Nigerian Journal of Cardiology

: 2021  |  Volume : 18  |  Issue : 2  |  Page : 35--43

Cardiac disease and associated comorbidities seen among children in Niger Delta region of Nigeria during a cardiac screening program

Queennette Obby Daniels1, Frances Sam Okpokowuruk2, Chika O Duru3, Olukemi O Ige4, Efe E Abolodje5, Patience A Udo2, Christopher S Yilgwan4, Olawale Olabiyi6,  
1 Department of Paediatrics, Federal Medical Center, Keffi, Nigeria
2 Department of Paediatrics, University of Uyo Teaching Hospital, Uyo, Nigeria
3 Department of Paediatrics, Niger Delta University Teaching Hospital, Okolobiri, Bayelsa State, Nigeria
4 Department of Paediatrics, Jos University Teaching Hospital, Jos, Plateau State, Nigeria
5 Department of Paediatrics, Delta State University Teaching Hospital, Oghara, Delta State, Nigeria
6 Pediatric Cardiology Associates, Methodist Children's Hospital, San Antonio, Texas, USA

Correspondence Address:
Dr. Queennette Obby Daniels
Department of Paediatrics, Federal Medical Center, Keffi, PMB 1004, Nasarawa


Background: There are few studies on the pattern of cardiac diseases (CD) among children in the Niger Delta region of Nigeria. This study examines the pattern of cardiac disease and associated comorbidities among children living in the Niger Delta region of Nigeria during a cardiac mission. Materials and Methods: This was a descriptive cross-sectional study which involved all children with prior diagnosis of CD referred from all the states of Niger Delta region of Nigeria. All children had echocardiogram and electrocardiogram performed by a team of Paediatric cardiologists. Results: Out of a total of 155 children who presented for the cardiac screening exercise, 145 (75 males and 70 females) children had CD. Their ages ranged from 0.2 to 180 months with a mean age of 45.5 ± 44.3 months which was significantly higher than their mean age at first diagnosis of 12.2 ± 22.9 months (P = 0.0072). Of the 145 children with cardiac disease, 128 (88.3%) of the patients had congenital heart disease and 17 (11.7%) had acquired heart disease and arrhythmias. Ventricular septal defect, Tetralogy of Fallot, and Rheumatic heart disease were the commonest acyanotic, cyanotic and acquired heart diseases respectively. Solitary lesions accounted for 91 (62.8%) of cases while multiple lesions accounted for 54 (37.2%) with as many as 35 (24.1%) children having complex heart diseases. Sixty-nine (47.6%) children presented with comorbidity. Conclusion: The burden of cardiac disease and complex heart disease in the Niger Delta region of Nigeria remains high. Early detection and prompt intervention would help to reduce the morbidity.

How to cite this article:
Daniels QO, Okpokowuruk FS, Duru CO, Ige OO, Abolodje EE, Udo PA, Yilgwan CS, Olabiyi O. Cardiac disease and associated comorbidities seen among children in Niger Delta region of Nigeria during a cardiac screening program.Nig J Cardiol 2021;18:35-43

How to cite this URL:
Daniels QO, Okpokowuruk FS, Duru CO, Ige OO, Abolodje EE, Udo PA, Yilgwan CS, Olabiyi O. Cardiac disease and associated comorbidities seen among children in Niger Delta region of Nigeria during a cardiac screening program. Nig J Cardiol [serial online] 2021 [cited 2023 Feb 6 ];18:35-43
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Full Text


