Cardiovascular Journal of Africa: Vol 29 No 2 (March/April 2018)

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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 2, March/April 2018 86 AFRICA
diameters.19 On the other hand, Zoppini et al. showed a possible
65% LA enlargement (defined as indexed Vmax ≥ 34 ml/m2) for
each 10 years’ duration of diabetes.14 On the basis of these
findings, we speculate that although diabetes was an independent
predictor of LA volume in univariate analysis, in multivariate
analysis, age and BMI were the independent predictors of LA
volume in the early stages of diabetes.
LA function is evaluated and indexed to BSA by calculating
PEV, AEV, TEV and PEF, AEF and TEF from Vmax, Vmin and
Volp. TEV describes the reservoir, PEV describes the conduit, and
AEV describes the pump function of the left atrium. Contrary
to current knowledge, Vmin increases, even in mild LV diastolic
dysfunction, whereas Vmax increases in the later stages, suggesting
that Vmin may be a more sensitive marker of LV diastolic
dysfunction. Moreover, this finding underlines the importance
of evaluation of LA function.22
Based on current knowledge, LA reservoir function
is associated with worsening LV diastolic function.7 Graca
et al. showed that LA reservoir and conduit function were
reduced in asymptomatic DM2 patients.23 The same study also
demonstrated that DM2 was independently associated with LA
reservoir function, but not with conduit function.23
Mondillo et al. investigated only diabetic patients with
normal LA size and did not find any difference in conduit
and pump function. However, they showed LA deformation
was impaired in diabetics even if LA volumes were similar
between the groups.24 Murakana et al. showed decreased LA
reservoir and conduit functions in patients with DM2 even in
the absence of LA dilatation.5 Huang et al. demonstrated, with
2D echocardiographic evaluation, increased reservoir and pump
function and reduced conduit function in patients with DM2.6
Recently, Atas et al. reported depressed reservoir and pump
function with similar conduit function in patients with DM2
compared to the control group.8
In our study, in accordance with the study of Huang et al.,
we found reduced conduit, and increased pump and reservoir
function in diabetic patients compared with the controls. The
possibly inconsistent results with previous studies may have
been due to different cardiovascular imaging techiques used for
the determination of LA function, small sample sizes, different
baseline characteristics, and different diabetes durations of the
study populations.
There are some limitations to our study. As this was a cross-
sectional study, follow up of the patients for clinical endpoints
such as AF and heart failure could not be done. Therefore,
our study results cannot be used to direct standard clinical
care. Moreover, as the population size was relatively small, our
study does not permit any causal inferences and analysis on
the effect of medications on LA volume and function. For this
reason, long‑term follow up and large‑scale prospective studies
are needed to determine the clinical predictive value of early
LA functional impairment in this population. Evaluation of
LA volume and function with 2D echocardiography was an
additional limitation of our study.
Conclusion
The results of our study showed impaired LA function may
be present in patients with DM2 with a disease duration of
a maximum of six months. BMI and increased age caused
LA enlargement and LA volumes that were independent of
the effects of hypertension and DM2. Further studies with
larger sample sizes are needed to better define the underlying
mechanisms.
The authors thank Arzu Baygul from MedStats Consulting and Prof Sule
Oktay, MD, PhD from Kappa Consulting, Traning and Limited Research Ltd
for statistical analysis and interpretation of the results.
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