CARDIOVASCULAR JOURNAL OF AFRICA • Vol 22, No 2, March/April 2011
72
AFRICA
II was recorded in all subjects. The same cardiologists indepen-
dently reported each ECG.
Exclusion criteria included previous or current hypertension,
diabetes mellitus, thyrotoxicosis, history suggestive of congeni-
tal or valvular heart disease, or any other form of cardiac disease,
sickle cell disease and anaemia (PCV
<
30%) at the time of
recruitment.
Araoye
6
and Sokolow-Lyon
7
criteria were independently used
to assess for left ventricular hypertrophy (LVH):
Araoye criteria: R in lead I (RI)
>
12 mm, or
SV
2
+
RV
6
≥
35 mm,
with or without T-wave inversion/flattening in V
5
, V
6
.
Sokolow-Lyon criteria: SV
1
+
RV
5
(or RV
6
)
≥
35 mm
with or without T-wave inversion/flattening in V
5
, V
6
.
Corrected QT (QTc) was calculated for each patient using
Bazett’s formula;
8
a normal value in females is 0.37–0.44;
>
0.44
is prolonged.
9
In cases of incomplete data, an allowance was made for 10%
fall-out from the analysis. Data were compared between the
two groups. Data entry was into standard forms and statistical
analysis was performed. All the tests were two-sided with a 0.05
significance level set. Differences in age, parity and estimated
gestational age (EGA) were by
t
-test, with chi-square for other
parameters, using the Statistical Package for Social Sciences
(SPSS) Chic Ill. version 11. Relative risk (RR) and 95% confi-
dence interval (CI) were calculated using the method described
by Newcombe-Wilson.
10
Results
The age distribution in the two groups (pregnant and non-preg-
nant controls) was similar, with most women in the age group
20–35 years (91.3 vs 85.7%, respectively), as shown in Table 1.
However, most of the patients in the control group were nullipa-
rous (48/70, 68.6%), while parity in the pregnant group ranged
between one and three offspring (41/69, 59.4%) (Table 1). There
were 33, 28 and eight pregnant women in the expected gesta-
tional age groups of
<
28 weeks, 28–36 weeks and
>
36 weeks,
respectively. Table 2 shows the summary of clinical and ECG
parameters in the two groups with the relative risk, confidence
intervals and
p
-values.
Diastolic blood pressure (DBP) of less than 60 mmHg was
found in 64.7% of the pregnant group, versus 24.3% of the
control group (RR
=
2.685, CI
=
1.716–4.204,
p
<
0.005). When
the patients were grouped according to age, statistical signifi-
TABLE 1. AGEAND PARITY GROUP DISTRIBUTION
Pregnant (
n
=
69)
Non-pregnant (
n
=
70)
Age (years)
<
20
1
2
20–35
63
60
>
35
5
8
Parity
0
23
48
1–3
41
16
>
3
5
6
TABLE 2. SUMMARY OF CLINICALAND ECG FINDINGS
Pregnant (
n
=
69)
Non-pregnant (
n
=
70)
RR (95% CI)
p
-value
Mean pulse rate
84
±
11.05
75.27
±
8.51
–8.73 (–12.04– –5.42)
0.043
DBP
<
60 mmHg
64.7% (45)
24.3% (17)
2.685 (1.716–4.204)
<
0.005
SBP (90–120 mmHg)
80.9% (56)
78.6% (55)
1.033 (0.874–1.221)
0.704
Cardiac findings
41.2% (29)
12.9% (9)
3.156 (1.610–6.189)
<
0.0005
Mean ECG heart rate
88.34
±
11.46
75.16
±
12.22
–13.18 (–17.15– –9.21)
0.0215
Sinus tachycardia
8.7% (6)
2.9% (2)
3.044 (0.636–14.562)
0.266
Sinus bradycardia
0
5.7% (4)
–
0.132
PR
<
0.12 s
0
1.4% (1)
–
–
PR
>
0.20 s
1.5% (1)
2.9% (2)
0.507 (0.047–5.466)
0.999
QRS
>
0.12 s
0
1.4%
–
–
Normal QRS axis
100%
100%
–
–
LVH (RI
>
12 mm)
10.2% (7)
0
0.087 (0.019–0.155)
0.0189
All LVH criteria
18.8% (13)
7.1% (5)
2.638 (0.994–7.002)
0.0399
RVH
0
0
–
0
Rsr
′
(mostly lead III)
5.8% (4)
14.3% (10)
0.406 (0.134–1.232)
0.0964
Rsr
′
in avF
20.3% (14)
5.1% (4)
3.551 (1.230–10.252)
0.0105
ST segment – isoelectric line (J junction on isoelectric line)
97.1% (67)
75.7% (53)
1.283 (1.116–1.473)
<
0.0005
Mild ST elevation, (Negroid-pattern ST segment)
2.9% (2)
24.3% (17)
0.119 (0.029–0.497)
<
0.0005
T-wave inversion – lead III
±
any other lead
23.2% (16)
10.0% (7)
2.319 (1.018–5.284)
0.0364
Tall and broad T waves in V
2
– V
6
5.8% (4)
18.6% (13)
0.312 (0.107–0.910)
0.0215
APCS
4.3% (3)
2.9% (2)
1.522 (0.262–8.828)
0.987
VPCS
2.9% (2)
2.9% (2)
–
0.622
Path Q waves
0
0
–
–
APCS and VPCS together
7.3% (5)
5.8% (4)
1.268 (0.355–4.525)
0.982
Prolonged QTc
4.3% (3)
8.6% (6)
0.493, (–0.550–1.583)
0.505
Percentage of distribution (absolute number of patients). RR
=
relative risk, CI
=
confidence interval; DBP
=
diastolic blood pressure; SBP
=
systolic blood pressure; LVH
=
left ventricular hypertrophy; RVH
=
right ventricular hypertrophy; APCS
=
atrial premature contractions; VPCS
=
ventricular premature contractions.
