CARDIOVASCULAR JOURNAL OF AFRICA • Vol 24, No 1, January/February 2013
166
AFRICA
=
69) vs 33.8
±
6 (
n
=
24),
p
=
0.52]. The measurements of the aortic
sinuses in all patients was compared with the predicted size for age
and BSA, this was 34.6
±
6 mm vs 30.9
±
2.9 mm (
p
<
0.001.)
Conclusion
: This study confirms progressive aortic root dialatation
in patients with TOF. The mechanism of this appears to be complex,
as early repair, type of palliation or primary repair does not provide
protection against late aortic dilatation. Routine follow up of post-
operative patients with TOF for aortic root dilatation and the role of
preventive therapy needs further evaluation.
438: INCREASED REGIONAL DEFORMATION OF THE
LEFT VENTRICLE IN CHILDREN WITH A RAISED BODY
MASS INDEX: IMPLICATIONS FOR FUTURE CARDIOVAS-
CULAR HEALTH
David Black
1,2
, Jen Bryant
1,3
, Lucy Davies
3
, Charles Peebles
2
, Hazel
Inskip
1,3
, Keith Godfrey
1,3
, Joseph Vettukattil
2
, Mark Hanson
1,3
1
Institute of Developmental Sciences, Human Development and
Health Academic Unit, Southampton, UK
2
Paediatric Cardiology and Cardiothoracic Radiology, University
Hospital Southampton, UK
3
MRC Lifecourse Epidemiology Unit, University of Southampton,
and NIHR Southampton, UK
Background:
The prevalence of obesity continues to increase in the
developing world. The effects of obesity on the cardiovascular system
include changes in systolic and diastolic function. More recently
obesity has been linked with impairment of longitudinal myocar-
dial deformation properties in children. We sought to determine the
effect of a raised body mass index (BMI) on cardiac deformation in
a group of children taking part in the population-based Southampton
Women’s Survey.
Methods:
A sample of 68 children aged nine years old had assess-
ments of longitudinal myocardial deformation in the basal septal
segment of the left ventricle using two-dimensional speckle track-
ing echocardiography. Parameters of after-load and pre-load, which
may influence deformation, were determined from cardiac magnetic
resonance imaging. BMI was determined from the child’s height and
weight at the time of the echocardiogram.
Results:
A higher BMI was associated with an increase in longitudi-
nal myocardial deformation or strain in the basal septal segment of
the left ventricle (
r
=
0.41,
p
<
0.001), but was not related to contrac-
tility or strain rate in this part of the heart (
r
=
0.04,
p
=
0.75). The
end-diastolic volume of the left ventricle increased with increasing
BMI (
r
=
0.33,
p
=
0.011).
Conclusion:
Regional deformation in the left ventricle increases
significantly with increasing BMI, while normal contractility is
maintained. This may be explained by the increased pre-load of the
left ventricle due to increased somatic growth. The long-term impli-
cations of this altered physiology need on-going follow up.
439: IMPAIRED RIGHT VENTRICULAR CONTRACTILE
RESERVE LATE AFTER SURGICAL CLOSURE OF ISOLAT-
ED ATRIAL SEPTAL DEFECT
Thomas Moller
1
, Per Morten Fredriksen
2
, Henrik Holmstram
3
, Erik
Thaulow
3
1
Vestfold Hospital Trust, Tønsberg, Norway
2
University College of Health Sciences, Campus Kristiania, Oslo,
Norway
3
Oslo University Hospital Rikshospitalet, Oslo, Norway
Background:
Impaired aerobic exercise capacity and abnormally
elevated right ventricular systolic pressure during exercise have
previously been demonstrated in asymptomatic adolescents after
surgical closure of isolated atrial septal defect early in life. We stud-
ied right ventricular contractile reserve during incremental exercise
in this patient group. The study hypothesis was that differences in
aerobic exercise capacity and pulmonary pressure response to exer-
cise might be combined with differences in right ventricular systolic
function during exercise.
Methods:
Seventeen asymptomatic patients (age 15–23 years,
12 females, median age at defect closure 53 months) and 22 age-
matched healthy control subjects were studied by echocardiography
at rest and during recumbent bicycle exercise until a target heart
rate of 160 bpm. M-mode images and colour-coded tissue Doppler
recordings from apical four-chamber view were analysed offline.