Cardiac diseases (CD) are diseases of the heart and or its great vessels. They are classified as either congenital heart disease (CHD) or acquired heart disease (AHD). CHD is defined as an abnormality in the cardio-circulatory structure or function which is present at birth or detected later on while AHD is a heterogeneous group of disorders that arise from damage to the heart and blood vessels by a variety of pathological processes and appear in an individual after birth.[1],[2] Although considerable controversy exists regarding the definition, classification, and nomenclature of various forms of complex heart anomalies,[3] they are considered as a set of malformations often associated with complex alterations in hemodynamics.[4],[5] The epidemiological patterns of CD differ greatly between the developed nations and sub-Saharan Africa, where it is a major contributor to childhood morbidity and mortality.[6],[7] In Nigeria, studies from the different regions of the country have documented the various pattern of CD seen among children in their various regions.[8],[9] CHD is known to be the most prevalent form of CD among children. Globally, the incidence of CHD ranges from 4 to 12 per 1000 live births.[10],[11] In Nigeria, the incidence of CHD is from 3.5 to 9.3 per 1000 live births.[12],[13] While the overall incidence of childhood AHD in Nigeria and other developing countries is not fully known, a prevalence of 28.8% to 68% has been reported.[14],[15],[16]

Cardiac disease can be life-threatening in early childhood and children born with complex/severe forms are at approximately 12 times higher risk of mortality in early life.[17],[18] Unlike developed countries, diagnosis in low- and middle-income countries is often delayed and many patients die early without any opportunity for surgical intervention due to inadequate health care system.[19] In Nigeria, very few centers are equipped for open-heart surgery and majority of defects selected for surgical repair are simple defects.[20]

The Niger Delta region of Nigeria, comprising of nine states, are the oil-producing states in Nigeria. The region constitutes 25% of the Nigerian population and is known to make Nigeria very popular for her huge crude oil deposits.[21] Increased risk of CD in this region has been thought to be due to environmental degradation and industrial pollution secondary to petroleum mining and gas flaring in the region.[22] The studies on CD among children in the Niger Delta region of Nigeria have largely been reports from individual hospitals.[18],[22] This study aims at examining the pattern of CD and associated comorbidities among children in Niger Delta region of Nigeria seen during a cardiac screening program on referral from different hospitals in the region.

 Materials and Methods

This was a cross-sectional study conducted at Uyo, Akwa-Ibom state during a cardiac mission exercise in May 2019 which was sponsored by an NGO. This cardiac screening exercise was done in preparation for cardiac surgery which was done for some of the patients at a later date. General pediatricians and pediatric cardiologists in private and government hospitals in the Niger Delta states of Nigeria were informed via written communications and various social media platforms 6 months prior to the date of the exercise to refer known patients with congenital and acquired heart disease for free cardiac screening. The screening spanned over a period of 1 week. The study was approved by the Research and Ethics Committee of the University of Uyo teaching hospital, Uyo, Akwa-Ibom State.

All the children who presented for the screening were grouped into five major groups (Akwa-Ibom, Cross-river, Rivers/Imo/Abia, Delta/Edo/Ondo and Bayelsa) based on their state of residence over the last 1 year prior to referral. A semi-structured interviewer-administered questionnaire was filled out for all the children and included sociodemographic information of the parents, maternal antenatal, birth and drug history, and risk factors for congenital or acquired heart diseases. Comorbidities and complications were also noted. Abnormal dysmorphic features identifying common syndromes like Down's or Congenital Rubella were also noted and documented. The children's present age, age at first diagnosis, and sex were noted. The socioeconomic class was determined using the methods described by Oyedeji.[23] The children body weights were measured using a bassinet weighing scale for infants and a calibrated weighing scale for older children, using standard methods measured to the nearest 0.1 kg.[24] The heights of the children were taken using a stadiometer to the nearest 0.1 cm while those <2 years old had their lengths taken with nonelastic tape rule.[24] Wasting was assessed using the World Health Organization growth chart for children 0–59 months while the Center for Disease Control growth chart (2–20 years) was used for children above 59 months.[25],[26]

