The LA size was similar in both subjects and controls, 3.41 + 0.73cm and 3.37 0.51cm, p = 0.47 (Table 7). There were no significant gender or age differences in both groups. (Tables 8 & 9) (ii) Aortic root (Ao) size
The aortic root size was comparable in both subjects and controls, 2.91 + 0.56cm and 2.85 + 0.47cm, p=0.53 (Table 7). There were no significant gender or age differences in the mean values of the Ao size (Tables 8 & 9).
(iii) Right Ventricular Outflow Tract (RVOT)
For the subjects and controls mean RVOT were 2.93 0.96cm vs 2.91 + 0.87cm respectively, which were comparable p = 0.77 (Table 7). There were no significant age or gender differences in the mean RVOT for both subjects and controls. (Table 8 & 9).
Table 7:
ECHOCARDIOGRAPHIC PARAMETERS OF SUBJECTS AND CONTROLS
Parameter Subjects
Mean +SD (n = 91)
Controls Mean +SD
(n = 92)
p-value
LA (cm) 3.41 0.73 3.37 0.51 0.51
Ao (cm) 2.91 0.56 2.85 0.47 0.53
RVOT (cm) 2.93 0.96 2.91 0.87 0.77
IVS (cm) 1.13 0.12 0.99 0.09 0.00001
PW (cm) 0.95 0.12 0.89 0.09 <0.001
LVDD (cm) 4.29 0.32 4.21 0.27 0.20
LVDS (cm) 2.93 0.43 2.89 0.51 0.59
LVM (g) 179.10 40.67 147.70 30.98 0.000001
LVMI (g/m2) 106.97 18.49 87.95 16.54 0.000001
LVM/Ht2.7 (g/m2.7) 44.86 8.75 36.36 7.13 0.000001
RWT 0.44 0.06 0.42 0.04 0.05
Pul vel (cm/sec) 89.19 3.84 86.85 4.63 0.41
Aortic vel (cm/sec) 111.38 6.16 108.31 5.73 0.53
Legend:
LA = Left Atrium; Ao= Aortic Root; RVOT= Right Ventricular Outflow Tract; IVS = Interventricular Septum; PWT
= Posterior Wall Thickness; LVDD = Left Ventricular Diameter in Diastole; LVDS = Left Ventricular Diameter in Systole; LVM = Left Ventricular Mass; LVMI = Left Ventricular Mass Index; LVM/Ht2.7 = Left Ventricular Mass Indexed to Height2.7; RWT = Relative Wall Thickness; Pul vel = Pulmonary Velocity; Aortic Vel = Aortic Velocity;
Table 8:
GENDER DISTRIBUTION OF ECHOCARDIOGRAPHIC VARIABLES
Subjects (mean + S.D) Controls (mean + S.D)
Variables Males (n = 46)
Females (n = 45)
p – value Males (n = 50)
Females (n = 42)
p -value
LA(cm) 3.41 0.61 3.39 0.57 0.59 3.33 0.59 3.29 0.15 0.47
Ao (cm) 2.88 0.41 2.80 0.39 0.31 2.81 0.44 2.77 0.38 0.29 RVOT(cm) 3.10 0.76 2.95 0.88 0.71 2.99 0.37 2.97 0.49 0.37
IVS(cm) 1.17 0.11 1.10 0.12 0.24 1.00 0.09 0.97 0.09 0.11
PWT(cm) 0.96 0.11 0.93 0.14 0.60 0.91 0.09 0.87 0.08 0.28
LVDD(cm) 4.41 0.31 4.18 0.27 <0.005 4.27 0.30 4.14 0.22 0.09 LVDS(cm) 2.91 0.33 2.86 0.44 0.43 2.86 0.51 2.83 0.49 0.46 LVM (g) 194.02 36.79 163.81 39.12 <0.001 155.97 34.95 137.6521.86 <0.001 LVMI (g/m2) 112.74 13.23 101.06 21.24 <0.005 91.22 16.83 83.96 15.49 <0.05 LVM/Ht(g/m2.7) 46.08 7.11 43.62 10.00 0.21 37.06 7.67 35.50 6.42 0.33
RWT 0.44 0.06 0.45 0.08 0.54 0.43 0.04 0.42 0.05 0.26
Aortic vel 100.39 5.37 111.41 6.01 0.79 108.56 4.98 109.16 5.99 0.51 Pul vel 88.71 4.11 87.91 4.10 0.89 87.76 4.30 86.51 4.01 0.69
Legend:
LA =Left Atrium; Ao = Aortic Root; RVOT = Right Ventricular Outflow Tract; IVS = Interventricular Septum; PWT = Posterior Wall Thickness; LVDD = Left Ventricular Diameter in Diastole; LVDS = Left Ventricular Diameter in Systole; LVM = Left Ventricular Mass; LVMI = Left Ventricular Mass Index; LVM/Ht2.7 = Left Ventricular
Mass Indexed to Height2.7; RWT = Relative Wall Thickness; Pulmonary Velocity;
Aortic Vel = Aortic Velocity.
