Cardiovascular Journal of Africa: Vol 21 No 2 (March/April 2010) - page 21

CARDIOVASCULAR JOURNAL OF AFRICA • Vol 21, No 2, March/April 2010 AFRICA 83
0.195). LV mass was also positively related with body surface
area (r = 0.228), systolic BP (r = 0.200) diastolic BP (r = 0.235)
and mean arterial BP (r = 0. 239). Serum creatinine (r = 0.225),
serum uric acid (r = 0.362), aortic root diameter ( r = 0.238), left
atrial diameter (r = 0.514), LV end-diastolic volume (r = 0.727)
and LV end-systolic volume (r = 0.989) were all positively and
directly related to LV mass.
All the haemodynamic parameters also showed a relationship
with LV mass. The relationship was mostly positive except for
fractional shortening (r = –0.380), ejection fraction (r = –0.415),
total peripheral resistance (r = –0.329) and pulse pressure/stroke
volume ratio (r = –0.284), which showed a negative relationship
with LV mass. LVM was not significantly related to indices of
LV diastolic function. However the relationship with A-velocity
and deceleration time was negative
In a stepwise multivariate linear regression analysis, the
independent predictors of LV mass were LV wall tension, left
atrial diameter, LV wall stress, LV end-diastolic volume, diasto-
lic blood pressure, family history of hypertension, and alcohol
consumption. These variables explained about 95% of the vari-
ability in LV mass (Table 6). A sub-analysis of the newly present-
ing hypertensive subjects did not yield additional or different
information.
Discussion
Left ventricular mass is a powerful and independent risk factor
for cardiovascular events. In this study, the prevalence of
echocardiographically defined LVH in subjects aged 20 to 94
years was 38.9%. Previous studies have reported prevalences
ranging from 15 to 64%.24-26
In a study of 50 untreated hypertensive and 50 normotensive
subjects, Ganau et al. 27,28 showed that systolic BP, stroke–volume
index and end-systolic stress/volume index ratio were strong
determinants of indexed LVM. Another study by Jones and
colleagues29 also observed that changes in haemodynamic load
may induce LVH and abnormal LV remodelling in hyperten-
sion.
These parameters were determined in the present study, where
it was found that LVM correlated with end-diastolic volume,
end-systolic volume, stroke volume, stroke index, cardiac output
and cardiac index. LVM was also found in this study to be related
to total peripheral resistance, pulse pressure/stroke volume ratio,
LV wall tension and LV wall stress.
Dahan and colleagues30 reported LV end-diastolic volume
and end-systolic meridional stress-to-volume ratio as the main
determinants of LVM in a population of patients on haemodi-
alysis. A recent comprehensive report by Chen and co-workers31
TABLE 5. CORRELATION OF LV MASSWITH
CLINICAL, BIOCHEMICALAND OTHER
ECHOCARDIOGRAPHICVARIABLES IN 285
HYPERTENSIVE SUBJECTS SEENAT UCH, IBADAN
Parameter r r2 p -value
Age (years) 0.061 0.004 0.302
Gender (male vs female)* 0.091 0.008 0.124
Duration (years) 0.123 0.015 0.046
Alcohol consumption (yes/no)* 0.209 0.044 0.0004
Cigarette smoking (yes/no)* 0.190 0.36 0.0012
Family history of hypertension (yes/no)* 0.074 0.005 0.214
Diabetes mellitus (yes/no)* 0.139 0.019 0.0185
Weight (kg) 0.187 0.035 0.0016
Height (cm) 0.195 0.038 0.0010
Body mass index (kg/m2 ) 0.065 0.004 0.280
Body surface area (m 2) 0.228 0.052 0.001
Systolic blood pressure (mmHg) 0.200 0.040 0.0007
Diastolic blood pressure (mmHg) 0.235 0.050 < 0.0001
Pulse pressure (mmHg) 0.076 0.006 0.203
Mean arterial pressure (mmHg) 0.239 0.057 < 0.0001
Sodium (mmol/l) 0.017 0.0002 0.831
Potassium (mmol/l) –0.123 0.015 0.118
Creatinine (mg/dl) 0.225 0.051 0.002
Uric acid (mg/dl) 0.362 0.131 0.0002
Fasting blood glucose (mg/dl) 0.071 0.005 0.420
2-hour postprandial glucose (mg/dl) 0.046 0.002 0.658
Total cholesterol (mg/dl) 0.121 0.015 0.189
Triglycerides (mg/dl) –0.013 0.0001 0.886
High-density lipoprotein (mg/dl) –0.063 0.004 0.516
Low-density lipoprotein (mg/dl) 0.109 0.012 0.268
Heart rate (beats/min) 0.092 0.009 0.123
Aortic root diameter (cm) 0.238 0.056 < 0.0001
Left atrial diameter (cm) 0.514 0.264 < 0.0001
Septal wall thickness (cm) 0.588 0.346 < 0.0001
LV posterior wall thickness (cm) 0.426 0.182 < 0.0001
LV end-diastolic diameter (cm) 0.718 0.516 < 0.0001
LV end-systolic diameter (cm) 0.694 0.482 < 0.0001
Relative wall thickness (cm) –0.126 0.016 0.034
Fractional shortening (%) –0.380 0.144 < 0.0001
Ejection fraction (%) –0.415 0.172 < 0.0001
End-diastolic volume (ml) 0.727 0.528 < 0.0001
End-systolic volume (ml) 0.989 0.471 < 0.0001
Stroke volume (ml) 0.518 0.269 < 0.0001
Stroke index (ml/m 2) 0.228 0.052 0.0001
Cardiac output (ml) 0.458 0.210 < 0.0001
Cardiac index (ml/m2) 0.414 0.171 < 0.0001
Total peripheral resistance –0.329 0.108 < 0.0001
Pulse pressure–stroke volume ratio –0.284 0.018 < 0.0001
Wall stress (dynes/cm2) 0.670 0.449 < 0.0001
Wall tension 0.255 0.065 < 0.005
Mitral early velocity (E) 0.089 0.008 0.168
Mitral late velocity(A) –0.050 0.002 0.443
E/A ratio 0.110 0.012 0.090
Deceleration time –0.072 0.005 0.279
*Values were entered as dummy variables.
TABLE 6. INDEPENDENT PREDICTORS OF LV MASS IN
HYPERTENSIVE SUBJECTS SEENAT UCH, IBADAN
Variable b SE Beta p -value
Wall tension 0.277 0.0 0.324 0.000
Left atrial diameter 17.55 5.74 0.131 0.004
Wall stress –0.794 0.067 –0.691 0.000
LV end-diastolic volume 1.465 0.118 0.941 0.000
Diastolic BP 0.557 0.215 0.122 0.012
Family history of hypertension 18.10 7.87 0.082 0.026
r2 = 0.952 (adjusted 0.945), F = 138.77, p = 0.000.