CARDIOVASCULAR JOURNAL OF AFRICA • Vol 23, No 7, August 2012
386
AFRICA
Clinical and echocardiographic characteristics of the patients
are shown in Table 1. All patients underwent a standard
12-lead electrocardiogram and an ultrasound examination,
which included a specific evaluation of atrio-ventricular, inter-
ventricular and intra-ventricular dyssynchrony. Examinations
(M mode, two dimensional and Doppler evaluation) were
performed using ultrasonographic equipment (General Electric
VIVID 7 PRO).
According to QRS duration, the patients were divided into
two groups. Group 1 included eight patients with a QRS duration
≥
120 ms and all presented with a left bundle branch block
(LBBB). Group 2 included 32 patients with a narrow QRS
<
120 ms.
Assessment of AVD: parameters collected included the
duration of transmitral pulsed Doppler flow (LVFT) and the
length of the cardiac cycle (RR). The mean left ventricular filling
time to cardiac cycle (LVFT/RR × 100
<
40%) defined atrio-
ventricular dyssynchrony.
Assessment of inter-VD: the pulmonary pre-ejection time
(PPET) was measured from the beginning of the QRS complex
to the beginning of the pulmonary flow velocity curve, recorded
by pulse-wave (PW) Doppler in the left parasternal short-axis
view. The aortic pre-ejection time (APET) was measured from
the beginning of the QRS complex to the beginning of the aortic
flow velocity curve, recorded by PW Doppler in the apical
five-chamber view. The difference between the two values
determined the inter-ventricular mechanical delay (IVMD); an
IVMD
>
40 ms was considered as the cut-off value for inter-
ventricular dyssynchrony.
Assessment of intra-LVD: we determined by pulsed tissue
Doppler the electrosystolic delay (ESD) from the onset of the
QRS complex to the positive peak systolic (Sa) velocity for four
basal segments (septal, lateral, inferior and anterior). Intra-LVD
was considered to be present if one or more absolute differences
(
Δ
S
)
>
40 ms were found between two segments.
Statistical analysis
Data were collected and analysed with the software EPI INFO
version 6.04 and Microsoft Excell 2010. Continuous variables
were presented as mean
±
standard deviation. Statistical analysis
was performed with Fischer’s exact test for a significance
level of 5% for the comparison of proportions. Comparisons
between frequencies in the two groups were performed using the
Chi-square test. Correlations between electrocardiographic and
echocardiographic parameters were explored using Pearson’s
correlation.
Results
Overall, the mean age was 54.7
±
168 years, and patients with
QRS
≥
120 ms were older than those with narrow QRS (67.2
±
13.6 vs 51.5
±
15.8 ms,
p
=
0.01) (Table 1). Most patients were
male (57.5%). Systolic and diastolic left ventricular dysfunction,
left ventricular end-diastolic dysfunction (LVEDD), systolic
right ventricular dysfunction, and degree of mitral regurgitation
were similar in the two groups. AVD was present in 16 patients
(40%), inter-VD in 19 patients (47.5%) and intra-LVD in 28
patients (70%). Two patients (5%) did not exhibit dyssynchrony.
AVD alone was present in two patients (5%), inter-VD alone
in five patients (12.5%) and intra-LVD alone in 10 patients
(25%). Four patients (10%) had at the same time AVD, inter-VD
and intra-LVD. 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)
and the duration of LV filling time to cardiac cycle showed no
difference between the two groups (Table 1).
In the sub-group of 16 patients with AVD, the mean left
TABLE 1. CLINICALAND ECHOCARDIOGRAPHIC CHARACTERISTICS OF THE PATIENTS
All patients
(
n
=
40)
Group 1 (QRS
≥
120 ms)
(
n
=
8 patients)
Group 2 (QRS
<
120 ms)
(
n
=
32 patients)
p
-value
(group 1 vs group 2)
Age (years)
54.7
±
16.8
67.2
±
13.6
51.5
±
15.8
0.01
Males (
n
, %)
23 (57.5)
5 (62.5)
18 (56.3)
0.9
NYHA class III (
n
, %)
26 (65)
6 (75)
20 (62.5)
0.8
NYHA class IV (
n
, %)
14 (35%)
2 (25)
12 (37.5)
0.8
QRS width (ms)
100
±
32.9
157.5
±
29.1
85.6
±
10.4
0.03
PR interval (ms)
180.7
±
31.4
180
±
4
180.9
±
29.2
0.94
LVEF (%)
29
±
5
31.3
±
3.3
28
±
5
0.14
LVEDD (mm)
66.7
±
6.6
67.9
±
6.1
66.4
±
6.8
0.58
LVESD (mm)
57.7
±
6.2
58.8
±
5.2
57.3
±
6.5
0.55
E/A
1.5
±
1.1
1.7
±
1
1.9
±
0.9
0.64
DT (ms)
116
±
5
125.3
±
42.7
114.3
±
52.3
0.6
Mitral regurgitation (degree)
1.5
±
0.5
1.6
±
0.5
1.5
±
0.5
0.64
PASP (mmHg)
42.9
±
9
43.3
±
17.5
42.8
±
15.3
0.93
SDTI
11.4
±
2.5
11.6
±
1.2
11.4
±
2.7
0.58
LVFT/RR (%)
40.3
±
8.3
42.3
±
11.8
39.8
±
7.3
0.45
IVMD (ms)
38.6
±
19.3
54.4
±
10.8
36.2
±
18.7
0.01
ESD (ms)
66.5
±
46.9
75.6
±
28.9
64.2
±
50.6
0.54
NYHA: NewYork Heart Association; LVEF: left ventricular ejection fraction; LVEDD: left ventricular end-diastolic diameter; LVESD: left ventricular
end-systolic diameter; PASP: pulmonary artery systolic pressure; E/A: ratio of E wave (early filling) and A wave (atrial contraction) of mitral valve inflow
in pulsed Doppler; DT: deceleration time of early filling velocity; SDTI: right ventricular S peak in tissue Doppler imaging; LVFT/RR: left ventricular fill-
ing time to cardiac cycle; IVMD: inter-ventricular mechanical delay; ESD: electrosystolic delay; the bold emphasis marks the significant differences with
p
-value
<
0.05.
