CARDIOVASCULAR JOURNAL OF AFRICA • Vol 21, No 1, January/February 2010
22
AFRICA
part of the ongoing care of known hypertensive patients.
Echocardiography was performed on all the subjects using a
Suis Apogee machine and a 3.5-MHz probe. Two-dimensional
colour Doppler and pulse-wave Doppler were carried out.
Echocardiography was done according to the American Society
of Echocardiography guidelines.
11
Two-dimensional guided
M-mode echocardiograms were used for the measurement of the
left ventricular internal dimension, interventricular septal thick-
ness and left ventricular posterior wall thickness during diastole,
according to the American Society of Echocardiography guide-
lines.
11
LVM was calculated from measurements of the left ventricle
(LV) using the equation:
LVM (g)
=
0.81 [1.04 (interventricular septal thickness
+
posterior wall thickness
+
LV end-diastolic internal dimension)
3
– (LV end-diastolic internal dimension)
3
]
+
0.6.
12
LVM index (LVMI) was calculated as LVM/height (m).
2.7
Correcting LVM for height
2.7
minimises the effect of gender,
race, age and obesity on the validity of various parameters for the
diagnosis of left ventricular hypertrophy.
13,14
One adult criterion
for LVH is LVMI
>
51 g/m
2.7
. As reported by de Simone
et al
.,
15
adult patients with hypertension and LVMI
>
51 g/m
2.7
have been
found to be at a fourfold greater risk of cardiovascular morbidity
outcomes. LV geometry was determined after calculation of the
relative wall thickness (RWT) using the formula (2
×
posterior
wall thickness)/LV end-diastolic internal dimension.
16
RWT was
considered abnormal if it was
≥
0.45.
16
Four left ventricular geometric patterns were described:
normal geometry, concentric remodelling, eccentric hypertro-
phy and concentric hypertrophy. LV geometry was defined as
concentric hypertrophy (elevated LVMI and RWT), concentric
remodelling (normal LVMI and elevated RWT), eccentric hyper-
trophy (increased LVMI and normal RWT) and normal geometry
(normal LVMI and RWT). LV ejection fraction was calculated
using Teichholz’s formula.
17
Statistical analysis was done using the Statistical Package for
Social Sciences, SPSS 15.0 (Chicago Ill.) Quantitative data were
summarised using means
±
standard deviation (SD) while quali-
tative data were summarised using percentages and proportions.
The Student’s
t
-test and chi-squared test were used as appropri-
ate for intergroup comparisons. Values of
p
<
0.05 were taken as
statistically significant.
Results
Table 1 shows the distribution of geometric patterns in the males
and females in the study group. Abnormal geometry was more
likely to occur among the males. Only 12.4% of males and
21.3% of females had normal geometry. The commonest abnor-
mal geometry was concentric hypertrophy, occurring in 44.24%
of males and 29.3% of females. As shown in Table 2, those with
abnormal geometry were more likely to be older and had a longer
duration of hypertension than those with normal geometry. They
were also more likely to have a higher systolic and diastolic
blood pressure than those with normal geometry.
Table 3 shows the echocardiographic parameters in the study
population. The mean left atrial dimension was highest among
those with eccentric hypertrophy. Ejection fraction (EF) and frac-
tional shortening (FS) were lower among subjects with abnormal
geometry compared with those with normal geometry, although
it was not statistically significant. Mean iso-volumic relaxation
time (IVRT) was highest among subjects with eccentric hyper-
trophy.
The mean left ventricular ejection time was reduced among
those with abnormal geometry compared with those with normal
geometry. Left ventricular dimensions (in both diastole and
systole), left ventricular mass (LVM), relative wall thickness
(RWT) and left ventricular mass index (LVMI) were statistically
different between subjects with normal and abnormal geometry,
as shown in Table 3. As shown in Table 4, hypertensive subjects
with abnormal geometry had reduced left ventricular systolic
function, as evidenced by reduced aortic valve and left ventricu-
lar output velocity–time intervals.
Discussion
LVH has been recognised as an important predictor of adverse
cardiovascular events, such as malignant arrhythmias, sudden
cardiac death, heart failure and coronary heart disease.
18-20
Abnormal left ventricular geometry has been shown recently to
represent a subtle form of advanced LVH and is associated with
systolic and diastolic dysfunction.
21,22
These studies evaluated the
prognostic significance of left ventricular geometrical patterns
on the cardiovascular risk of hypertensive subjects. Concentric
remodelling and concentric hypertrophy were reported in the
Ochner studies to be associated with increased adverse cardio-
vascular risks.
21
All-cause mortality has been reported to increase
two-fold in concentric remodelling (similar to eccentric hyper-
trophy) and is further increased in concentric hypertrophy.
22-24
This study demonstrated increased prevalence of left ventricu-
lar hypertrophy and abnormal left ventricular geometric patterns
among treated Nigerian hypertensive subjects. This relatively
increased prevalence has been documented among blacks worl-
wide.
25,26
Concentric remodelling and concentric hypertrophywere
TABLE 1. DISTRIBUTION OF LV GEOMETRY
PATTERNS IN BOTH GENDERS
Male (
n
=
113) (%) Female (
n
=
75) (%)
p
CH
50 (44.2)
22 (29.3)
<
0.05*
CR
32 (28.3)
21 (28.0)
>
0.05
EH
17 (15.0)
16 (21.3)
>
0.05
N
14 (12.4)
16 (21.3)
>
0.05
TOTAL
113 (100)
75 (100)
<
0.05*
CR: concentric remodelling, CH: concentric hypertrophy, EH: eccen-
tric hypertrophy, N: normal geometry. *Statistically significant.
TABLE 2. CLINICAL CHARACTERISTICS OF
LV GEOMETRY PATTERNS
Variable
CH
EH
N
CR ANOVA
Age
57.89
±
9.7 54.5
±
10.7 56.6
±
11.0 51.5
±
12.1 0.05
Duration 8.0
±
8.43 5.53
±
7.3 6.17
±
7.22 4.35
±
5.1 0.165
BSA
1.83
±
0.18 1.79
±
0.19 1.81
±
0.16 1.87
±
0.18 0.40
SBP
152.13
±
24.1 147.6
±
21.4 144.5
±
27.9 134.9
±
17.5 0.02*
DBP
89.8
±
13.2 90.69
±
10.8 88.2
±
11.85 86.4
±
7.6 0.361
CR: concentric remodelling, CH: concentric hypertrophy, EH: eccentric
hypertrophy, N: normal geometry, BSA: body surface area (g/m
2
), SBP:
systolic blood pressure (mmHg), DBP: diastolic blood pressure (mmHg).
*Statistically significant.
