CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 5, June 2012
258
AFRICA
diastolic dysfunction and were similar to those of Aeschbacher
et al.
32
in their prospective study of the offspring of hypertensive
subjects, particularly offspring who became hypertensive after
five years of follow up.
In an earlier study by the same group,
33
on offspring of
hypertensives, there was no evidence of diastolic dysfunction
using conventional Doppler methods. At follow up, pulmonary
vein flow and myocardial tissue imaging were added and despite
comparable blood pressure and left ventricular masses, the
diastolic dysfunction became more evident. Our study confirms
that if sensitive methods of assessing diastolic function are
employed, deterioration in diastolic function can be demonstrated
in normotensive subjects with a parental history of hypertension.
This further confirms the hypothesis that abnormalities of
cardiac function may predate clinical hypertension in genetically
predisposed individuals.
Studies that did not demonstrate differences between diastolic
function in the offspring of hypertensives and normotensives
used only mitral inflow parameters, which are inadequate in
assessing diastolic function, as the parameters are easily affected
by loading conditions.
13,14
Our study had the advantage of
assessing diastolic function in offspring of hypertensives using
conventional Doppler parameters as well as myocardial tissue
Doppler imaging.
Our data suggest that diastolic dysfunction was present in
offspring of hypertensive subjects despite the fact that they had
similar baseline characteristics and left ventricular dimensions
to the control group. Although the effect of the insignificantly
higher blood pressure and LVM on the findings of diastolic
function cannot be totally ruled out, our findings are similar
to those of Aeschbacher
et al
,
33
who also corrected for these
variables in the analysis.
Gender differences noted in the analysis are not surprising.
Other workers have reported gender differences in LV parameters,
as well as parameters of LV diastolic function.
33-36
In a study of
121 normotensive youths, Kapuku
et al
.
36
noted that females
had a higher relative wall thickness, lower E/A ratio and shorter
IVRT than males.
Before changes in LV mass or hypertension become apparent,
various changes occur at the cellular level that cause alterations
in the myocardial architecture and collagen structure. Metabolic
and neuro-endocrine changes also occur. Some studies have
demonstrated acceleration of these factors in the offspring of
hypertensives.
The study had some limitations. We did not obtain information
on and correct for factors such as socio-economic status, level of
physical activity, diet or biochemical parameters, and this may
have affected the results.
Conclusion
Diastolic dysfunction has been shown to affect the quality of
life of patients with advanced cardiac disease. Assessment of
diastolic function is of paramount importance in the management
of this disease. Early identification of subjects with or at risk for
hypertension and diastolic dysfunction may help to stratify risk,
guide therapy and prevent target-organ damage in these patients.
The consistent independent effects of increased body weight
and particularly male gender
37,38
on the development of increased
left ventricular mass reaffirms the need for early intervention
with the institution of lifestyle modification in these subjects.
Lifestyle modifications have been shown to reduce blood pressure
in hypertensive patients. These interventions may prevent or
delay the development of hypertension in normotensive subjects
in the long term. Longitudinal studies are needed to determine
the prognosis of these changes in normotensive offspring of
hypertensive parents.
We acknowledge the contribution and assistance of the ECG/ECHO unit
team of Ms Ogunrinde, Adegbola, Adubi, Babatunde and Akinwale of
University College Hospital, Ibadan. We are also grateful to Drs Ajit
Mullasari and Ezhilan of Madras Medical Mission, Chennai, India, who read
the manuscript and offered useful suggestions.
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