The pattern of congenital heart disease in Yoruba children of Western Nigeria

A systematic review of trends and patterns of congenital heart disease in children in Nigeria from 1964-2015

BACKGROUND

Congenital heart diseases cause significant childhood morbidity and mortality. Several restricted studies have been conducted on the epidemiology in Nigeria. No truly nationwide data on patterns of congenital heart disease exists.

OBJECTIVES

To determine the patterns of congenital heart disease in children in Nigeria and examine trends in the occurrence of individual defects across 5 decades.

METHOD

We searched PubMed database, Google scholar, TRIP database, World Health Organisation libraries and reference lists of selected articles for studies on patterns of congenital heart disease among children in Nigeria between 1964 and 2015. Two researchers reviewed the papers independently and extracted the data. Seventeen studies were selected that included 2,953 children with congenital heart disease.

RESULTS

The commonest congenital heart diseases in Nigeria are ventricular septal defect (40.6%), patent ductus arteriosus (18.4%), atrial septal defect (11.3%) and tetralogy of Fallot (11.8%). There has been a 6% increase in the burden of VSD in every decade for the 5 decades studied and a decline in the occurrence of pulmonary stenosis. Studies conducted in Northern Nigeria demonstrated higher proportions of atrial septal defects than patent ductus arteriosus.

CONCLUSIONS

Ventricular septal defects are the commonest congenital heart diseases in Nigeria with a rising burden.

Epidemiological characterization of congenital heart disease in São Miguel Island, Azores, Portugal

OBJECTIVES

This study aimed to characterize the prevalence of congenital heart disease (CHD) in children born alive in São Miguel island from January 1992 to December 2001.

METHODS

Based on the Azorean Registry of CHD, which includes complete clinical and personal information, 189 patients were diagnosed.

RESULTS

During this 10-year period, the average prevalence of CHD is 9.16 per 1,000 live births (range 4.77-12.75). The most frequent cardiac malformations found were: ventricular septal defect (38.1%), atrial septal defect (12.2%) and patent ductus arteriosus (11.6%). Until now, four familial clusters were identified, representing a total of 13 patients.

CONCLUSIONS

This first epidemiological study of CHD in the Azorean population reveals evidence for familial aggregation, which is of great interest for understanding the genes involved in these complex pathologies.

Spread of heart diseases seen in an open-access paediatric echocardiography clinic

All patients <13 years of age referred to the open-access paediatric echocardiography clinic at the Sultan Qaboos University Hospital, Muscat, Oman, during the five years from 1994 to 1998 were analysed. Among the 2633 patients studied, 1543 (58.6%) were normal, 845 (32.1%) had congenital heart disease, and 245 (9.3%) had acquired heart disease. The major congenital heart diseases identified were secundum atrial septal defect (22.5%), ventricular septal defect (22.5%), patent ductus arteriosus (15.7%), mitral valve prolapse (10.7%), pulmonary stenosis (9.7%) and atrioventricular septal defect (4.5%). Fifty-eight percent of the congenital heart diseases were identified in the first year of life. Among the acquired heart diseases, rheumatic heart disease (30.2%) and cardiac involvement secondary to haemoglobinopathies (16.7%), dilated cardiomyopathy (16.3%) and hypertrophic cardiomyopathy (12.7%) were significant. Although the presence of specific cardiac symptoms was associated with a high yield of abnormalities, such disorders were also discovered in a significant number of children with isolated cardiac murmur. The referral source did not influence significantly the frequency of heart diseases diagnosed in this study. Open-access echocardiography is important in early detection of heart disease in the paediatric population.