Table 9:
AGE DISTRIBUTION OF ECHOCARDIOGRAPHIC PARAMETERS
Variables Subjects (mean + S.D) Controls (mean +S.D)
A (n = 42)
B (n = 49)
p-value A
(n = 39)
B (n = 53)
p-value
LA (cm) 3.31 0.51 3.44 0.63 0.45 3.26 0.44 3.39 0.71 0.59
Ao (cm) 2.88 0.51 2.91 0.66 0.44 2.71 0.37 2.89 0.49 0.41
RVOT(cm) 2.88 0.43 2.97 0.64 0.46 2.91 0.46 2.97 0.59 0.61 IVS (cm) 1.10 0.12 1.16 0.11 <0.05 0.96 0.09 1.01 0.09 <0.005 PWT (cm) 0.90 + 0.13 0.98 0.11 <0.05 0.86 0.09 0.91 0.08 <0.0001 LVDD (cm) 4.41 0.32 4.41 0.32 <0.0001 4.30 0.28 4.08 0.21 <0.0001 LVDS (cm) 2.76 0.31 2.94 0.51 0.38 2.71 0.49 2.91 0.61 0.34 LVM (g) 163.19 38.57 192.48 37.82 <0.0001 131.81 24.46 158.96 30.35 <0.0001 LVMI (g/m2) 100.65 18.15 112.28 17.24 <0.005 80.19 13.71 93.45 16.28 <0.001 LVM/Ht(g/m27) 41.68 8.25 47.54 8.33 0.005 33.44 5.16 38.43 7.64 <0.01
RWT 0.45 0.06 0.44 0.06 0.35 0.42 0.04 0.43 0.04 0.54
Pul vel (cm/sec) 89.91 4.01 88.17 3.98 0.71 90.04 3.59 88.741 2.61 0.69 Aortic vel
(cm/sec)
113.07 5.96 109.91 5.47 0.53 100.40 5.02 109.14 6.01 0.74
Legend
A = 13 – 15 year age group B = 16 – 19 year age group
Legend:
LA =Left Atrium; Ao = Aortic Root; RVOT = Right Ventricular Outflow Tract; IVS = Interventricular Septum; PWT = Posterior Wall Thickness; LVDD = Left Ventricular Diameter in Diastole; LVDS = Left Ventricular Diameter in Systole; LVM = Left Ventricular Mass; LVMI = Left Ventricular Mass Index; LVM/Ht2.7 = Left Ventricular
Mass Indexed to Height2.7; RWT = Relative Wall Thickness; Pul vel = Pulmonary Velocity; Aortic Vel = Aortic Velocity.
(iv) Interventricular Septum (IVS)
The subjects had significantly thicker IVS than the controls, 1.13 0.12cm vs 0.99 0.09cm, p = 0.00001. (Table 7). Twenty-four of the subjects and 3 of the controls had abnormally thickened IVS.
The mean IVS was comparable in males and females in both subjects and controls, 1.17 0.11cm and 1.10 0.12cm for male and female subjects, p=0.24 and 1.00 0.9cm and 0.97 0.09cm for male and female controls, p = 0.11. (Table 8)
Subjects within the 16 -19 year age group had a significantly higher mean IVS than those in the 13-15 age group, 1.16 0.11cm and 1.10 0.12cm, p<0.05. Similarly in the controls those in the older age group had significantly higher mean IVS, 1.01 0.09cm vs 0.96
0.09cm, p<0.005. (Table 9)
(v) Posterior Wall Thickness (PWT)
Amongst the subjects the mean PWT differed significantly from that of the controls, 0.95 0.12cm and 0.89 0.09cm, p<0.001. (Table
7). Only 3% of the subjects had abnormally thickened PW while none of the controls had abnormally thickened PW.
Mean PWT values for males and females were comparable in both subjects and controls. (Table 8).
In the subjects mean PWT in the 16-19 year age group was significantly higher than those in the 13 -15 year age group, 0.98 0.11cm vs 0.90 0.13cm, p<0.05. Amongst the controls also those in the older age group had significantly higher PWT than those in the lower age group, 0.91 0.08cm vs 0.86 0.09cm, p<0.0001.
