CARDIOVASCULAR JOURNAL OF AFRICA • Vol 21, No 2, March/April 2010
AFRICA
79
Cardiovascular Topics
Correlates of left ventricular mass in hypertensive
Nigerians: an echocardiographic study
OKECHUKWU S OGAH, AFOLABI E BAMGBOYE
Summary
Background:
Studies have shown that left ventricular mass,
diagnosed by echocardiography, correlated poorly with blood
pressure, even when the 24-hour ambulatory blood pres-
sure monitoring was taken into account in the analysis. This
may be partly because there are other determinants of left
ventricular mass such as age, gender, neurohormonal factors
and heredity.
Knowledge of the correlates of left ventricular mass
could help design individual and population strategies to
prevent or reverse left ventricular hypertrophy. To the best
of our knowledge, there is a paucity of such studies in native
Africans. Hence the purpose of this study was to define the
correlates of left ventricular mass in hypertensive Nigerians.
Methods:
The study was a retrospective analysis of
prospectively collected data in 285 hypertensive subjects.
Echocardiographic left ventricular mass was determined
using the standard formula. Stepwise multiple regression
analysis was used to determine the independent predictors
of left ventricular mass with a probability value to enter and
remove of
p
<
0.05.
Results:
There were 153 men (53.7%) and 132 women
(46.3%) in the study. The mean age of all subjects was 58.2
±
13.7 years. There was no significant gender difference in most
of the echocardiographic parameters. In a stepwise multiple
regression analysis, left ventricular wall tension, left ventricu-
lar wall stress, left atrial size, diastolic blood pressure, alcohol
consumption and a family history of hypertension were the
independent predictors of left ventricular mass in this popu-
lation. The optimum multivariate linear regression main
effects had an adjusted model,
r
2
of 0.945, thus explaining
about 95% of left ventricular mass variability.
Conclusion:
Mechanical or haemodynamic factors possibly
interacting with genetic and social factors are the likely deter-
minants of left ventricular mass in hypertensive Nigerians.
Therefore modulation of some of these factors pharmaco-
logically or non-pharmacologically will be of benefit in the
management of this patient population.
Keywords:
hypertension, left ventricular mass, correlates, deter-
minants, Nigeria
Submitted 22/6/09, accepted 13/8/09
Cardiovasc J Afr
2010;
21
: 79–85
Left ventricular hypertrophy (LVH) has been shown to be a
significant risk factor for adverse outcomes both in patients
with hypertension and in the general population.
1,2
Although for
many years LVH was thought to be a beneficial compensatory
mechanism for maintaining wall stress in left ventricular (LV)
pressure and volume overloads, epidemiological studies using
electrocardiography (ECG) and more recently echocardiography
(ECHO) have elucidated the profound independent risk of LVH
for congestive heart failure (CHF),
3,4
coronary artery disease
(CAD),
5,6
life-threatening arrhythmias
7
and cardiac mortality.
1-4
Studies have shown that, among other things, increased left
ventricular mass (LVM) is associated with a significant excess
of cardiovascular morbidity and mortality.
8
This is independent
of the co-existence of coronary artery disease and hypertension.
8
There is a threefold increase in the mortality rate in persons with
either of these conditions in addition to increased LVM.
8
The
risks of coronary, peripheral or cerebral vascular disease are also
raised even among normotensive individuals with LVH.
1,3,4
LVH defined by ECG has been shown to be an independent
risk factor for cardiovascular events.
4
More recently LVH defined
by echocardiography, a more sensitive diagnostic tool, has simi-
larly been shown to increase cardiac risk.
9
Recent data from the
LIFE study (Losartan Intervention For Endpoint reduction in
hypertension) revealed a close correlation between microalbu-
minuria and ECG-determined LVH.
10-12
Regression of LVH has also been shown to be possible using
either antihypertensive drugs (except hydralazine and minoxi-
dil) or non-pharmacological lifestyle modifications. Therefore
an understanding of the factors promoting increased LVM in
hypertensive Nigerians may permit the development of strate-
gies aimed primarily at preventing LVH or promoting regression
more effectively. Moreover, to the best of our knowledge, no
work of this nature has been carried out in this environment.
The objectives of the present study were to assess the non-
haemodynamic and haemodynamic correlates of LVM among
hypertensive Nigerians seen at the University College Hospital
(UCH), Ibadan, Nigeria.
Methods
The study was carried out at the Medical Outpatient Unit of the
University College Hospital, Nigeria. It was a retrospective anal-
Department of Medicine, Federal Medical Centre, Idi-Aba,
Abeokuta, Nigeria
OKECHUKWU S OGAH, MB BS, Dipl, MSc, FWACP,
Departments of Epidemiology, Medical Statistics and
Environmental Health (EMSEH), College of Medicine,
University of Ibadan, Nigeria
AFOLABI E BAMGBOYE, PhD
