Congenital heart defects (CHDs) represent one of the most critical diagnostic challenges in perinatal medicine. Affecting approximately 10 in 1,000 live births and accounting for nearly one-fourth of all congenital malformations, CHDs contribute to 10% of infant mortality worldwide¹. They account for a significant share of infant morbidity and mortality, often due to delayed or missed diagnosis. This National Congenital Heart Defect Awareness Month, the spotlight turns to a critical truth: early detection of CHDs saves lives.

CHDs often present a diagnostic challenge because clinical symptoms may be subtle or delayed. Without early identification, newborns are at risk of rapid deterioration once fetal circulation transitions after birth. In this context, diagnostics are not simply supportive tools; they are critical enablers of early intervention and improved outcomes.

Causes and Risk Factors

The exact cause of CHDs is often unknown, but several factors may contribute:

1. Genetic Factors

• Genetic conditions like Down syndrome or Turner syndrome.
• CHO recurring in family is very rare.

2. Environmental Factors

• Maternal illnesses during pregnancy (e.g., rubella or diabetes).
• Certain medications or exposure to harmful substances.
• Smoking, alcohol consumption, or drug use during pregnancy.

Symptoms of Congenital Heart Defects

The symptoms of CHDs vary depending on the severity of the defect. Common signs to look out for include:

• Rapid or labored breathing.
• Cyanosis (bluish tint to the skin, lips, or nails).
• Poor feeding or difficulty gaining weight.
• Fatigue, especially during feeding or physical activity.
• Heart murmurs (unusual sounds heard during a heartbeat).

Diagnosis of Congenital Heart Defects

Diagnosing CHDs early is crucial for effective management. Modern medical techniques have made it possible to detect many defects before or shortly after birth.

1. Prenatal Diagnosis

• Fetal Echocardiogram: Uses ultrasound to assess the structure and function of the fetal heart, typically performed after 18 weeks.

2. Postnatal Diagnosis

• Physical Examination: Listening for heart murmurs and checking for signs of cyanosis.
• Echocardiography: A key diagnostic tool that provides detailed images of the heart’s structure and function.
• Chest X-rays: To evaluate the size and shape of the heart.
• Electrocardiogram (ECG): Assesses the heart’s electrical activity.
• Cardiac Catheterization: A more invasive procedure to diagnose complex defects and plan interventions

Blood tests and the child’s heart

Blood tests to evaluate heart disease

Children may have blood tests to help their health care provider evaluate their illness, or to help keep track of their health after surgery.

These tests may include:

• Complete blood count. This test measures the size, number, and maturity of different blood cells in the blood. These are red blood cells, white blood cells, and platelets.
  • Red blood cells are important because they carry oxygen through the blood to the organs and cells of the body. If your child doesn't have enough red blood cells to carry the oxygen their body needs, they may have anemia.
  • White blood cells multiply when your child has inflammation or an infection.
  • Platelets help the blood clot. This helps stop bleeding from cuts, for example.
• Electrolytes. This test measures minerals in the blood that are needed for your child's organs to work as they should. Minerals include sodium, potassium, calcium, and magnesium. If a child is taking water pills (diuretics), the medicine may cause electrolyte problems. Potassium levels are especially important for healthy heart function.
• BNP. This test measures how much BNP hormone is in your child’s blood. BNP stands for B-type natriuretic peptide. The heart’s pumping chambers (ventricles) make BNP. When the heart is working well, there are low levels of BNP in the blood. When the heart has to pump harder than usual, BNP levels are higher. BNP testing can tell if your child has a problem with the heart or lungs.
• Total protein and albumin. These tests can help evaluate a child's nutrition and how well the liver is working.
• Prothrombin time (PT), partial thromboplastin time (PTT), and international normalized ratio (INR). These look at how well the blood clots. Sometimes these tests are done to check how well blood-thinning medicines (anticoagulants) are working. Or to see if there is a risk of bleeding. These medicines are taken for various heart problems.
• Blood gas. A blood sample is taken from an artery to measure the amounts of oxygen and carbon dioxide in the blood. The acidity (pH) of the blood is also measured. This test may be done after pulse oximetry. This is a painless, noninvasive test. It measures the amount of oxygen in the blood through a small, infrared sensor placed on a child's finger, toe, or earlobe.
• Troponin. Cardiac troponin I and troponin T are sensitive biomarkers. Troponin is found in cells in your heart muscle. When these cells are injured, they can release troponin and other substances into the blood. Higher troponin levels may mean there's a problem with the heart.

Early detection saves lives, and diagnostics make early detection possible. From prenatal risk assessment to newborn screening, IVDs help clinicians act sooner, plan better and deliver care when it matters most.

Reference:

1. Jain, Pradeep & Lazarus, Monica & Tiwari, Asha & Athwani, Vivek Kumar. (2022). Prevalence and Pattern of Congenital Heart Disease in Pediatric Population—A Study from Central India. International Journal of Recent Surgical and Medical Sciences. 09. 10.1055/s-0042-1751085.