(Table 9).
(vi) Left Ventricular Dimension in diastole (LVDD)
There was no significant difference in the mean LVDD of both subjects and controls, 4.29 0.32cm vs 4.12 0.27cm, p = 0.20.
None of the subjects or controls had an abnormal LVDD. (Table 7).
Males had significantly higher mean LVDD value than females amongst the subjects, 4.41 0.31cm vs 4.18 0.27cm p<0.005.
Amongst the control the mean LVDD values between males and females were comparable, 4.27 0.30cm vs 4.14 0.22cm, p = 0.09. (Table 8).
The mean LVDD of subjects within the 16 -19 year age group was significantly higher than those in the 13 -19 year age group, 4.41 0.32cm vs 4.16 0.25cm, p<0.0001. Similar finding was observed
amongst the controls, 4.30 0.28cm vs 4.08 0.21cm, p< 0.0001.
(Table 9).
(vii) Left Ventricular Dimension in Systole (LVDS)
The mean values for both subjects and controls were comparable 2.93 0.43cm and 2.89 0.51cm p = 0.59. (Table 7).
There were no significant gender or age differences in the mean value of the LVDS. (Tables 8 & 9).
(viii) Left Ventricular Mass (LVM)
The mean LVM value of the subjects was significantly higher than that of the controls, 179.10 40.67g vs 147.70 30.98g, p<0.000001. (Table 7).
Males had a significantly higher mean LVM than females in both groups. Amongst the subjects mean LVM was 194.02 36.79g and 163.81 39.12g for males and females respectively, p<0.001. In the controls mean LVM were 155.97 34.95g and 137.65 21.86g for males and females respectively p<0.001. (Table 8).
Subjects in the 16 –19 year age group had significantly higher mean LVM than those in the 13-15 year age group, 192.48 37.82g vs 163.19 38.57g, p<0.0001. Similarly in the controls themean LVM ofindividuals in the 16 -19 year age group were significantly higher than those in the 13 -15 year age group, 158.96 30.35g, vs 131.81 24.46g, p<0.0001. (Table 9).
Subjects with maternal hypertension alone had the highest mean LVM, which differed significantly from the mean value of subjects
31.75g, p<0.001. It was however comparable with the mean LVM value in subjects in whom both parents were hypertensive, 187.46
38.19g vs 183.96 36.41g, p<0.68. The mean LVM of subjects in whom both parents were hypertensive was significantly higher than the value in subjects with paternal hypertension alone, 183.96 36.41 g vs 173.93 31.75g, p< 0.001.
(xiiia) Correlates of LVM
LVM had the best correlation with BSA followed by weight, height and age in both subjects and controls. It had moderate correlation with SBP. Its correlation with DBP and male gender though weak was statistically significant. Although LVM had positive correlation with BMI it was not statistically significant. It’s correlation with female gender was the weakest. (Table 10)
(xiiib) Multiple Regression Analyses
This was used to determine the independence of the variable that explains the variance of LVM. The stepwise linear regression is presented in (Table 11). Each of the correlation coefficient was positive, indicating that increasing age, weight and SBP are all
associated with increasing LVM in the subjects. Male gender, height, BSA and DBP were found not to be significant correlates of LVM in this regression model. A similar pattern was observed amongst the controls. However, SBP, which was a significant correlate of LVM in the subjects, was not found to be significant amongst the controls.
Logistic regression further showed that in the subjects weight accounted for most of the variance in LVM followed by age.
Although SBP was a statistically significant correlate of LVM, it only accounted for a small portion of the variance in LVM. In the controls, age accounted for most of the variance in LVM followed by weight.