Results:
Patients had lower tricuspid annular peak systolic excursion
(TAPSE) (14.2
±
3.1 mm) at rest compared to controls (22.3
±
2.9,
p
<
0.001). Correspondingly, the maximal TAPSE during exercise was
reduced in the patient group (20.5
±
4.5 vs 31.4
±
4.1,
p
<
0.001).
Peak systolic tricuspid annular velocity (S’) was significantly lower
in the patient group both at rest (patients 6.8
±
1.8 cm/s, controls 9.7
±
1.6 cm/s,
p
<
0.001) and as the highest measured S’ during exercise
(11.7
±
2.8 cm/s vs 15.3
±
2.7 cm/s,
p
<
0.001). Isovolumetric right
ventricular acceleration (IVA), measurable in the tricuspid annulus
of
n
=
13/22, was reduced in the patient group at pre-exercise (1.1
±
0.5 vs 1.8
±
0.6c m/s
2
,
p
<
0.001, median heart rate 88/91.5), but
tended towards equalisation for the highest measured IVA during
exercise (3.5
±
1.4 vs 4.2
±
1.2 cm/s
2
,
p
=
0.145, median heart rate
159.5/149.5 at peak IVA).
Conclusions:
Asymptomatic adolescent patients with surgically
closed isolated atrial septal defect have impaired right ventricular
contractile reserve, most markedly demonstrated in reduced longitu-
dinal shortening.
440: QTC PROLONGATION PRIOR TO ANGIOGRAPHY
PREDICTS POOR OUTCOME AND ASSOCIATES SIGNIFI-
CANTLY WITH LOWER LEFT VENTRICULAR EJECTION
FRACTIONS AND HIGHER LEFT VENTRICULAR END-
DIASTOLIC PRESSURES
Pieter Van Der Bijl, Marshall Heradien, Paul Brink, Anton Doubell
Division of Cardiology, Department of Medicine, Stellenbosch
University and Tygeberg Academic Hospital, South Africa
Background
:
QT prolongation on the surface ECG is associated
with sudden cardiac death. The cause of QT prolongation in ischae-
mic heart disease (IHD) patients remains unknown, but may be due
to a complex interplay between genetic factors and impaired systolic
and/or diastolic function through, as yet, unexplained mechanisms.
It was hypothesised that QT prolongation before elective coronary
angiography is associated with an increased mortality at six months.
Methods:
Complete records of patients (
n
=
321) who underwent
coronary angiography were examined for QT interval corrected for
heart rate (QTc) (Bazett’s formula), left ventricular ejection fraction
(LVEF), left ventricular end-diastolic pressure (LVEDP) and corre-
lated with triple-vessel coronary artery disease (TVCAD) and other
known IHD risk factors (hypercholesterolaemia, diabetes mellitus,
smoking, hypertension or a family history of IHD). Patients were
designated LQTc when they had prolonged QTc intervals, or NQTc
when the QTc interval was normal. Patients with atrial fibrillation,
bundle branch blocks, no ECG in the 24 hours before angiography,
or a creatinine level
>
200 µmol/l were excluded. Survival was deter-
mined telephonically at six months.
Results:
Twenty-eight per cent of the total population had a LQTc.
During follow up 15 patients (4.7%) died suddenly, 73% of whom
had a LQTc. LQTc was significantly associated with mortality
(LQTc: 12% vs NQTc: 1.7%;
p
<
0.01), and with lower, but normal,
LVEF (LQTc: 52.9
±
15.4% vs NQTc: 61.6
±
13.6%;
p
<
0.01),
higher LVEDP at LVEF
>
45% (LQTc: 19.2
±
9.0 mmHg vs NQTc:
15.95
±
7.5 mmHg;
p
<
0.05), hypercholesterolaemia and a negative
family history of IHD.
Conclusion:
In patients with sinus rhythm and normal QRS width,
QTc prolongation before coronary angiography predicts increased
mortality at six months. QTc also strongly associates with left
ventricular systolic and diastolic dysfunction, hypercholesterolaemia
and a negative family history of IHD.
