths in addition to excessive consumption of a special porridge
to which as much as 30 g/day of potash (kanwa) has been added
(
Zaria cases), genetic predisposition, increased adrenergic tone
leading to myocardial stunning, and excessive production of
prolactin.
55
Recent studies have also shown that unbalanced peri/
post partum is linked to proteolytic cleavage of prolactin,
which turns it into a potent anti-angiogenic, pro-apoptotic and
pro-inflammatory factor. These observations tend to suggest that
prolactin cleavage could operate as a specific pathomechanism
for the development of PCM.
55,56
Bromocriptine has been shown
to be beneficial in reducing the raised levels of prolactin found
in some of the women, improving their left ventricular function.
57
The plasma marker of apoptosis, Fas/Apo-1 has also been
shown to be elevated in patients with PCM,
42,45
while troponin T
levels have been found to be useful in predicting the presence of
persistent left ventricular dysfunction in patients.
58
Baseline Fas/
Apo-1 levels and higher NHYA at presentation were found to be
the only predictors of mortality, while MRI using late gadolinium
enhancement can be useful in evaluating the extent of myocardial
damage and predict the outcome of the disease.
46,59,60
Withmolecular studies, viral genomic materials of enterovirus,
parvovirus B
19
,
human herpes virus 6, Epstein-Barr virus and
cytomegalovirus have been identified in the heart muscle of
some women with PCM.
61-63
On the contrary, Cenac
et al.
64
found no evidence of viral myocarditis in Niger, West Africa.
Sanderson
et al
.,
37
O’Connell
et al
.
65
and Midei
et al
.
66
on the
other hand found evidence of myocarditis in biopsy materials
of the women they studied. In fact, Midei
et al
.
66
reported that
as many as 78% of newly diagnosed patients with PCM seen by
his group had myocarditis and resolution was associated with
improvement of left ventricular function.
Familial dilated cardiomyopathy
Familial forms of dilated cardiomyopathies have been well
summarised by Maron
et al
.
17
It is estimated that they constitute
20
to 35% of cases of DCM. They are genetically heterogenous
but the predominant mode of inheritance is autosomal dominant,
with X-linked autosomal recessive and mitochondrial inheritance
occurring less frequently. Many of the mutant genes that
are linked to autosomal dominant DCM also encode the
same contractile sarcomeric proteins that are responsible for
hypertrophic cardiomyopathy.
According to Maron
et al
.,
17
DCM is also caused by a number
of mutations in other genes encoding cytoskeletal/sarcolemmal,
nuclear envelope, sarcomere and transcriptional co-activator
proteins. The most common of these is the lamin A/C gene,
which is also associated with conduction system disease, and
encodes a nuclear envelope intermediate filament protein.
In Africa, the first report of familial DCM was from Uganda
where a set of twin brothers was reported to have had the
disease.
67
Reports of familial cases have also come from South
Africa. A case of familial DCM with prominent ventricular
arrhythmias was reported by Brink
et al
.
68
while Przybojewski
et al.
69
described two brothers of Afrikaner ancestry with
unexplained DCM. Cases of DCM have been linked with
progressive familial heart block types I and II.
70-72
There were also
reports of DCM in two brothers,
68
and a case of microcephaly
associated with DCM.
72
Mayosi
et al.
73
has also shown that actin mutations do not play
a major role in DCM but a mitochondrial DNA susceptibility
gene increases the risk of DCM in the general population. Other
studies from South Africa evaluated the role of mutations in
signaling pathway proteins, in particular, polymorphisms in
the angiotensin-converting enzyme and beta-adrenoreceptor
subtypes in the progression of DCM.
74
Malnutrition
Initial reports of DCM from South Africa suggested that
the disease was caused by malnutrition. The patients whom
Gillanders
5
and Higginson
et al
.
75,76
studied improved when their
diet was changed to what was described as a ‘balanced’ one. This
view has been discarded as Gillanders’ experiments could not be
reproduced.
In our study, we found that patients withDCMhad significantly
lower serum albumin levels compared with controls, irrespective
of whether they consumed alcohol or not. This was attributed to
hepatic dysfunction caused by congestive cardiac failure.
29
Haemosiderosis
Consumption of iron in excess from iron-containing beer (Bantu
haemosiderosis) has been suggested as a potentially reversible
causative factor of DCM.
75
It has also been found that the ‘poor
correlation of cardiac and hepatic iron deposits with heart
disease’ might have led to the under-recognition of dietary iron
overload as an important factor in the pathogenesis of DCM.
77
High levels of serum ferritin have been found in patients with
DCM compared with patients with heart failure from other
causes, and about 50% of the patients had ferritin levels above
500
ng/ml.
30