SBP was not found to contribute to the variance in LVM. (Table 12)
Table 10:
Pearson’s Correlation Coefficients Between LVM And Various Independent Variable (Subjects And Controls)
Subjects Controls
Variable Pearson’s
Correlation Coefficient
p-value Pearson’s Correlation Coefficient
p-value
Age 0.81 <0.001 0.89 <0.001
Male gender 0.31 0.03 0.37 0.01
Female gender 0.11 0.07 0.27 0.07
Weight 0.87 <0.001 0.82 <0.0001
Height 0.73 <0.001 0.67 <0.001
BMI 0.28 0.10 0.36 0.16
BSA 0.79 <0.0001 0.84 <0.0001
SBP 0.61 <0.0001 0.42 <0.0001
DBP 0.41 <0.001 0.33 <0.0001
Legend:
BMI = Body Mass Index BSA = Body Surface Area
SBP = Systolic Blood Pressure
Table 11:
Stepwise Multiple Linear Regression (Subjects And Controls)
Subjects Controls
Variable Partial r p – value Partial r p-value Age 0.53 <0.001 0.61 <0.0001
Male gender 0.04 0.09 0.06 0.09
Weight 1.63 <0.0001 1.22 <0.001
Height 0.03 0.09 0.06 0.09
BSA 0.27 0.09 0.37 0.08
SBP 0.56 <0.001 0.34 0.011
DBP 0.03 0.84 0.09 0.22
Dependable variable: LVM Legend
BSA = Body Surface Area
SBP = Systolic Blood Pressure DBP = Diastolic Blood Pressure
Table 12:
Logistic Regression for age, weight and SBP (subject and controls)
Subjects Controls
Variable R2 p – value R2 p – value
Age 0.25 0.001 0.47 0.0001
Weight 0.65 0.001 0.49 0.01
SBP 0.10 0.01 0.04 0.75
Dependable variable: LVM Legend
SBP = Systolic Blood Pressure
(ix) Left Ventricular Mass Index (LVMI)
The mean LVMI of the subjects was significantly higher than that of the controls, 106.97 18.49g/m2 vs 87.95 16.54g/m2, p<0.000001.
(Table 7).
Males had a significantly higher mean LVMI than females, 112.74
13.23g/m2 vs 101.06 21.24g/m2, p<0.005 for the subjects and 91.22 16.83g/m2 vs 83.96 15.49g/m2, p<0.05 for controls.
(Table 8).
The mean LVMI for subjects within the 16 -19 year age group was significantly higher than those in the 13 -15 year age group, 112.28
17.24g/m2 vs 100.65 18.15g/m2, p<0.005. Similarly amongst the controls those within the 16 -19 year age group had a significantly higher mean LVMI than those in the 13-15 year group, 93.45 16.28g/m2 vs 80.19 13.71g/m2, p<0.005. (Table 9).
Subjects from hypertensive mothers had the highest mean LVMI, which differed significantly from those from hypertensive fathers, 110.15 20.53 g/m2 vs 104.31 17.54g/m2, p<0.001. The difference in the mean LVMI between subjects from hypertensive mothers alone and those in whom both parents were hypertensive was not significant, 110.15 20.53g/m2 vs 108.14 18.21g/m2, p = 0.38.
Individuals with larger LVMI had SBP and to a lesser extent DBP in the upper quartiles of the blood pressure distribution curve (Tables 13 & 14).
Table 13:
Relationship Between LVMI (g/m2) and SBP (Subjects and Controls)
SBP Subjects
Controls p- value
(Mean SD) (n = 91)
(Mean SD) (n = 92)
Q1 98.62 15.18 (n = 31)
82.72 18.78 (n = 25)
0.26
Q2 104.63 19.52 (n = 16)
88.90 13.41 (n = 36)
0.0001
Q3 105.16 14.60 (n = 28)
93.23 20.12 (n = 15)
0.005
Q4 124.21 16.69 (n = 16)
96.56 16.28 (n = 16)
0.0001
Legend:
SBP = Systolic Blood Pressure
LVMI = Left Ventricular Mass Index
Q1 = 25% of Systolic Blood Pressure distribution curve Q2 = 50% of Systolic Blood Pressure distribution curve Q3 = 75% of Systolic Blood Pressure distribution curve
Q4 = 100% of Systolic Blood Pressure distribution curve Table 14:
Relatio nship Between LVMI (g/m2)
and DBP (Subjects
and Controls)
DBP Subjects
C o n t r o l s p-value
(Mean SD) (n = 91)
(Mean SD) (n = 92)
Q1 103.64 + 15.90 (n = 25)
87.23 19.80 (n = 25)
0.0004
Q2 100.46 + 18.07
(n = 29)
86.67 9.90 (n =25)
0.003
Q3 106.34 16.04
(n = 19)
88.90 21.30 (n =20)
0.0001
Q4 101.65 18.90
(n = 27)
86.86 13.47 (n = 22)
0.0001
Legend:
DBP = Diastolic Blood Pressure
LVMI = Left Ventricular Mass Index
Q1 = 25% of Diastolic Blood Pressure distribution curve Q2 = 50% of Diastolic Blood Pressure distribution curve Q3 = 75% of Diastolic Blood Pressure distribution curve Q4 = 100% of Diastolic Blood Pressure distribution curve
(x) LVM/Ht2.7
The mean LVM indexed to Ht2.7 in g/m2 was significantly higher in the subjects than in the controls, 44.86 8.75g/m2.7 vs 36.36 7.13g/m2.7, p< 0.000001. (Table 7)
Males had similar mean values than females, 46.08 7.11g/m2.7 vs 43.62 10.10 g/m2.7, p = 0.21 for the subjects and 37.06 7.67g/m2.7 vs 35.50 6.42g/m2.7, p = 0.33 for the controls. (Table 8).
