CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 5, June 2012
AFRICA
257
velocity and E/A ratio. The diastolic period was also longer in
the OHyp subjects compared to controls.
Among the male gender, statistical differences were found
in only some echocardiographic parameters. Hypertensive vs
normotensive offspring: left atrial diameter [3.20 (0.42) vs 2.93
(0.44) cm,
p
=
0.012]; posterior wall thickness in systole [1.13
(0.26) vs 1.29 (0.21) cm,
p
=
0.008]; and deceleration time of the
E wave [180.8 (60.2) vs 152.7 (44.6) ms,
p
=
0.034].
On the other hand, among the females, statistical differences
were found in some of the physical and echocardiographic
parameters. Hypertensive vs normotensive offspring: height
[1.64 (0.08) vs 1.60 (0.05) m,
p
=
0.032]; body surface area [1.66
(0.17) vs 1.59 (0.13) m
2
,
p
=
0.040]; diastolic blood pressure
[71.1 (8.3) vs 671.(7.5) mmHg,
p
=
0.040]; mean arterial blood
pressure [84.5 (9.0) vs 80.6 (6.5) mmHg,
p
=
0.040]; duration
of the medial annulus IVRT [178.0 (55.4) vs 151.2 (54.5) ms,
p
=
0.045].
Discussion
This study shows that normotensive offspring of hypertensive
Nigerians had abnormal diastolic functional parameters compared
with normotensive control subjects without a family history of
hypertension. The changes in left ventricular filling dynamics
and an increased left ventricular mass occurred early in the
development of systemic hypertension. Increased left ventricular
mass and diastolic dysfunction have been demonstrated in the
early stages of hypertension, in the stage of prehypertension,
and in hypertensive subjects without left ventricular hypertrophy.
In this study, the offspring of hypertensive subjects showed
features of early diastolic dysfunction even in the absence
of increased left ventricular mass. This was demonstrated
by significantly higher deceleration time of E, as well as a
prolonged diastolic period, assessed by tissue Doppler. Impaired
relaxation is conventionally associated with increased A velocity,
and reduced E/A ratio. Our finding was similar to the work of
Graettinger
et al
.
16
who also demonstrated that the flow time and
the time integral of the A wave were higher in the offspring of
hypertensives, implying a shift towards late diastolic filing.
Pulmonary vein flow parameters are useful non-invasive
methods of assessment of LV diastolic function. The present
study showed prolonged duration of theA reverse flow (Ar) in the
offspring of hypertensives. Prolonged Ar duration is associated
with impaired relaxation, as well as reduced preload.
28
There
were no demonstrable changes in the loading condition, hence
the prolonged duration of Ar can only be explained by impaired
relaxation. Transmitral inflow measurements may be affected by
age, BMI, LV mass, and heart rate but all these variables were
comparable in the two groups,
29-31
and were corrected for.
Tissue Doppler imaging is a non-invasive and easily
reproducible method of assessment of left ventricular function.
The parameters are less influenced by preload changes compared
with transmitral and pulmonary vein flow measurements and
also believed to be more sensitive than the convectional Doppler
methods. Our septal myocardial tissue Doppler measurements
showed reduced Em and Em/Am ratio and increased IVRT in
the offspring of hypertensives. These findings are indicative of
TABLE 2. MEASURED ECHOCARDIOGRAPHIC
CHARACTERISTICS
Variable (cm)
Offspring of
hypertensive
parents
(
n
=
80)
Offspring of
normotensive
parents
(
n
=
62)
p
-value
Adjusted
p
-value
Aortic root diameter
2.5 (0.29)
2.5 (0.27)
0.880 0.655
Left atrial diameter
3.1 (0.43)
3.0 (0.45)
0.197 0.042*
IVSTd
0.9 (0.19)
0.9 (0.19)
0.642 0.989
IVSTs
1.3 (0.35)
1.1 (0.25)
0.017* 0.038*
PWTd
0.7 (0.18)
0.7 (0.17)
0.248 0.658
PWTs
1.1 (0.25)
1.2 (0.24)
0.100 0.108
LVIDd
4.4 (0.47)
4.3 (0.47)
0.811 0.151
LVIDs
2.8 (0.46)
2.8 (0.38)
0.919 0.844
Fractional shortening (%) 35.0 (7.60)
35.0 (5.90)
0.585 0.180
Ejection fraction (%)
64.0 (9.80)
63.0 (7.80)
0.734 0.220
Ejection time (ms)
357.0 (46.20) 375.0 (45.80) 0.042* 0.043*
Absolute LVM (g)
112.6 (31.60) 110.7 (33.90) 0.736 0.212
LVM/Ht (g/m
2.7
)
28.1 (7.33)
27.5(7.23)
0.631 0.129
RWT
0.3 (0.09)
0.3 (0.08)
0.280 0.277
LVM
=
left ventricular mass, BSA
=
body surface area, RWT
=
relative wall
thickness, Ht
=
height.
