CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 6, July 2012
AFRICA
323
for example, technical and cost issues remain that prohibit their
use. In settings such as sub-Saharan Africa where resources are
scarce but the incidence of PPCM is high, the advantages of
finding alternative screening tools for this condition that truncate
the need for more extensive investigations, while being simple
and inexpensive to apply, are abundantly clear.
2,14
Although there is a paucity of electrocardiographic
data specifically relating to PPCM, an ‘abnormal’ 12-lead
electrocardiogram (ECG) is common in individuals with HF
syndrome, with common anomalies including supraventricular
arrhythmias, bundle branch block, and sinus bradycardia.
15
Given
the above, we undertook a prospective, pilot study of the 12-lead
ECG in a consecutive cohort of newly diagnosed women with
PPCM in South Africa. Specifically, the primary aim of this
study was to describe the baseline ECG characteristics in PPCM
patients, noting the type and prevalence of major and minor ECG
abnormalities. We also sought to analyse six-month follow-up
ECGs (where available) of PPCM patients to determine potential
ECG correlates of persistent LV dysfunction and/or clinical
stability, where possible, as repeat ECGs are not part of the
routine follow up of PPCM patients.
Methods
Consecutive patients presenting with
de novo
PPCM to two
tertiary centres in South Africa (Chris Hani Baragwanath
Hospital, Johannesburg, and Groote Schuur Hospital, Cape
Town) between January 2003 and August 2008 were studied.
Patients were referred from primary and secondary health
facilities, as well as internally from other departments. Only
patients aged
≥
17 years who fulfilled the diagnostic criteria for
PPCM
4
were considered eligible for the study. For recruitment,
previously described
16
inclusion and exclusion criteria had to be
met.
Ethical approval was obtained from each of the local
ethical committees of the universities of Cape Town and the
Witwatersrand, respectively, prior to the commencement of the
study. This study complied with all the requirements of the
Declaration of Helsinki. All patients were offered treatment and
follow up as per the local standard of tertiary care.
A total of 78 women presenting with PPCM were studied.
Of these, 56% had follow-up ECG data and were included in
the comparative study analyses. Of those patients who had
not had six-month ECGs (
n
=
34), three patients died (3.9%).
Importantly, patients with repeat six-month ECG data did not
differ significantly with respect to baseline heart rate, NYHA
functional class, and left ventricular ejection fraction (LVEF)
from the remaining cohort.
All patients with the provisional diagnosis of PPCM
underwent a thorough medical interview and examination,
and were investigated to confirm the diagnosis at baseline. All
patients had a 12-lead ECG and echocardiography. Additional
investigations were performed on a case-by-case basis. Data
were captured on standardised case report forms.
A 12-lead resting ECG was performed by a trained technician
and analysed by a reviewer blinded to all clinical data (GL), using
the Minnesota code classification system.
17
The code allows
systematic classification of Q and QS patterns, axis deviation,
R waves, ST depression and elevation, T-wave changes, along
with conduction abnormalities in both atria and ventricles.
17,18
The abnormalities detected by the Minnesota code were pooled
into major abnormalities and minor variations from the ‘normal’
12-lead ECG using the classification system previously applied
by de Bacquer and colleagues
19
(Table 1). Separate analyses for
ST-segment depression, arrhythmia or atrio-ventricular (AV)
block, bundle branch block and left-axis deviation were also
performed.
Standard methods for two-dimensional Doppler transthoracic
echocardiography were applied as per the American Society
of Echocardiography guidelines.
20
LV systolic dysfunction was
defined by echocardiographic documentation of left ventricular
ejection fraction (LVEF)
≤
45%. All studies were saved onto
hard-drive facilities, and a random sample of these was reviewed
by a cardiologist blinded to the clinical details of these patients,
to confirm the accuracy of parameters describing cardiac
structure and function.
Statistical analyses
All data analyses were performed with STATA-8.
21
For numerical
variables, we report on the mean [standard deviation (SD)]
TABLE 1. MAJORABNORMALITIESAND MINOR 12-LEAD
ECGVARIATIONS BASED ON MINNESOTA CODING
Major ECG abnormality
Minor ECG variations
Q-wave abnormalities
Borderline Q waves
ST-segment depression
Left- or right-axis deviation
T-wave inversion
High-amplitude R waves
2
o
or 3
o
AV block
Borderline ST-segment depression
Complete LBBB or RBBB T-wave flattening
Frequent premature atrial or
ventricular beats
Low QRS voltage
Atrial fibrillation or flutter
AV
=
atrio-ventricular; LBBB
=
left bundle branch block; RBBB
=
right bundle branch block. (Adapted from de Bacquer
et al
., 1998).
19
TABLE 2. BASELINE CLINICALAND DEMOGRAPHIC
PROFILE
Socio-demographic profile
Mean age (years)
29
±
7*
Proportion black African (%)
90
Obstetric profile
Median parity
2 (IQR 1–3)**
Median postpartum period at presentation
(days)
18 (IQR 6–30)**
Clinical presentation
Proportion with NewYork Heart Associa-
tion functional class III or IV (%)
64
Median body mass index (kg/m
2
)
24.3 (IQR 22.7–27.5)**
Mean pulse rate
99
±
19*
Blood pressure (mmHg)
Mean systolic
Mean diastolic
116
±
20*
76
±
14*
2D Doppler echocardiography
Median intra-ventricular septal thickness
in diastole (cm)
Mean left ventricular end-diastolic diam-
eter (cm)
Mean ejection fraction (%)
0.9 (IQR 0.8–1.1)**
5.8
±
0.7*
30.5
±
9*
*Standard deviation (
±
SD); **interquartile range (IQR).