Each child was physically examined and evaluated with electrocardiogram (ECG) and echocardiogram (ECHO). The ECG was performed by a research assistant who had been properly trained on appropriate ECG lead placement using GE MAC 600 machine, standardized at a paper speed of 25 mm/s and later read by a Paediatric cardiologist. Echocardiography was done using GE vivid IQ and GE vivid E machines by four trained Paediatric cardiologists who were paired in each screening room and the lead United States-based pediatric cardiologist who oversaw the screening process. Each ECHO was obtained using the segmental systematic approach with an average of 30–35 studies being performed daily. All ECHOs were thereafter evaluated by the entire cardiology team before a conclusive diagnosis was reached. The diagnosis and classification of cardiac malformation were determined according to the recommendations of the American Society of Echocardiography.[27] However, the types of complex CHD were gotten from those already documented in literatures.[5],[18],[28] The presence of pulmonary hypertension was determined using the tricuspid regurgitant jet pressure gradient and the right atrial pressure, right ventricular hypertrophy, and dilated main pulmonary artery (PA).[29] The possible known risk factors for CD were identified from the structured questionnaire and together with the use of phenotypical features and maternal history in the cases of Down's and Congenital Rubella syndromes, respectively.

Statistical analysis

The data were coded and analyzed using IBM SPSS Statistics for Windows, version 22 (IBM Corp., Armonk, N.Y., USA). The pattern and frequencies of CD were presented as simple percentages. The level of statistical significance was P ≤ 0.05.


General characteristics

One hundred and fifty-four patients presented for the screening exercise of which 145 children were found with cardiac disease, 7 had spontaneously closed defects (as determined by comparing previous ECHO reports), 2 had recent repair of their defects and came for follow-up ECHO. Most of the children were from Akwa Ibom (44.1%), Rivers (24.8%) and Delta (18.6%) states of the Niger Delta region. Of the 145 children with cardiac disease, 75 (51.7%) were males and 70 (48.3%) were females in a ratio of 1:1.07. Majority 62 (42.8%) of the children were aged between 1 and 5 years, 45 (31.0%) were aged between 1 month and 1 year, and 37 (25.5%) above 5 years. The only neonate (0.7%) aged 5 days was delivered during the screening period at the host hospital. The mean age of children with CD at presentation for the screening was 45.5 ± 44.3 months (range 0.2–180 months) and this was significantly higher than the mean age at first diagnosis (12.2 ± 22.9 months; range 0–84 months; P = 0.0072). Majority 79 (54.5%) of the parents of these children were from the upper socioeconomic class while 44 (30.3%) and 22 (15.2%) were from the middle and low classes, respectively [Table 1]. The possible known risk factors associated with CD that were observed in this study were chronic and adverse maternal illness 47 (32.4%), Down syndrome 35 (24.1%), prematurity 10 (6.9%), chronic ingestion of alcohol and herbal concoction 10 (6.9%), other congenital anomalies 3 (2.1%), child obesity 3 (2.1%), assisted reproductive technology 3 (2.1%), HIV 2 (1.4%), sickle cell anemia 1 (0.7%), and congenital Rubella syndrome 1 (0.7). There were cases in which multiple risk factors were identified.{Table 1}

Cardiac disease

A total of 128 (88.3%) children had CHD while 17 (11.7%) had AHD. Majority 91 (62.8%) had single or solitary cardiac disease; of which 78 (85.7%) had CHD and 13 (14.3%) had AHD, the remaining 54 (37.2%) had multiple cardiac diseases with majority being a combination of more than one CHD (mixed CHD), three children had a combination of CHD and AHD and only one child had mixed AHD. The children with acyanotic CHD had a mean age of 42.2 ± 42.7 months at presentation but this was not significantly different from children with cyanotic CHD (41.6 ± 39.7) and AHD (73.3 ± 39.9) months; P = 0.213.

Congenital heart disease

Of the 128 children with CHD, 91 (62.8%) were acyanotic and 37 (25.5%) were cyanotic. The commonest acyanotic CHD was VSD accounting for 58 (63.7%) and contributing 45.3% of all CHD. In the acyanotic group, 63 children had solitary lesions with solitary VSD accounting for 28.6%, solitary ASD for 13.2%, and solitary patent ductus arteriosus (PDA) for 12.1%. Atrioventricular septal defect (AVSD) was seen in 10 (11%) patients and majority (80%) of them seen in children with Down's syndrome. The only child with Congenital Rubella syndrome had a PDA. Other solitary lesions are shown in [Table 2]. [Table 3] shows the pattern of multiple defects seen in this study. The most common cyanotic CHD (CCHD) was Tetralogy of Fallot (TOF) accounting for 17 (45.9%) of CCHD and contributing to 13.3% of all CHD. Two TOF patients had associated ASD (pentalogy of Fallot) while another two had “pink” TOF with oxygen saturations of 94%–96%. There were 5 (13.5%) Transposition of the great arteries, 4 (10.8%) truncus arteriosus and 3 (8.1%) double outlet right ventricle (DORV). The most CCHD presented with complex heart lesions.{Table 2}{Table 3}