*Statistically significant. Data adjusted for age, systolic blood pressure, diastol-
ic blood pressure, body surface area and body mass index.
TABLE 3. ECHOCARDIOGRAPHIC DOPPLER INDICES OF LV
DIASTOLIC FUNCTION IN SUBJECTSAND CONTROLS
Variable
Offspring of
hypertensive
parents
(
n
=
80)
Offspring of
normotensive
parents
(
n
=
62)
p
-value
Adjusted
p
-value
Transmitral E wave (m/s)
0.7 (0.17)
0.7 (0.13) 0.938 0.809
Duration of E wave (ms) 207.3 (45.35) 228.7 (50.40) 0.009* 0.020
Deceleration time of E
wave (ms)
149.9 (38.89) 169.0 (50.08) 0.012* 0.025
A-wave velocity (m/s)
0.4 (0.13)
0.4 (0.09) 0.123 0.100
Isovolumetric relaxation
time (IVRT)
121.0 (30.82) 113.8 (23.14) 0.378 0.148
E/A ratio
1.9 (0.51)
2.1 (0.61) 0.062 0.122
Pulmonary S wave (m/s)
0.5 (0.18)
0.4 (0.17) 0.848 0.937
Pulmonary D wave (m/s)
0.3 (0.10)
0.3 (0.10) 0.740 0.655
S/D ratio
1.5 (.0.44)
1.5 (0.54) 0.820 0.965
Pulmonary A wave (m/s)
0.2 (0.09)
0.2 (0.06) 0.652 0.545
Duration A reverse wave
(ms)
113.5 (70.69) 81.7 (49.31) 0.024* 0.067
*Statistically significant. Data adjusted for age, systolic blood pressure, diastol-
ic blood pressure, body surface area and body mass index.
TABLE 4. TISSUE DOPPLER INDEXESAT THE MEDIAL (SEPTAL)
MITRALVALVEANNULUS
Variable (medial
annulus)
Offspring of
hypertensive
parents
(
n
=
80)
Offspring of
normotensive
parents
(
n
=
62)
p
-value
Adjusted
p-
value
Medial Sm (m/s)
0.1 (0.02)
0.1 (0.04)
0.970 0.940
Medial Em (m/s)
0.2 (0.05)
0.3 (1.38)
0.037* 0.348
Medial Am (m/sec)
0.1 (0.03)
0.1 (0.03)
0.844 0.882
Medial Em/Am
1.6 (0.01)
2.1 (0.01)
0.019* 0.028
Duration of Sm (ms)
210.9 (40.58) 201.6 (42.06) 0.186 0.187
Duration of Em (ms)
133.7 (28.87) 128.0 (26.05) 0.227 0.156
Duration of Am (ms)
85.4 (18.40)
85.1 (27.06) 0.954 0.860
Duration of diastolic
period (ms)
420.6 (136.89) 401.8 (139.32) 0.424 0.390
Isovolumetric relaxation
time (IVRT) (ms)
156.1 (46.74) 173.4 (47.98) 0.033* 0.031
Isovolumetric contrac-
tion time (IVCT) (ms)
115.9 (44.09) 113.5 (38.01) 0.731 0.740