Incidence and spectrum of congenital heart disease in Oman

We analysed the incidence and spectrum of congenital heart disease (CHD) in the Sultanate of Oman from 1994 to 1996. CHD was detected in 992 of 139,707 live births (incidence 7.1/1000 live births). The common CHDs were ventricular septal defect (24.9%), atrial septal defect (14.4%) and patent ductus arteriosus (10.3%). The frequency of atrioventricular septal defects (5.9%) was higher than reported from other countries. Age at diagnosis was under 1 month in 38% and 1-12 months in 40%. Cyanotic CHD was found in 21.7% of the whole group and 35% of neonates. Although this was a hospital-based study, we believe we included almost all the infants and children with CHD in the country. The incidence and pattern of CHD in Oman were similar to those reported from developed countries in Europe and America, except for a higher frequency of atrioventricular septal defects. The high prevalence of consanguinity in the country did not affect the overall incidence of CHD.

Pattern of congenital heart disease in the Southwestern region of Saudi Arabia

BACKGROUND

The aim of this study was to assess the frequency of various forms of congenital heart disease (CHD) among affected children in the Southwestern region of Saudi Arabia.

PATIENTS AND METHODS

During the study period (July 1994 to June 1996), 608 children were referred to Asir Central Hospital as having CHD. All the children were evaluated by a pediatric cardiologist and had electrocardiogram and echocardiogram.

RESULTS

Of the 608 patients, only 335, comprising 162 males and 173 females, had CHD. The male to female ratio was 0.9:1. The frequency of various forms of CHD was as follows: ventricular septal defect (VSD) 32.5%; patent ductus arteriosus 15.8%; atrial septal defect 10.4%; pulmonary stenosis 10.1%; atrioventricular septal defect and mitral valve prolapse, 3.6% each; aortic coarctation/interruption 3.3%; obstructive aortic valve lesions 2.7%; tetralogy of Fallot 4.5%; common ventricle 2.7%; pulmonary atresia (PA) with VSD 1.8%; D-transposition of the great arteries 1.5%; Ebstein anomaly 1.5%; and isolated PA 1.2%. Other lesions were extremely rare.

CONCLUSION

The distribution in this study is similar to that reported in previous studies from other parts of the world, except for the lower incidence of obstructive aortic valve lesions.

Incidence of congenital heart disease: I. Postnatal incidence

The incidence of congenital heart disease (CHD) in the Western industrialized world has varied from a low value of about 3 to 5 per 1000 live births to about 12 per 1000 live births. Most of the lower incidence figures were obtained before there were sufficiently well trained pediatric cardiologists and before the success of cardiac surgery put a premium on early and correct diagnosis of CHD. The advent of echocardiography with Doppler color flow measurements has made it possible to diagnose lesions that are asymptomatic, minor, and even without murmurs. Given these differences, there does not appear to have been a significant increase in the incidence of CHD over the last 20-30 years. The incidence of CHD in underdeveloped countries is not known, but the distribution of different lesions is fairly similar to those in developed countries except perhaps for fewer with aortic stenosis and coarctation of the aorta.

Congenital heart disease: incidence and inheritance

Congenital heart disease occurs in approximately 1 per cent of liveborn children, but in a much higher percentage of those aborted spontaneously or stillborn. To detect as many as possible with CHD, including those with mild lesions, very intensive studies are needed. Studies that are not so intensive, especially those done before modern diagnostic techniques were in general use, considerably underestimated the incidence of CHD in liveborn children. It appears that the incidence of CHD and of the various individual lesions does not differ in different countries or at different times, providing the ascertainment of CHD is complete and accurate. The commonest form of CHD is the ventricular septal defect, which occurs in 30 to 40 per cent of all children with CHD. The risks of recurrence in siblings and of transmission to future generations depends on the exact mode of inheritance involved. Approximately 5 to 8 per cent of CHD is due to gross chromosomal abnormalities, and the recurrence risk is that of the chromosomal derangement itself. Because many children with these chromosomal lesions die in infancy or have reduced fertility, the risk to future generations is relatively low. About 3 per cent of CHD is due to classical Mendelian gene effects, with correspondingly high recurrence risks in first-degree relatives. Most CHD has lower risks of recurrence and transmission than those predicted by Mendelian single-gene action. The popular explanation for their inheritance has been the interaction of polygenic effects and the environment, but recent studies of the recurrence and transmission risks of various forms of CHD do not fit this model well. The alternative model is a single gene defect modulated by random events. The recurrence risks for future siblings are 2 to 6 per cent, and for offspring are 1 to 10 per cent, but in a few families the recurrence and transmission risks may be much higher.