Complex congenital heart disease

There were 35 (24.1%) children with complex CHD with a mean age of 48.3 ± 47.5 months (range: 0.08–14 years). There were 22 males and 13 females (male: female = 1:1.7). Amongst the complex CHD, were 7 (20%) children with severe TOF with pulmonary atresia of which 3 of them had multiple aortopulmonary collaterals (MAPCAs) and one had associated double superior vena cava (SVC) and hypoplastic left ventricle (LV). Three (8.6%) children had dextrocardia and DORV in various combination with other CHD respectively, two (5.7%) cases both males with ages 4 months and 6 years respectively had Taussig–Bing anomaly, which is characterized by transposed great arteries, large subpulmonary VSD, semilunar valves at same height lying side by side, subaortic and subpulmonary conal free wall with absent pulmonary-mitral continuity [Figure 1]. Two (5.7%) cases of single ventricle morphology and hypoplastic left heart syndrome respectively, a case of heterotaxy with transposed great arteries, pulmonary veins draining into coronary sinus and single ventricle morphology, and a case of mixed type of total anomalous pulmonary venous return with ASD, VSD and dilated coronary sinus. The mixed TAPVC was a combination of anomalous connection at the supra-cardiac level and at the infra-cardiac level. [Table 4] shows the pattern of complex CHD.{Figure 1}{Table 4}

Acquired heart disease and arrhythmias

Rheumatic heart disease (RHD) was the commonest AHD accounting for 8 (47.1%) of the children with AHD and contributing to 5.5% of all CD. The mean age (95.5 ± 25.5 months; range 4.75–10 years) of children with RHD were significantly older than other children with AHD (P = 0.001). Two children with RHD had an associated inlet VSD. Other AHD was pericardial disease/effusion in 4 (23.5%) children with two of them occurring among Down syndrome children who also had hypothyroidism and one had pericardial effusion complicating RHD and 2 (11.8%) had primary systemic hypertension in an 8 years old obese girl and an infant. The only arrhythmias noted was in 3 (17.6%) children with supraventricular tachycardia and structurally normal heart.

Associated co-morbidities and complications

Sixty-nine patients (47.6%) presented with co-morbidity with the most common being delayed developmental motor milestones noted in 48 of them. Others were severe wasting in 15, noncardiac congenital anomaly in 5, which included cleft palate, cleft lip, and unrepaired omphalocele, and cerebral palsy in a 7-year-old child with congenital rubella syndrome respectively [Figure 2]. The major complications noted were congestive heart failure (HF) in 50 (34.5%) and pulmonary hypertension in 20 (13.8%) children, respectively.{Figure 2}

Access to intervention

Only two children had surgical intervention; one was a 3-year-old male child with Down's syndrome with AVSD/severe pulmonary hypertension who had a PA band at 1 year of age in India and the other was a 3 year-old-female child who had her TOF repaired in India about a month prior to the screening.


The spectrum of cardiac disease seen in this study is similar to what has been documented in the literature with CHD being the most prevalent and VSD, TOF, and RHD being the commonest acyanotic, cyanotic CHD, and AHD respectively.[6],[30] Although recent studies in the western region of Nigeria have reported RHD prevalence as being on the decline,[15],[31] this is not the case with the northern region of the country[16] and surprisingly not the case in this study. Finding a high proportion of RHD among the children with acquired heart diseases may be related with the poor socioeconomic conditions of the Niger Delta region where decades of oil exploration and neglect have adversely affected the region. RHD is a disease of poverty and overcrowding. It is usually found among populations that are poor, neglected, or disadvantaged in many social amenities.[31] This is supported by evidence showing the decline of RHD in populations that have had improvement in primary health care services as well as the establishment of both primary and secondary prevention of the disease.[31] Despite the reported decline, the proportion of children and young adolescents with RHD is still relatively high.[14],[15],[16]

