CARDIOVASCULAR JOURNAL OF AFRICA • Vol 22, No 2, March/April 2011
76
AFRICA
P-wave dispersion: relationship to left ventricular
function in sickle cell anaemia
NI OGUANOBI, BJC ONWUBERE, SO IKE, BC ANISIUBA, EC EJIM, OG IBEGBULAM
Summary
Background
: The prognostic implications of P-wave disper-
sion in patients with a variety of cardiac disease conditions
are increasingly being recognised. The relationship between
P-wave dispersion and left ventricular function in sickle cell
anaemia is unknown.
Objective:
This study was aimed at evaluating the relation-
ship between P-wave dispersion and left ventricular function
in adult Nigerian sickle cell anaemia patients.
Methods:
Between February and August 2007, a total of 62
sickle cell anaemia patients (aged 18–44 years; mean 28.27
±
5.58) enrolled in the study. These were drawn from patients
attending the adult sickle cell clinic of the University of
Nigeria Teaching Hospital, Ituku-Ozalla, Enugu. An equal
number of age- and gender-matched normal subjects served
as controls. All the participants were evaluated with elec-
trocardiography and echocardiography. P-wave dispersion
was defined as the difference between the maximum and
minimum P-wave duration measured in a 12-lead electro-
cardiogram.
Results:
P-wave duration and P-wave dispersion were signifi-
cantly higher in patients than in controls. Significant correla-
tion was demonstrated between P-wave dispersion and age in
the patients (
r
=
0.387;
p
=
0.031). A comparison of subsets
of sickle cell anaemia patients and controls with comparable
haematocrit values (30–35%) showed significantly higher
P-wave duration and P-wave dispersion in the patients than
in the controls. The P-wave duration in patients and controls,
respectively, was 111.10
±
14.53 ms and 89.14
±
16.45 ms (
t
=
3.141;
p
=
0.006). P-wave dispersion was 64.44
±
15.86 ms in
the patients and 36.43
±
10.35 ms in the controls (
t
=
2.752;
p
=
0.013). Significant negative correlation was found between
P-wave dispersion and left ventricular transmitral E/A ratio
(
r
=
–0.289;
p
=
0.023).
Conclusion:
These findings suggest that P-wave dispersion
could be useful in the evaluation of sickle cell patients with
left ventricular diastolic dysfunction. Further prospective
studies are recommended to evaluate its prognostic implica-
tion on the long-term disease outcome in sickle cell disease
patients.
Keywords:
P-wave dispersion, left ventricular function, sickle
cell anaemia
Submitted 9/3/10, accepted 3/5/10
Cardiovasc J Afr
2010;
21
: 76–78
DOI: CVJ-21.031
There is increasing recognition of the prognostic implications of
the spatial variations of P-wave duration in normal individuals
and patients with a variety of cardiac disease states.
1-3
P-wave
dispersion is defined as the deference between the maximum
and minimum P-wave duration measured in a 12-lead electrocar-
diogram.
4
It is related to the non-homogeneous and interrupted
conduction of sinus impulse both intra- and interatrially and
is considered a predictor of the occurrence of arrhythmias in
patients with left atrial enlargement, left ventricular hypertrophy
and left ventricular diastolic dysfunction,
5
all of which are signif-
icant findings in sickle cell anaemia.
5,6
There is scant information
on this subject in the literature. The study is undertaken to evalu-
ate the relationship between P-wave dispersion and left ventricu-
lar function in adult Nigerian sickle cell anaemia patients.
Methods
A cross-sectional study was carried out on 62 sickle cell anaemia
patients seen at the adult sickle cell clinic of the University of
Nigeria Teaching Hospital (UNTH), Ituku-Ozalla, Enugu from
February to August 2007. An equal number of age- and gender-
matched normal subjects served as controls. All the participants
were evaluated with electrocardiography and echocardiography.
Resting 12-lead electrocardiography was performed on all
subjects using a Cardioline Ar-600 model electrocardiography
machine at a paper speed of 25 mm/s and standardised at 0.1
mV/mm. A single observer analysed the electrocardiogram. The
P-wave was measured from the beginning of the P-wave deflec-
tion from the isoelectric line to the end of the deflection returning
to the isoelectric line. If the beginning or end of the deflection
could not be satisfactorily defined, that lead was not used. The
difference between the maximum and minimum P-wave dura-
tion was taken as the P-wave dispersion.
4
Echocardiography was done using a Hewlett Packard Sonos
2500 echocardiography machine with 3.7-MHz transducer. The
following measurements were taken in the standard positions as
recommended by the American Society of Echocardiography:
7,8
left atrial dimension, aortic root dimension, left ventricular end-
systolic dimension, left ventricular end-diastolic dimension and
end-diastolic volumes, velocities of E and A waves, isovolumic
relaxation time and E-wave deceleration time, left ventricular
ejection fraction, fractional shortening, and velocity of circum-
ferential shortening.
Ethical clearance for the study was obtained from the ethics
committee of UNTH, Enugu. Prior informed consent was
obtained from all the participants in the study.
Department of Medicine, University of Nigeria Teaching
Hospital, Enugu, Nigeria
NI OGUANOBI, MB BS, FWACP,
BJC ONWUBERE, MB BS, Dip (Cardiol), FWACP, FMCP
SO IKE, MB BS, FMCP
BC ANISIUBA, MB BS, FMCP
EC EJIM, MB BS, FWACP
Department of Haematology, University of Nigeria Teaching
Hospital, Enugu, Nigeria
OG IBEGBULAM, MB BS, FWACP