Among the subjects the mean LVM/Ht2.7 was significantly higher in the 16 -19 year age group than in the 13 -15 year age group, 47.54
8.33g/m2.7 vs 41.68 8.25g/m2.7, p = 0.005. In the control a similar pattern was observed 38.43 7.64g/m2.7 vs 33.44 5.16g/m2.7, p < 0.01. (Table 9).
Amongst the subjects, those with hypertensive mothers had the highest value, followed by those in whom both parents were hypertensive and least by those with hypertensive fathers, 46.48 8.60g/m2.7, 45.01 9.69g/m2.7 and 44.29 7.80g/m2.7 respectively.
However there were no significant differences amongst the 3 sub-groups, p = 0.76, 0.63 and 0.48 respectively.
(xi) Relative Wall Thickness (RWT)
There was a significant difference between the mean RWT of both subjects and controls, 0.44 0.06 and 0.42 0.04, p<0.05 (Table
7). Thirty-six (39.6%) of the subjects and 7(7.6%) of the controls had abnormally thickened RWT i.e. RWT >0.45, p<0.0001.
There was no significant age or gender differences in the mean RWT in both subjects and controls. (Tables 8 & 9).
(xii) Left Ventricular Geometry
Fifty (54.9%) of the subjects had normal geometry, 29 (31.9%) had concentric remodeling, 7 (7.7%) had concentric hypertrophy while 5 (5.5%) had eccentric hypertrophy. In the controls 78 (84.8%) had normal geometry, 11 (11.9%) had concentric remodeling, 3 (3.3%) had eccentric hypertrophy while there was no case of concentric hypertrophy (Figure 3).
0%
10%
20%
30%
40%
50%
60%
70%
80%
Normal Geometry
Concentric Remodeling
Eccentric Hypertrophy
Concentric Hypertrophy
Figure 3: Pattern of Left Ventricular Geometry of Subjects and Controls
Subject Control
The gender and age distribution of the left ventricular geometry for subjects and controls are shown in Tables 15 and 16.
Table 15:
Gender Distribution of LV Geometry
Type of LV Geometry Subjects Controls
Males (n = 46)
n (%)
Females (n = 45)
n (%)
p-value Males (n = 50)
n (%)
Females (n = 42)
n (%)
p-value
Normal Geometry Concentric Remodeling Concentric Hypertrophy Eccentric Hypertrophy
24 (48) 15 (51.7)
5 (71.4) 4 (80)
26 (50) 14 (48.3)
2 (28.6) 1 (20)
0.68 0.44
<0.0001
<0.001
40 (51.3) 8 (72.7)
- 3 (100)
38 (48.8) 3 (27.3)
- -
<0.01
<0.01
<0.0001
<0.00001
Table 16:
Age Distribution of LV Geometry
Type of LV Geometry Subjects Controls
A (n = 42)
n (%)
B (n = 49)
n (%)
p-value A
(n = 39) n (%)
B (n = 53)
n (%)
p-value
Normal Geometry Concentric Remodeling Concentric Hypertrophy Eccentric Hypertrophy
23 (46.0) 10 (34.5) 1 (14.3)
-
27 (54.0) 19 (65.5) 6 (85.7)
5 (100)
<0.001
<0.0001
<0.00001
<0.0000001
30 (38.5) 1 (9.9)
- -
48 (61.5) 10 (90.1)
- 3 (100)
<0.001
<0.0001 -
<0.000001
Legend:
A = 13 – 15 year age group B = 16 – 19 year age group
(xiii) Aortic Velocity
There was no significant difference between the mean values of both the subjects and controls, 111.38 6.16 cm/sec and 108.31 5.73cm/sec, p = 0.53 (Table 7). There were no abnormally high velocities. There was no significant gender and age-related differences in the mean aortic velocities for both subjects and controls (Tables 8 & 9).
(xiv) Pulmonary Velocity
There was no significant difference between the mean values of both the subjects and controls, 89.19 3.84cm/sec and86.85 4.63cm/sec, p = 0.41 (Table 7). All values were within the normal range and there was no significant gender or age related
differences in the mean pulmonary velocity values for both subjects and controls (Tables 8 & 9).