CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 7, August 2012
AFRICA
385
Prevalence of cardiac dyssynchrony and correlation
with atrio-ventricular block and QRS width in dilated
cardiomyopathy: an echocardiographic study
JB ANZOUAN-KACOU, MP NCHO-MOTTOH, C KONIN, AR N’GUETTA, KA EKOU, BJ KOFFI, KE SOYA,
ME TANO, R ABOUO-N’DORI
Abstract
Introduction:
Cardiac dyssynchrony causes disorganised
cardiac contraction, delayed wall contraction and reduced
pumping efficiency. We aimed to assess the prevalence of
different types of dyssynchrony inpatients with dilated cardio-
myopathy (DCM), and to establish the correlation between
atrio-ventricular block and atrio-ventricular dyssynchrony
(AVD), and between impaired intra-ventricular conduction
and the existence of inter-ventricular dyssynchrony (inter-
VD) and intra-left ventricular dyssynchrony (intra-LVD).
Methods:
We included 40 patients in New York Heart
Association stage III or IV, admitted consecutively with DCM
with severe left ventricular dysfunction (left ventricular end-
diastolic diameter
≥
60 mm and/or
≥
30 mm/m²) and left
ventricular ejection fraction
<
35%. Electrocardiographic
and echocardiographic data were evaluated in all patients.
Patients were divided into two groups: group 1: eight
patients, with a QRS duration
≥
120 ms, and all presented
with left bundle branch block; group 2: 32 patients with a
narrow QRS
<
120 ms.
Results:
Overall, the mean age was 54.7
±
16.8 years and
patients in group 1 were older (67.2
±
13.6 vs 51.5
±
15.8
years,
p
=
0.01). The prevalence of atrio-ventricular dyssyn-
chrony (AVD), inter-VD and intra-LVD was respectively 40,
47.5 and 70%. Two patients (5%) did not exhibit dyssyn-
chrony. AVD was present with a similar frequency in the
two groups (37.5% in group 1 vs 40.6% in group 2,
p
=
0.8).
There was no correlation of the magnitude of AVD with
the duration of the PR interval (from the beginning of the
P wave to the beginning of the QRS complex) (
r
2
=
0.02,
p
=
0.37) or the QRS width (
r
²
=
0.01,
p
=
0.38).A greater propor-
tion of patients with inter-VD was observed in group 1 (87.5
vs 60%,
p
=
0.03). There was a trend towards a more impor-
tant inter-ventricular mechanical delay according to QRS
width (
r
2
=
0.009,
p
=
0.06). The proportion of intra-LVD was
similar in all groups, with a high prevalence (87.5% in group
1 and 65.6% in group 2,
p
=
0.39).
Conclusion:
The assessment of cardiac dyssynchrony is
possible in our country. Intra-ventricular mechanical
dyssynchrony had a high prevalence in patients with DCM,
irrespective of the QRS width. These data emphasise the
usefulness of echocardiography in the screening of patients.
Keywords:
heart failure, cardiomyopathy, dyssynchrony, echo-
cardiography, Africa
Submitted 3/4/11, accepted 28/3/12
Cardiovasc J Afr
2012;
23
: 385–388
DOI: 10.5830/CVJA-2012-032
In dilated cardiomyopathy (DCM), alterations in cardiac
structure and function result in regions of early and late
contraction, known as dyssynchrony.
1
This dyssynchrony
disorganises cardiac contraction, delays wall contraction and
reduces pumping efficiency.
1,2
Morbidity and mortality rates
are higher in patients with severe left ventricular systolic
dysfunction and ECG-derived prolonged QRS interval than in
those with normal QRS duration.
3
Three types of dyssynchrony may occur: atrio-ventricular
dyssynchrony (AVD) with a discordance of contraction between
the atria and ventricles, inter-ventricular dyssynchrony (inter-
VD) with a discordance between the time of left and right
ventricle contractions, and intra-left ventricular dyssynchrony
(intra-LVD) with a discordance in the contraction of the walls
of the left ventricle. A large number of studies have used
echocardiography to assess dyssynchrony.
1,4
Intra-LVD appears to be the principal factor associated
with contractile impairment and is affected by cardiac
resynchronisation therapy (CRT). CRT has been proven to reduce
symptoms and hospitalisation for heart failure, and to improve
quality of life, exercise capacity and the overall prognosis.
1,4,5
In
this study, we aimed to assess the prevalence of different types
of dyssynchrony in patients with dilated cardiomyopathy, and
to establish the correlation between atrio-ventricular block and
AVD, and between impaired intra-ventricular conduction and the
existence of inter-VD and intra-LVD.
Methods
This prospective study was conducted at the Institute of
Cardiology of Abidjan (ICA) from June to December 2009.
We included patients in New York Heart Association (NYHA)
stage III or IV, admitted consecutively with the following
features: dilated cardiomyopathy with severe left ventricular
dysfunction (left ventricular end-diastolic diameter
>
60 mm
and/or 30 mm/m²) as measured by M-mode echocardiography,
and an ejection fraction
<
35%, (by Simpson’s method). A
total of 40 patients were included. We excluded patients with
non-sinus rhythm or valvular heart disease.
Institute of Cardiology of Abidjan, Abidjan, Ivory Coast
JB ANZOUAN-KACOU, MD,
MP NCHO-MOTTOH, MD
C KONIN, MD
AR N’GUETTA, MD
KA EKOU, MD
BJ KOFFI, MD
KE SOYA
ME TANO, MD
R ABOUO-N’DORI, MD, PhD
