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AFRICA
Cardiovascular Journal of Africa • ABSTRACTS – SA HEART
®
CONGRESS 2019
S42
Single centre experience of congenitally corrected transposition of the great arteries over 17 years
Lenise Swanson
University of Cape Town, Rondebosch, South Africa
Introduction:
Congenitally corrected transposition of the great arteries (CCTGA) is a rare and complex cardiac anomaly, accounting for less than 1% of
all congenital heart defects. Management strategies and outcomes vary according to the associated cardiac defects and functional state of the systemic
ventricle.
Methods:
We conducted a retrospective folder review of patients with confirmed CCTGA from 1 January 2000 - 31 August 2017 to describe the most-
commonly associated cardiac defects, the management strategies and outcomes for these patients. Patients who were last followed up more than 24 months
previously, or whose clinical notes were incomplete, were excluded from this study.
Results:
Thirty-six patients with CCTGA were identified for this study, of which 21 were eligible for inclusion (10 male, 47,6%). Median age at presentation was
2.7 months. Presenting complaints were: murmurs (57.1%), cyanosis (57.1%) and respiratory distress (23.8%). One patient had been diagnosed antenatally.
VSD (85.7%), pulmonary stenosis (47.6%) and PDA (38.1%) were the most commonly associated cardiac lesions. Two patients had associated syndromes or
congenital abnormalities. Eight patients were suitable for biventricular repair for which 3 double switch operations (length of stay 10 - 14 days, mean 12 days),
1 Senning-Rastelli (length of stay 14 days) and 4 pulmonary artery banding procedures were performed. Six patients were selected for the univentricular
pathway, with 5 Glenn shunts and 1 completed Fontan surgery (length of stay 21 days) having been done. Two patients were considered to be inoperable
due to the complexity of their cardiac anatomy. The surgical mortality rate was zero. Pleural effusions and chylothorax were the most common post-surgical
complications (4.7% each). Complete heart block was present in 1 patient (post-Senning-Rastelli) and required permanent pacemaker implantation.
Conclusion:
We demonstrate a varied surgical approach to patients with CCTGA over almost 2 decades. While surgical correction has been shown to render
early successes, long-term follow-up is necessary to monitor for late onset complications. This remains a challenge in our setting.
The unguarded mitral valve orifice associated with the hypoplastic left heart syndrome: A case report
Farirai Fani Takawira*, Greenwood Sinyangwe
#
, Hendrik Mamorare
#
and Eric Schurman
#
*Steve Biko Academic Hospital and University of Pretoria, Hatfield, Pretoria, South Africa.
#
Sunninghill Hospital, Sunninghill, Sandont, South Africa
Introduction:
The unguarded mitral valve orifice is a rare congenital heart defect characterised by the complete agenesis of the mitral valve leaflets and
apparatus. The abnormality leads to free intrauterine regurgitation of the atrioventricular valve orifice and plays a significant role in the maldevelopment of
the left ventricle and aorta. We report on a case of the unguarded mitral valve orifice associated with the hypoplastic left heart syndrome (HLHS). While mitral
valve atresia and aortic valve atresia are known causes for the hypoplastic left heart syndrome, this case highlights how free mitral regurgitation and the
subsequent left ventricular volume loss in the developing heart can lead to development of HLHS.
Methods:
Case report
Results:
A term AGA neonate was delivered by normal vertex delivery to a 32-year-old Para 1, gravida 2 mother. After a few hours he was noted to have
cyanosis, which did not respond to the administration of O2. On examination he had saturations of 83% on 100% FiO2 and he was being ventilated. His pulse
was 125/min, with globally weak volume pulses. BP was 58/33. No cardiomegaly, murmur or CCF. Echocardiography revealed an unguarded mitral valve
orifice. The LV was small and hypoplastic. A small PFO was present, with a dilated left atrium. There was aortic atresia and a hypoplastic ascending aorta. There
was a large PDA with bidirectional shunting present. A diagnosis of the hypoplastic left heart syndrome associated with the unguarded mitral valve orifice
was made. Prostaglandin infusion was started and he underwent a stage 1 Norwood operation with atrial septectomy. Sadly, he died a few days later.
Conclusion:
The unguarded mitral orifice is a rare cardiac malformation. There is free mitral regurgitation with unobstructed to-and-fro flow between the left
atrium and left ventricle. The subsequent decreased LV volume leads to underdevelopment of the LV and the subsequent HLHS, which has a high morbidity
and mortality. Very few cases have been reported in the English literature.
Assessing the diagnostic accuracy of a 5-cable electrocardiogram prototype
Gideon Titus, Hellmuth Weich and Anton Doubell
Division of Cardiology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University and Tygerberg Hospital, Bellville,
South Africa
Introduction:
The 12-lead ECG is a standard part of cardiac assessment. However, it is often omitted, or performed incorrectly. A new 5-cable ECG, which is
easier to perform and could thus decrease the risk of incorrect cable/electrode placement as well as reduce healthcare cost, was created. The primary aim
of this study is to determine whether the diagnostic accuracy (printed tracing) of the 5-cable ECG prototype is sufficient so that it can be used instead of
the standard 12-lead ECG machine. A secondary aim is to determine whether the 5-cable ECG prototype can use machine learning algorithms to correctly
distinguish normal from abnormal ECGs.
Methods:
ECGs were performed on 200 adult patients (age ≥18 years) who presented to Tygerberg Hospital’s coronary care unit and cardiac outpatients.
A 12-lead ECG was performed, immediately followed by a 5-cable ECG. These printouts were randomised and interpreted blindly by an independent
cardiologist for both classification (normal, abnormal, variations not necessarily indicating pathology, unclassified) and diagnosis. The 5-cable ECG prototype
was trained in accordance with a pre-existing ECG database to classify ECGs as normal or abnormal through the use of machine learning algorithms in a
neural network developed by the Stellenbosch University Biomedical Engineering Research Group.
Results:
The 5-cable prototype generated interpretable ECGs in 49% (n=98) of cases. Analysis of the 98 ECGs determined that use of the 5-cable printout was
comparable to use of the standard 12-lead ECG printout in order to assess classification (p>0.1). However, diagnosis differed significantly from diagnosis based
on the 12-lead ECG (p<0.0001). The 5-cable ECG prototype neural network could distinguish normal from abnormal with an accuracy of 70%.
Conclusion:
The 5-cable machine is still a prototype which requires refining. Its tracings cannot be used for diagnostic purposes but can generate ECGs
leading to an accurate classification of normal vs. abnormal. The neural network algorithms have potential for use in future screening programmes.