CHDs were prevalent in our study which is not surprising as they are the most common types of CD in children. Otaigbe and Tabansi[22] who reported on CHDs in a hospital-based study in Port Harcourt; one of the states in the Niger Delta region attributed the high prevalence of CHD in the area to environmental factors. The Niger Delta states are oil-rich cities where crude oil exploration is rampant with oil spillage which is known to commonly affect water quality and terrestrial fauna. Gas flaring which is also very common constitutes toxic threats to inhabitants. Inhalation of heavy hydrocarbons, affectation of vegetation grown for consumption with toxic agents from environmental pollution can become toxic to the body over time and may induce malformation in the fetus during the early weeks of organogenesis.[22],[32] Various studies from different states in the Niger Delta region of Nigeria have shown a high prevalence of congenital malformations affecting different systems of the body[33] so it is not surprising to see a similar high prevalence in cardiac disease amongst children from this region. These studies have all suggested pollution from petrochemical industry as a major predisposing factor,[33],[34] and this calls for more investigations and addressing the issue of petrochemical pollution in this region of the country.

The causes of CHD are rarely known in individual cases. However, about 5%–8% have associated chromosomal anomalies and 2%–4% are associated with environmental, adverse maternal conditions, and teratogenic influences.[35] In this study, chronic adverse maternal illnesses such as hypertension and diabetes, and chromosomal anomaly (Down's syndrome) constituted >50% of the identified risk factors associated with CD. These may also be attributed to the petrochemical hazard faced by people in this region especially as increased risks of structural birth defects and chromosomal abnormalities have been reported to be due to air pollution and proximity to environmental waste.[22],[33]

The cardiac disease continues to be a significant cause of morbidity and mortality in low- and middle-income countries. The coexistence of AHD and CHD is not uncommon.[36],[37] Mostly reported is the co-existence of RHD and various combinations of CHD which in some cases leads to early and severe pulmonary arterial hypertension (PAH) and HF.[36] In this study, we reported cases of RHD coexisting with an inlet VSD which were complicated with HF and PAH. This is not surprising as RHD, a late sequel of rheumatic fever due to immune-mediated damage to the cardiac valves, results in valvular incompetence and in the presence of a left to right shunt like VSD leads to pulmonary over circulation and hence the early occurrence of these complications.

The presence of complex and multiple CHD is not unexpected as this has been similarly reported from other Nigerian authors. Chinawa et al.[18] reported 0.05% from the eastern region of Nigeria while Sadoh et al.[28] reported 7.8% from the West and Federal capital territory though both studies were retrospective. A closely similar cross-sectional study in Pakistan reported only 3% of complex CHD but this study only involved children <5 years of age.[38] Otaigbe and Tabansi[22] in a prospective study in a Niger Delta state reported 27.3% of multiple CHD. Most of the previous studies were over a longer period unlike the present study which was conducted over a week in a screening program. However, the findings of a high proportion of complex and multiple defects in these children is worrisome and may be related to the teratogenic effect of gas flaring and oil spillage in the Niger Delta region.[22],[32],[34] Among the complex cardiac anomalies are very rare conditions, some of which had never been reported in any Nigerian studies. Taussig–Bing anomaly is a rare congenital malformation that was first described in 1949 by Helen Taussig and Richard J. Bing as consisting of transposition of the aorta to the right ventricle and malposition of the PA with subpulmonary VSD.[39] In this study, we reported two cases of this rare anomaly that has not been reported in any Nigerian setting, accounting for 1.6% and 1.4% of all the children with CHD and CD respectively. Both children were males, and none had any form of surgical intervention.

Another rare complex anomaly found was Heterotaxy syndrome occurring with transposed arteries and single ventricle morphology. Heterotaxy is a heterogeneous group of abnormalities where the internal thoracoabdominal organs demonstrate abnormal arrangement across the left-right axis of the body.[40] Its prevalence is said to be underestimated but higher in Asians than western world.