World survey of the common cardiac malformations: developmental error or genetic variant?

The common cardiac malformations are prevalent throughout the world, in countries of high technology and among the primitive races. These same malformations were described 200 years ago, ectopia cordis 5,000 years ago. Their recent increase is directly related to the advent of cardiac treatment. Most cardiac malformations known to man occur in the dog. The prevalence rate of these malformations is the same in the dog and in man (5-8/1,000). Several of the malformations are heritable in specific breeds of dogs, one in rabbits, another in rats. These malformations occur in various animals that cannot interbreed. Hence the deoxyribonucleic acid (DNA) that codes these malformations must lie in that portion of the DNA common to all mammals. This suggests that these malformations occurred during the evolution of the Mammalia. Mammals evolved from reptiles, animals with hearts of various structures for the separation of arterial and venous blood. Although the "normal" heart is the most compatible with mammalian life and hence the most common, some mammals may have evolved with a heart with different structures for the separation of arterial and venous blood. Some of these hearts have persisted. These primeval hearts we call cardiac malformations of the cyanotic group. Malformations that apparently are arrests in the development of the normal heart (patent ductus arteriosus, atrioventricular canal) may represent stages in the evolution of the "normal" heart. Although teratogens and mutagens do exist, the author conceives of congenital cardiac malformations not as arrests or errors in the development of a "normal" heart but as genetic variants.

Congenital heart disease in Nigeria: a ten-year experience at UCH, Ibadan

Of 880 patients who attended the paediatric cardiology unit, University College Hospital, Ibadan, during a ten-year period, 635 (72.2%) had congenital cardiac malformations. Ventricular septal defects were the commonest lesions (35% of the 635 cases), followed by patent ductus arteriosus (22%), Fallot's tetralogy (10%), pulmonary stenosis (9%) and atrial septal defects (7.5%). Coarctation of the aorta was uncommon (2%) and aortic stenosis rare (0.6%). The overall sex incidence was even. Aetiological factors were ascertained in 72 cases (11%). In 60% of these cases intra-uterine rubella was responsible and in 18% perinatal asphyxia. In most patients the cardiac malformation was detected late; consequently complications, such as heart failure, pulmonary hypertension, and polycythaemia were common, even in new patients. Sixty-seven patients (11%) died in hospital, mostly from surgical intervention, heart failure, hypoxaemia, bronchopneumonia and associated extracardiac defects. It is suspected that hypocalcaemia, resulting from vitamin D deficiency may be a cause of the observed low prevalence of obstructive aortic lesions. We suggest that cardiac evaluation be performed at birth in postnatal clinics and in immunization centres, in order to facilitate early detection and treatment of congenital heart disease.

Prevalence of congenital heart disease in black schoolchildren of Soweto, Johannesburg

A survey conducted by cardiologists in Soweto, Johannesburg, provided an opportunity of assessing the frequency of congenital heart disease in black schoolchildren. Among 12,050 schoolchildren aged 2 to 18 years, 48 had a congenital heart defect, yielding a prevalence of 3.9 per 1000. Only in 2- to 6-year-old children did the prevalence exceed that of rheumatic heart disease. The distribution of the types of defects was largely similar to that reported in other surveys with a predominance (52%) of ventricular septal defects. Two unusual findings were the unexplained absence of persistent ductus arteriosus in these children, and the detection of 5 children with situs inversus (1 in 2410). In all but one child, the congenital heart defect was first discovered during the survey. Despite the limitations of a prevalence study, it can be concluded that congenital heart disease is at least as common in this South African black community as in Caucasians.