Congenital heart defects (CHD) are the most common type of birth defect and the leading cause of infant deaths in the developed world. This implies a defect in the structure of the heart or blood vessels leading to or from the heart. The heart should have 4 chambers and 2 major vessels leading into the heart and two major vessels leading out of the heart. This includes mild defects such as Ventricular Septal Defects( VSD) while excluding defects associated with prematurity such as Patent Foramen Ovale(PFO) and patent ductusarteriosus (PDA)s. Critical congenital heart disease refers to a potentially life-threatening cardiac abnormality where either the systemic( blood to the body) or pulmonary( blood to the lungs) circulation is dependent on a PDA. These defects are present at birth but some are only recognised much later- weeks, months or even years later. The longer it takes to make the diagnosis , the more difficult the prognosis and in some cases, the more likely it is for surgery no longer to be an option.
Critical congenital heart disease manifests in the first few hours/days of life. They can either present with cyanosis or blueness. All babies have blue hands and feet at birth but this should improve and never be associated with a blue tongue or blue lips. This is an important danger sign and should never be ignored. If the blood is obstructed going to the body, the baby may first present with a fast heart beat, fast breathing, clod hands and feet and poor pulses to feel. An abnormal murmur may be not always be present.
Later on, babies who have intermittent blueness of the lips and tongue , again fast breathing and heart beats are concerning as well as those who tire or sweat with feeding. Although many children can have short murmurs, murmurs that are loud or associated with an enlarged heart or any symptoms must be referred to a cardiologist.
One suggestion has been to increase the surveillance immediately after birth using pulse-oximetry screening. Pulse oximetry has been used within clinical practice for some time and is a widely accepted method of assessing oxygen saturation. Critical congenital heart disease refers to a potentially life-threatening cardiac abnormality where either the systemic or pulmonary circulation is dependent on a patent ductusarteriosus. In both of these situations, abnormally low saturations on the foot and hand or a differential of >3% between the two readings should alert the clinician to possible cardiac anomalies. Pulse oximetry is a safe, feasible, easy test which is also cost-effective, has been shown to be acceptable to parents and medical staff alike and is unprecedented as a screening test to detect CCHD. However implementation necessitates integration into existing newborn screening programmes with commitment to training, sustainability and strengthening of collaborating healthcare infrastructure. The optimal programme for early detection, follow-up and data management in existing programs must be developed while CCHD screening must be integrated with current birthing services, ideally with centralized data management and quality control.
Acute rheumatic fever (ARF) is a serious illness which occurs mainly in children between the ages of 5 and 15 and results in Rheumatic Heart Disease (RHD) in up to 3% of untreated cases. In SA, RHD is the leading cause of acquired heart disease in children and young adults. Together, RF & RHD affect about 15.6 million people worldwide, 2.4 million of whom are children between five and fourteen years old in developing countries. ARF is an illness which thrives in poverty-stricken and developing countries especially in overcrowded, low-income areas, where housing conditions, nutrition, sanitation and health services are inadequate.
ARF is caused by an untreated sore ‘strep’ throat, which may lead to repeated attacks affecting the joints (arthritis), skin (rash) and heart (carditis). After attacks of untreated ARF, chronic heart valve damage (RHD) may develop. In the instance of RHD, open-heart surgery is necessary to repair or replace heart valves.
In developing countries, The World Health Organisation has recognised ARF as being a major problem, where approximately 100-200 per 100,000 school-aged children are affected. 2 Sadly, ARF and RHD are the most common cause of acquired heart disease affecting children and young adults worldwide.
It is not possible to accurately estimate the prevalence of Rheumatic Fever (RF) and Rheumatic Heart Diseases (RHD) in South Africa. A study showed that there is significant under-reporting of RF cases by health care professionals at hospital, municipal and provincial level. Lack of incidence reporting itself, is a direct result of a widespread lack of awareness among healthcare workers of the national guiding principles on RF/RHD which were released by the National Department of Health in 1997.
However, like any other developing country the general consensus among South African cardiologists is that the incidence of RF remains quite high in South Africa. This is supported by research showing that Rheumatic Heart Disease (RHD) is still the leading cause of acquired heart disease in children and young adults in South Africa.
Rheumatic fever is not an infection in and of itself. Rather, it is the consequence of an earlier infection of the throat by a specific organism, streptococcus which has been left untreated. RF generallymanifests around 3-6 weeks following the strep infection. Current estimates show that approximately 18% of all throat infections are caused by strep. This infection is infectious of course, and is especially prevalent in areas of poverty given the overcrowding, etc. Given the lack of access to care, many patients are thus not given penicillin and it is in a percentage of these persons that RF occurs.
Without intervention, patients who progress to RHD will require surgical intervention including heart valve repair, or replacement. The rate of success of heart valve replacement is currently 50%. In other words, 50% of people who undergo heart valves replacement surgery do not succeed. Furthermore, young patients will often need repeated valve surgery as they grow older and the body changes.
Given that prophylactic penicillin is the key element to prevent progression of the disease, teaching people about the importance of adhering to secondary prophylaxis will go a long way in ensuring:
The incidence of CHD is 1:100-1:150 while the figure of 8:1000 is the most widely generally accepted. This number is the same the world over. However in countries where antenatal screening ( usedfetal ultrasound) is not universal such as South Africa with varying rates depending on public/private/rural settings, the number is more likely to be higher. In addition certain factors can increase the incidence of congenital heart defects such as inadequate rubella over for mothers leading to congenital heart defects in the baby. We also know that based on these figures, we should be seeing far more children each year with certain critical congenital lesions and thus we are convinced that many children with congenital heart disease are missed and most likely die before a diagnosis is made. Other present too advanced for curative management. IN south Africa we have a dire need of paediatric cardiologist and qualified cardiac surgeons with less than 30 in the country. International figures state that we should have at least 88 paediatric cardiologists instead of our current 23. This is one of the reasons why we believe so many children are missed coupled with the poor rate of antenatal screening, late booking and early discharge. There are also reduced awareness generally about the fact that cardiac defects are common and that post-natal screening and 6 week checks are extremely important, as well as not ignoring any of the signs mentioned below.
Much can be done. Virtually every heart condition can be relieved, some entirely, by surgery. Some lesions may not even need surgery but catheter intervention or medication only. However delaying the diagnosis, can result in severe consequences. IN the past 50 years, the progress made in the treatment of congenital heart disease has been remarkable with mortality rates down universally below 5% in tertiary units and a very good chance of post-surgery children surviving into their late adulthood. IN fact in the US, more people are living with repaired congenital heart disease than are being born with it. However we are still a long way off this in south Africa. Although our mortality rates within hospitals are comparable with the world, due to excellent surgeons in this country, we know we are still missing many patients and many patients still present to us in extremis or too late for surgical options.
Until infants born in developing countries have access to comprehensive primary healthcare services, including antenatal assessment, qualified birth attendance and post-natal examination and only if cardiac services have improved concurrently in many of the regions under discussion, pulseox screening will not change the undeniable fact that infants with critical congenital heart disease will continue to be missed and die, many undiagnosed.