23 / 84
CARDIOVASCULAR JOURNAL OF AFRICA • Volume 29, No 2, March/April 2018
AFRICA
85
with DM2 who was diagnosed in the preceding six months, and
this finding was mainly due to BMI and age.
Recent studies have shown that LA enlargement, obtained
from 2D echocardiography, is a good predictor of cardiovascular
outcomes.
7
However, there are several limitations to estimating
LA size because of the irregular geometry of the left atrium.
Additionally, the left atrium often enlarges asymmetrically,
which causes underestimation of its size. Therefore, it has been
suggested that LA volume may be a superior measure of LA
size.
7
Moreover, changes in LA volume are increasingly becoming
a parameter of interest as a marker of overall cardiac function.
Several studies have shown that changes in LA size and
mechanical function may be associated with adverse clinical
events such as atrial fibrillation, stroke, diastolic dysfunction and
LV failure, both in the general and the diabetic population.
6,8,10-14,19,20
Moreover, it has been reported that indexed V
max
≥
32 ml/m
2
predicts cardiovascular mortality and morbidity independently
of myocardial perfusion sintigraphy-detected myocardial
ischaemia with a six-year follow-up period.
21
Cardiovascular imaging modalities for the determination of
LA function, such as computed tomography (CT), CMRI, 2D and
3D echocardiography, are evolving. Although the main advantage
of CMRI and CT over echocardiography is the determination of
all parts of the left atrium, including the LA appendage, the use
of iodine and radiation during CT and the usefulness of CMRI
in patients with pacemakers limit their usage.
7
Therefore, we
preferred to use 2D echocardiography, which is a non-invasive,
easy-to-use and accessible method to evaluate LA volume and
function. Moreover, similar to our findings, the mean indexed V
max
value was 23.6
±
5.8 ml/m
2
in a newly diagnosed diabetes group in
the study population of Zoppini.
14
The incidence of diastolic dysfunction in patients with DM2
is reported to be 43 to 75%.
4
Recent evidence suggests that
LA dilatation and dysfunction may be a co-existing marker of
diastolic dysfunction in patients with DM2.
4
However, Kadappu
et al.
demonstrated LA dilatation may be present in patients
with DM2 independent of diastolic dysfunction and associated
hypertension.
4
Recently, another study by Zoppini
et al
. reported
that diabetes itself might cause LA enlargement.
14
These findings
suggest that co-existing diabetic atrial cardiomyopathy may
independently alter the LA size and function.
4,14
In our study, 51.8% of the diabetic patients had some degree
of diastolic dysfunction with no difference regarding LA volume
and function, compared with the diabetic patients without
diastolic dysfunction. This finding and a weak correlation
between 2D echocardiographic diastolic parameters and LA
volume in our study may have been due to the duration of
DM2, normal LV filling pressures determined by E/E
′
ratio, and
normal LV mass.
