Structural heart diseases refer to a spectrum of cardiovascular diseases that involve a defect or disruption in the heart tissues or valves. They can be congenital (present at birth) or acquired (develop later in life). Regardless of the type, structural heart diseases are preventable for the most part. In today’s article, we shall highlight why.
Any defect or disorder in the structure of the heart muscles or valves results in structural heart diseases. Such defects may be thickening of the valves that lead to narrowing, for example, aortic valve stenosis. Or the valves weaken, allowing backflow of blood within the heart chambers, for example, mitral valve regurgitation. In another fashion, one or more valves mangle – one valve thickens, the other weakens – constituting valvular heart disease, a common finding in rheumatic heart disease. At times, one of the heart chambers stiffens due to increasing resistance to blood outflow: it undergoes hypertrophy: it loses the ability to pump out blood well enough – for example, in left ventricular hypertrophy. In a few instances, viruses attack the heart muscle and cause inflammation – myocarditis. A common connective tissue disorder – Marfan syndrome – can weaken the aorta and a bulge forms within its layers called an aneurysm. Not uncommonly, though, a significant portion of the heart stiffens and enlarges – the changes we call cardiomyopathy.
Most heart defects are congenital: they may include holes in either the upper or lower heart chambers – atrial and ventricular septal defects, respectively. Or a flaw in one of the blood vessels persists after birth. Other congenital heart diseases include patent ductus arteriosus, tetralogy of Fallot, transposition of the aorta, et cetera. Some are compatible with life; others are not. However, most of them require surgery to improve the quality of life of the affected people.
Congenital heart diseases are present everywhere around the globe. High-income countries have taken significant strides to improve the quality of life of such people through state-of-the-art surgeries and post-surgical care. Unfortunately, such endeavours are still lacking on the other side of the world – the low- and middle-income countries. Affected children and adults can hardly access such operations. The health care systems are either too poor to support them: or there’s no political will to drive the nations’ resources towards infrastructure development to equip the health care sector with the necessary capabilities to render the much-needed services. In a few countries where services exist, they are costly for the vulnerable population to afford. In other regions, the inhabitants often rely on donor funds to thrive, which are always not enough.
Most congenital heart diseases are preventable through high-quality antenatal services. Simple endeavours such as folic acid and vitamin B12 supplementation to disease prevention can suffice. A few of the conditions associated with congenital heart disease, like rubella, are preventable through immunisation. Others, through screening and behavioural changes.
On the other hand, most acquired structural heart diseases, especially rheumatic heart disease and Chagas, are common. They are prevalent in the impoverished regions of the world like sub-Saharan Africa and South America.
Rheumatic heart disease affects the heart valves. It results from pharyngitis (sore throat) that goes untreated. To date, it takes a significant portion among the causes of acquired heart diseases in children and adults in low- and middle-income countries. It damages the valves and leads to valvular heart disease: a precursor for heart failure. Poverty remains the most crucial risk factor for rheumatic heart disease. Overcrowding, undernutrition, low education status, especially for mothers, and unemployment are associated with poverty. Prevention strategies include vaccination against group A streptococcal bacteria, timely management of acute rheumatic fever with appropriate antibiotics, and preventing recurrence. Parents of children with sore throats must seek medical attention and treat them if investigations show bacteria as the source of infection. Most sore throats are due to viruses, but we cannot tell unless we investigate them. Economic empowerment is key to driving people out of poverty: such that they can access basic human needs like proper housing conditions, clean water, and food. Awareness about the safety of vaccines should be a top priority within society to prevent all vaccine-preventable diseases. Avail penicillin antibiotic at all health centre levels to enhance primary and secondary prevention.
Chagas disease is prevalent in Latin American and Caribbean countries; however, migration has made a public health threat to the inhabitants of North America and other nonendemic regions. A disease caused by a protozoon (Trypanosoma cruzi) leads to cardiomyopathy after a prolonged period of no treatment. The resultant complications may include abnormal heart rhythm and sudden death. The parasite causing the disease is easily controllable through deliberate vector control programs, yet, it is still a burden among the tropical diseases, only third after malaria and schistosomiasis. Spraying with insecticides, improving housing conditions, and education remain the most significant ways of reducing the disease burden.
In a nutshell, structural heart diseases are either congenital or acquired. Whereas congenital ones are prevalent globally, most acquired structural heart diseases are endemic to impoverished regions. Besides, most congenital heart diseases are amenable to surgical interventions, yet these aren’t readily available in low- and middle-income countries. Rheumatic heart disease and Chagas disease constitute a substantial burden of structural heart diseases, yet, they are preventable for the most part through simple but deliberate interventions like driving people out of poverty through consistent endeavours. When people are no longer poor, their sanitation, housing conditions, feeding, and health-seeking behaviours improve. Some congenital heart diseases are also preventable through enhancing high-quality antenatal care, a policy that we are yet to achieve in most of the low- and middle-income countries.
For further analysis of structural heart diseases, read Dr David A. Watkins’ article from here.