CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 3, April 2012
AFRICA
139
(ROC) = 0.1989] or QRS duration (ROC = 0.2558) that could
predict a diagnosis of pure TIC with a high sensitivity and
specificity.
The pre- and post-treatment echocardiographic parameters
of pure and impure TIC are displayed in Table 3. In the pure
TIC group, the mean LVEF improved significantly from 32.4
± 9.5 to 53.2 ± 10.5% (
p
< 0.001). Both the LVIDd (
p
= 0.004)
and LVIDs (
p
= 0.001) dimensions improved significantly post
treatment. There was no significant decrease in LA size pre-
and post treatment. In the impure TIC group, the mean LVEF
improved significantly from 29.2 ± 10.0 to 55.0 ± 9.9% (
p
<
0.001). The LVIDs dimension (
p
= 0.04), but not the LVIDd
dimension, improved significantly post treatment. There was
no change in LA size pre- and post treatment in the impure TIC
group. TIC patients with dilated ventricles at presentation were
more likely to have residual LV dilatation at follow up (
r
= 0.68,
p
= 0.002).
We identified variable rates of LV improvement after control
of the tachycardia. Thirteen pure TIC patients had at least
three echocardiograms performed: at initial diagnosis, when
improvement of LV function was documented, and at last
available follow up. In seven (54%) patients, maximal recovery
was noted early, within the first three to six months after
control of the tachycardia (Fig. 1: group A). All seven patients
had prompt, effective rate or rhythm control of the causative
tachycardia. However, in six (46%) patients, maximal LV
improvement occurred late, after six months, with improvement
seen even after a year (Fig. 2: group B). Of these six patients,
two had LVEF < 20%. Two AF patients had initial suboptimal
heart rate control as defined by the AFFIRM trial targets
6
before
AVNA and PPM implantation, and two patients had ATs that
were initially difficult to control with medical therapy (Table 4).
Seventeen patients with pure TIC who had an improvement in
LVEF > 50% after control of the tachycardia were compared to
17 control patients with normal echocardiograms, matched for
age and LVEF (Table 5). Patients with pure TIC had a trend of
increased residual LVIDd dimensions compared to the control
group, indicating a persistence of adverse LV remodelling late
after control of the causative tachycardia (
p
= 0.06). There
were no significant differences between the LVIDs and LA
dimensions between the two groups.
Discussion
Our relatively large study of TIC has several important findings.
This is the first study to compare patients with pure and impure
TIC. Patients with impure TIC had shorter durations of dyspnoea
and more clinical signs of heart failure at presentation. Our study
supports the observation that patients with underlying structural
heart disease may develop LV dysfunction more quickly and
present earlier with symptoms and signs of heart failure.
4
At initial presentation, TIC may be indistinguishable from
DCMO with secondary tachycardia – the chicken–egg dilemma.
5
Pure TIC patients had a better effort tolerance (NYHA class),
complained of more palpitations and had fewer clinical signs
of heart failure at initial presentation compared to patients with
DCMO. Pure TIC patients also had fewer ECG conduction
system abnormalities (with shorter QRS durations, and were less
likely to have Q waves, LVH and repolarisation abnormalities)
compared to patients with DCMO.
A previous study showed that certain electrocardiographic
presentation.
Despite significant differences in LVIDd dimensions and
QRS duration between the two groups, we could not identify
any LVIDd dimension [area under the receiver operating curve
TABLE 2. COMPARISON OF CLINICAL,
ELECTROCARDIOGRAPHICAND ECHOCARDIOGRAPHIC
FEATURES OF PURE TICAND DCMO MATCHED FORAGE,
GENDERAND LVEF
Patient demo-
graphics and
clinical features
Pure TIC group
(
n
= 25)
n
(
%
)
DCMO group
(
n
= 25)
n
(
%
)
p
-value*
Age
46 (16–67)
46 (21–65)
0.846
¶
Gender
Male
19 (76)
19 (76)
Female
6 (24)
6 (24)
1.00
NYHA
NYHA I, II
9 (36)
4 (16)
NYHA III, IV
16 (64)
21 (84)
0.02
Palpitations
Yes
21 (84)
12 (48)
No
4 (16)
13 (52)
0.007
¶
Mann-Whitney test, *Chi-square test,
#
Student’s
t
-test.
Signs of heart failure
Yes
12 (48)
21 (84)
No
13 (52)
4 (16)
0.007
ECG features
Sinus rhythm
Yes
5 (20)
19 (76)
No
20 (80)
6 (24)
<
0.001
LA enlargement
Yes
3 (12)
8 (32)
No
5 (20)
11 (44)
0.546
Unable to assess
17 (68)
6 (24)
Q waves
Yes
1 (4)
10 (40)
No
24 (96)
15 (60)
0.002
LBBB
Yes
2 (8)
6 (24)
No
23 (92)
19 (76)
0.123
RBBB
Yes
1 (4)
0 (0)
No
24 (96)
25 (100)
0.5
LVH
Yes
4 (16)
14 (56)
No
21 (84)
11 (44)
0.004
Repolarisation abnormalities
Yes
16 (64)
22 (88)
No
9 (36)
3 (12)
0.048
QRS width (ms)
88 (82
-
102)
100 (92
-
110)
0.024
¶
RV
6
(mm)
15.8
±
7.5
15.0
±
11.2
0.79
#
RV
6
/R
max
1.84
±
0.8
1.69
±
1.2
0.63
#
Echocardiographic features
LVEF (
%
)
30.8
±
9.5
27.8
±
10.2
0.29
#
LVIDd (cm)
5.7
±
0.7
6.6
±
0.6
<
0.001
#
LVIDs (cm)
4.9
±
0.8
5.7
±
0.6
0.001
#
LA size (cm)
4.1
±
1.0
4.6
±
0.5
0.048
#
