CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 3, April 2012
136
AFRICA
The clinical, electrocardiographic and echocardiographic
characteristics and long-term outcome of patients with
tachycardia-induced cardiomyopathy
ASHLEY CHIN, MOTASIM BADRI, NB NTUSI, ANDRZEJ OKREGLICKI
Introduction:
The clinical, electrocardiographic and echocar-
diographic features and long-term outcome of patients with
tachycardia-induced cardiomyopathy (TIC) have not been
well described in the past.
Methods:
A retrospective study was performed at our
institution of patients with a diagnosis of TIC.
Results:
Thirty-three patients with pure TIC and 12 patients
with impure TIC were identified. Compared to patients with
dilated cardiomyopathy (DCMO), pure TIC patients were
less symptomatic, as judged by NYHA class (
p
=
0.02), they
had fewer clinical signs of heart failure (
p
=
0.007) and were
more likely to report palpitations (
p
= 0.007) at presenta-
tion. Electrocardiographically, pure TIC patients had fewer
Q waves (
p
=
0.002), less left ventricular hypertrophy (LVH)
(
p
=
0.004) and repolarisation abnormalities (
p
=
0.048), and
shorter QRS durations (
p
=
0.024). Echocardiographically,
pure TIC patients had significantly smaller left ventricular
internal diameter in diastole (LVIDd) (
p
<
0.001), ventricu-
lar internal diameter in systole (LVIDs) (
p
=
0.001) and
left atrial dimensions (
p
=
0.048) at presentation compared
to DCMO patients. Patients with pure TIC had a trend
towards increased residual LVIDd dimensions compared to
a control group with normal echocardiograms, indicating a
persistence of adverse LV remodelling late after control of
the causative tachycardia (
p
=
0.06). Recurrent tachycardia
occurred in three patients, which resulted in a precipi-
tous decline in left ventricular ejection fraction (LVEF).
Conclusions:
This study is the first to compare features of
pure and impure TIC. Patients with pure TIC had shorter
QRS durations, fewer Q waves, and less LVH and repo-
larisation abnormalities at presentation compared to DCMO
patients. TIC patients tended to have smaller LVIDd dimen-
sions at presentation and have persistence of adverse LV
remodelling, as characterised by persistent enlargement of
LVIDd dimensions, at late follow up.
Keywords:
tachycardia-induced cardiomyopathy, cardiomyo-
pathy, tachycardia, tachycardiomyopathy, tachycardia-mediated
cardiomyopathy
Submitted 2/1/11, accepted 9/5/11
Cardiovasc J Afr
2012;
23
: 136–142
DOI: 10.5830/CVJA-2011-019
Tachycardia-induced cardiomyopathy (TIC) is an important
reversible cause of cardiomyopathy (CMO) and heart failure.
Until recently, TIC was considered to be a rare cause of
reversible left ventricular (LV) dysfunction.
1
Over the past few
years, several publications have established that this disease
is much more prevalent than once thought,
2,3
but most reports
of TIC have been isolated case reports or small retrospective
cohorts comprising less than 20 to 30 patients.
LV dysfunction may either develop in the setting of no
underlying structural heart disease, so-called ‘pure’ TIC, or in
the setting of pre-existing structural heart disease, ‘impure’TIC.
4
TIC studies have mostly enrolled patients with pure TIC and
have excluded those with impure TIC. However, impure TIC is
probably more common than pure TIC,
4
but less well investigated
and reported in the literature.
The presenting clinical, electrocardiographic and
echocardiographic features of TIC have not been well described.
At presentation, TIC may be indistinguishable from dilated
cardiomyopathy (DCMO) with secondary tachycardia – the
so-called ‘chicken–egg dilemma’.
5
Factors influencing the rate
and extent of recovery of LV function are poorly understood.
Lastly, the long-term outcome and prognosis of patients with TIC
have not been well defined.
In order to examine some of these questions, we conducted
a retrospective study of TIC at our institution. In this study, we
report the clinical, electrocardiographic and echocardiographic
features of a relatively large cohort of 45 patients with pure and
impure TIC. One of the aims of this study was to identify clinical,
electrocardiographic and echocardiographic features that could
help the clinician recognise this condition, by comparing 25
patients with pure TIC with 25 patients with DCMO. We report
on the response to treatment and compare 17 patients who had
normalised LV function after control of the tachycardia with
17 control patients with normal echocardiograms, to assess for
persistence of adverse LV remodelling. Finally, we report on the
long-term outcome and prognosis of these patients.
Methods
We conducted a retrospective study of patients with a diagnosis
of TIC who presented to the cardiac clinic at Groote Schuur
Hospital, Cape Town between 1994 and 2009. The study
protocol was approved by the University of Cape Town’s ethics
committee.
We included patients with a diagnosis of TIC made by
the attending cardiologist if the presenting left ventricular
ejection fraction (LVEF) was < 50% and there was an LVEF
improvement of
≥
5% after rate or rhythm control of the
tachycardia with medical or ablative therapy. Patients were
included in the pure TIC group if no underlying structural heart
disease could be identified. Patients with a prior history of
Cardiac Clinic, Groote Schuur Hospital, and Department of
Medicine, University of Cape Town, Cape Town,
South Africa
ASHLEY CHIN, MB ChB, MPhil,
MOTASIM BADRI, PhD
NB NTUSI, MB ChB
ANDRZEJ OKREGLICKI, MB ChB, MMed
