Congenital heart anomaly is defined as structural abnormality of heart or adjacent great blood vessels present either at the time of birth or detected later in life while the acquired is triggered by insults on the heart after birth. The exact etiology is unknown but genetic and environmental factors tend to be implicated. Of cardiac diseases in childhood, congenital heart disease (CHD) occurs more frequently than acquired heart disease [7]. In developing countries, CHD is one of the non communicable diseases that cause mortality and morbidity in children.
The prevalence of congenital heart defect is 0.5-0.8% live birth and increases to 2-6% if first degree relative is affected. The prevalence of heart disease in general among children is 8 per 1000 live births. The prevalence of 0.22% obtained in our study is similar to that reported by Nelson et al. [8] who noted a prevalence rate of 2 and 10 per 1000 live births. The observed similarities in prevalence with studies that looked at populations not similar to ours could be due to the fact that both studies were done in a referral institution where major cardiac defects are seen.
Ejim and colleagues [10] evaluated the prevalence of ventricular septal defect (VSD) among patients referred for echocardiographic examination at the echocardiography laboratory of the University of Nigeria Teaching Hospital, Enugu, Nigeria over a 10-year period. They noted that of 2486 echocardiogram scans done; 593 subjects had congenital anomalies, of which 165 (prevalence of 0.28) had VSDs. This is also similar to our findings. From this study, there exists a male predominance when congenital heart disease is considered.
It is noted with interest, that most of the children with congenital cardiac anomaly were from very low socioeconomic background. Hemingway [11] and colleagues in his study also noted a strong association between low socioeconomic class and cardiac disease. The reason for this could be adduced from the fact that mothers from high socioeconomic class will seek corrective surgery abroad and as such may not report at local hospitals as against the low socioeconomic ones who cannot afford money for cardiac surgery.
The mean maternal age (in years) of those with cardiac anomaly is 32.3 ± 6. Grag [12] and colleagues also noted a high occurrence of congenital abnormality and other cardiac defects among women who are between 33 and 39 years of age. Other workers [12, 13] in their studies suggested that high pregnancy rates among mothers in this age range could account for the congenital abnormality.
Consanguineous marriage is an important factor that contributes to congenital cardiac disease among children. This is influenced by the degree of relatedness between the spouses such as first cousins, double first cousins and second cousins [14]. A consistent positive correlation has been reported between consanguinity and VSD, atrial septal defect (ASD), pulmonary atresia, tetralogy of Fallot and other CHDs in different populations [15]. We did not obtain any correlation between consanguinity and congenital heart disease in this study. Consanguinity, however, is not a common practice among the Igbos who are the indigenous and predominant inhabitants of Enugu and environs.
Isolated ventricular septal defect, with a frequency of 19.8%, was the most common defect in our study. This is lower than that reported in a recent study 41.59%, but higher than the frequency reported in another study [16, 17]. Factors such as method of diagnosis, non recognition of minimum or small septal defects by the physician responsible for primary care and poor hospital visits due to poverty and ignorance, may have contributed to the difference between our figures and those in the literature. With respect to cyanotic congenital heart defects, tetralogy of Fallot (8.5%), tricuspid atresia (4.2%) and total anomalous pulmonary venous drainage (1.4%) were the most frequent anomalies. According to the literature, the most prevalent anomaly is transposition of the great vessels, with an incidence ranging from 3.5 to 10.9% [18]. We recorded no case of TGA in our study, this is because death could have occurred before getting to a health facility and thus could not be accounted for. From this study, mothers of children with cardiac anomaly are relatively young, with very few taking local concoction and alcohol. The commonest local concoction taken by pregnant women in Nigeria contain aqueous bitter leaf, ginger, agbo, dogo yaro and cannabis[19]. Some of these herbal concoctions could cause deleterious effects in pregnancy. For instance Fischer-Rasmussen et al.[20] noted that ginger has been associated with mutagenesis in a culture of Escherichia coli (E.coli).
We could not conclude if there is any relationship between maternal intake of local concoction and congenital heart anomaly. Nevertheless, only three mothers took dogo yaro (a local concoction known to contain quinine) as a tonic to treat malaria during first trimester. Al-alni et al. [21] in his Saudi Arabia study noted no relationship between cardiac anomaly with maternal age and gender. This is in agreement with our study where sex ratios were equal.
It is important to note that VACTERAL associations and talipe deformities were seen in some children with congenital cardiac anomaly in our study. VACTERAL associations and talipe deformity have been reported in some children with cardiac anomaly by some workers [22]. Martinez-Frias et al. [23] in his work noted tetralogy of Fallot as the most common congenital heart defects seen in the VACTERAL association. It is noted in this present study that VSD and AVSD are associated with Down’s syndrome. This was corroborated by Paladini [24] and his workers who noted an incidence of 56% and 44% respectively among fetuses with AVSD and VSD, using amniocentesis and karyotyping. Dawson et al. [25] in a study had associated persistent left superior vena cava, coarctation of the aorta and partial anomalous pulmonary venous drainage with Turner’s syndrome. He also suggested jugular lymphatic obstruction in-utero, resulting in dilated lymphatic vessels around the aortic root, which may compress developing outflow structure as a cause of aortic deformation commonly seen in Turner’s syndrome.
It is disheartening to note that only a handful (6.2%) of children with congenital heart disease had surgery and a good number defaulted follow up. Treatment of children with CHD are limited to larger cities and it is quite expensive and beyond the reach of the poor. So many parents could not afford this cost and they will either abandon routine hospital visits or leave their children in the hands of fate.
To improve the survival of children with cardiac disease, there is need to diagnose and treat them at earliest age through provision of affordable diagnostic and surgical as well as other interventional facilities at each of the six geo-political zones of the country.
The main focus of investigation is 2-D echocardiography and ECG. Although trans thoracic echocardiography (TTE) with Doppler has been shown to be of great value in diagnosis of patients with Cor triatriatum; biplanar trans esophageal echocardiogram (TEE) provides a more complete and detailed data of the anatomy of cor triatriatum and other complex cardiac anomalies [26]. In this study, 2-D echocardiography, ECG and chest radiography to were used for the diagnosis of congenital cardiac anomaly.
Prenatal diagnosis may help detect this anomaly early and avert significant morbidity and numerous mortalities that follow this disease. Prenatal diagnosis has not to yet gained ground in the management of congenital cardiac disease in Nigeria.
Prenatal diagnosis allows for extensive parental counseling and coordination of care. The fetal diagnosis of CHD identifies chromosomal abnormalities, which are found in 10% of cases, and assesses associated extra cardiac anomalies, which coincide in 15% of cases [25]. In cases of poor prognosis, early prenatal diagnosis gives the parents the option of coming to a fully informed decision as to whether to continue with the pregnancy in some countries [12].