We demonstrated that increasing age and BMI had a
significant effect on LA volume. The main difference of our
study from previous ones was the duration of DM2, which was
strongy and positively associated with larger LA diameter and
impaired LA function. CARDIA investigators showed a 20-year
follow-up period of diabetes was associated with indexed LA
Table 5. Correlation analysis of LA volume and function with
2D echocardiographic parameters and laboratory findings
Indexed
V
max
(ml/m²)
Indexed
V
olp
(ml/m²)
Indexed
V
min
(ml/m²)
Indexed
PEV
(ml/m²)
Indexed
AEV
(ml/m²)
Indexed
TEV
(ml/m²)
Glucose (mg/dl)
r
0.153 0.252 0.182 –0.034 0.204 0.075
P
0.108 0.007 0.055 0.725 0.031 0.429
HbA
1c
(%)
r
0.288 0.367 0.294 0.006 0.301 0.192
P
0.002
<
0.001 0.002 0.954 0.001 0.043
BMI (kg/m
2
)
r
0.430 0.441 0.368 0.135 0.340 0.325
P
<
0.001
<
0.001
<
0.001 0.154
<
0.001
<
0.001
TG (mg/dl)
r
0.152 0.248 0.136 –0.047 0.239 0.089
p
0.110 0.008 0.153 0.625 0.011 0.350
hsCRP (mg/l)
r
0.412 0.420 0.320 0.103 0.371 0.308
p
<
0.001
<
0.001 0.001 0.281
<
0.001 0.001
Uric acid
r
0.362 0.378 0.297 0.125 0.283 0.253
(mg/dl)
p
<
0.001
<
0.001 0.001 0.190 0.002 0.007
Mitral A (cm/s)
r
0.328 0.380 0.292 –0.002 0.321 0.232
p
<
0.001
<
0.001 0.002 0.981 0.001 0.014
Mitral E
′
(cm/s)
r
–0.274 –0.258 –0.211 –0.094 –0.202 –0.226
p
0.003 0.006 0.026 0.323 0.033 0.017
Mitral A
′
(cm/s)
r
0.278 0.281 0.310 0.064 0.117 0.138
p
0.003 0.003 0.001 0.504 0.220 0.147
E/E
′
ratio (cm/s)
r
0.279 0.286 0.255 0.059 0.197 0.192
p
0.003 0.002 0.007 0.539 0.037 0.028
E/A ratio (cm/s)
r
0.085 0.129 0.288 –0.050 –0.135 –0.140
p
0.374 0.177 0.002 0.604 0.154 0.142
LA: left atrium, BMI: body mass index, TG: triglycerides, hsCRP: high-sensi-
tivity C-reactive protein, PEV: passive emptying volume, AEV: active emptying
volume, TEV: total emptying volume.
Table 6. Univariate and multivariate analysis for predictors of LA volume and function of the study population
Univariate analysis
Multivariate analysis
Parameters
DM2 HT HL Age
BMI hsCRP Uric acid DM HT HL Age
BMI hsCRP Uric acid
LA diameter (mm)
<
0.001
<
0.001 0.028
1
<
0.001
<
0.001 0.003 0.001
0.227 0.001 0.005 0.002
<
0.001 0.879 0.194
Indexed V
max
(ml/m²)
<
0.001
<
0.001 0.003
<
0.001
<
0.001
<
0.001
<
0.001
0.438 0.056 0.100 0.001 0.004 0.191 0.064
Indexed V
olp
(ml/m²)
<
0.001
<
0.001
<
0.001
<
0.001
<
0.001
<
0.001
<
0.001
0.991 0.181 0.244 0.003 0.016 0.226 0.042
Indexed V
min
(ml/m²)
<
0.001
<
0.001 0.007
<
0.001
<
0.001 0.001 0.001
0.869 0.171 0.334 0.069 0.099 0.371 0.034
Indexed PEV (ml/m²)
0.66 0.268 0.971 0.171 0.164 0.281 0.190
–
–
–
–
–
–
–
Indexed AEV (ml/m²)
<
0.001
<
0.001 0.001 0.001
<
0.001
<
0.001 0.002
0.822 0.623 0.476 0.010 0.064 0.383 0.486
Indexed TEV (ml/m²)
0.004 0.001 0.051
<
0.001
<
0.001 0.001 0.007
0.189 0.259 –
0.003 0.020 0.443 0.418
LA passive emptying
fraction (%)
0.003 0.052 0.011 0.169 0.044 0.065 0.338
0.150 –
0.438 –
0.897 –
–
LA active emptying
fraction (%)
0.386 0.769 0.499 0.393 0.718 0.430 0.968
–
–
–
–
–
–
–
LA total emptying
fraction (%)
0.05 0.117 0.162 0.293 0.148 0.395 0.363
–
–
–
–
–
–
–
DM: diabetes mellitus, HT: hypertension, HL: hyperlipidaemia, BMI: body mass index, hsCRP: high-sensitivity C-reactive protein, LA: left atrium, PEV: passive
emptying volume, AEV: active emptying volume, TEV: total emptying volume.