TOF was the most common cyanotic CHD, similar to that documented in most other studies in the country. However, unlike these other studies, not all TOF was included in the complex CHD in this study. Those included were associated with pulmonary atresia with either confluent or nonconfluent branched pulmonary arteries, presence, or absence of MAPCAs. Most of these children presented very sick with those without MAPCAs having saturation as low as 45%–50% while those with MAPCAs having a saturation of 70%–85%. Another anomaly noted was double SVC occurring with TOF and pulmonary atresia. Double SVC, a rare anomaly, is surgically important in the presence of CHD.[41]

Cardiac interventions, including surgery, was performed in only two children with CHD prior to the cardiac mission reflecting the limited access and high cost of appropriate cardiac interventions. In Nigeria, very few hospitals can undertake open heart surgery locally and most of such surgeries are during cardiac missions where mainly simple and low-risk cardiac patients benefit while few other patients through NGOs, state governments, and philanthropists get surgeries done abroad, hence the majority of children with cardiac disease are left without any form of intervention causing many to die early or live with the defects developing debilitating complications.[42]

In this study, 34.5% and 13.8% presented with complications of HF and pulmonary hypertension respectively. HF is a known complication of long-standing untreated CHD, and this has similarly been reported in other studies.[28],[43] Moderate and large intracardiac shunts in CHD often presents with HF as a result of increased pulmonary blood flow. HF is also known to complicate AHD such as pericardial disease and valvular incompetence from RHD.[44] Pulmonary hypertension was another complication noted in this study. Prolonged exposure of the pulmonary vascular bed to high pulmonary blood flow leads to the rapid development of PAH. Although most of these children were already on sildenafil, it is not clear if it was given to prevent or treat PAH. A study on the effect of early commencement of sildenafil in these children at risk of PAH is therefore important in our environment where open-heart surgery is not readily accessible or affordable.

Delayed developmental milestones (DDM) were the most common comorbidity in this study. Mussatto et al.[45] in their study noted that children with CHD were at high risk of developmental disorders, disabilities, or developmental delay including delayed achievements of developmental milestones. Complex CHD survivors are at greater risk for developmental issues compared to heart-healthy children, which may stem from the underlying heart defects, a genetic disorder, required medical therapies, or the psychological stress of living with a serious chronic disease.[46] In this study, over two-thirds of the children with complex congenital anomalies had DDMs. It is, therefore, necessary to institute timely and periodic developmental surveillance and evaluation for children with CHD for early detection and intervention.

Although more than half of the parents of the children were in the upper SEC in this study, we noted that the children had late diagnosis of their CD, with a mean age of first diagnosis of 12.2 months, and at the mean age of 45.5 months majority are yet to have surgical repair or intervention. It is evident that families from this region are still not able to afford pediatric cardiac services and open-heart surgery. A recent audit on the availability and distribution of Paediatric cardiology services and facilities in Nigeria shows a gross inadequacy and poor distribution of these services across the country.[20] It also noted that though the cost of cardiac surgeries in Nigeria is cheaper than most centers internationally, most families still cannot afford them. A viable health insurance scheme will help in decreasing the financial burden on families.

Our study is not without limitations. Our study involved patients who were pooled from several states, coming for a free cardiac screening with the aim of selecting some for surgical interventions might have resulted in some selection bias thereby potentially influencing the prevalence gotten. However, findings from this study will contribute to the database of the burden of the childhood cardiac disease in the Niger Delta region of Nigeria.


The burden of cardiac disease especially complex CHDs in the Niger Delta region of Nigeria appears to be high. Late diagnosis is still a scourge and most of our subjects in this study had no intervention and presented with complications. There is an urgent need to establish regional cardiac centers of excellence where these children can access early diagnostic and definitive care within Nigeria.


We are grateful to the Hospitals for Humanity – A non-governmental organization involved with cardiothoracic surgery initiative in Nigeria and Delta Afrik Charitable Foundation for their support in sponsoring the cardiac screening exercise.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.


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