Congenital Heart Disease (CHD) refers to heart conditions present at birth and each case tells its own unique story. These conditions range from simple holes between heart chambers (atrial septal defect) to complex cases where a patient may have only one ventricle (a main chamber of the heart) instead of the normal two. While some newborns appear blue (cyanosis), requiring urgent intervention, others might not show any symptoms until later in life. 

Singapore has seen an increase in CHD cases, from approximately 0.81% of total live births from 1994 to 2000 to 0.97% in 2021. Thanks to modern technology, survival rates have improved - more than 90% of these patients now live into adulthood, compared to just 25% fifty years ago. For many with complex CHD, their journey involves multiple surgeries and/or catheter interventions throughout their lives.

The 'hole in the heart' (atrial or ventricular septal defects) is a relatively straightforward type of CHD that can be treated surgically to close the 'hole'. However, timing is crucial. Left untreated, these defects can severely damage the heart and lungs. Blood meant for other parts of the body can escape to lungs through the defect, potentially causing permanent lung damage. At advanced stages, closing the 'hole' in the heart becomes impossible as it actually helps to relieve the pressure on the heart. These patients may ultimately require heart or lung transplantation. Early diagnosis is key – most cases can be treated with minimally invasive procedures before complications arise.

Patients with Tetralogy of Fallot have underdeveloped pulmonary valves (which regulate blood flow from the heart to the lungs) and ventricular septal defects, along with other heart lesions. These patients typically undergo complete surgical correction during childhood, which includes ventricular septal defect closure and relieving the obstruction caused by the underdeveloped pulmonary valve. However, the pulmonary valve often becomes leaky after the surgery, necessitating replacement when patients reached adulthood. Currently, patients who are not suitable for catheter-based replacement would be referred for surgical pulmonary valve replacement.

Diagnosing CHD involves detailed scans and tests like echocardiograms and cardiac imaging. These tests help the medical team to map out patients' unique heart structure and develop an appropriate treatment strategy. While some heart conditions can be managed with medications or minimally invasive procedures, others need surgery to help the heart work better. 

CHD encompasses an extremely wide variety of cardiac abnormalities. The general principles of management often involve staged procedures, as illustrated in Tetralogy of Fallot cases. Newborns with this condition often experience 'blue' spells due to their severely underdeveloped pulmonary valve limiting blood flow to the lungs. Since these infants are initially too small for complete corrective procedures, surgeons first perform Blalock-Taussig shunt (a surgical procedure to increase blood flow to the lungs) to stabilise their blood circulation and turn them 'pink'. This allows the baby to grow stronger until they are ready for full corrective surgery, typically between six months to one year of age.

The management of CHD demands seamless collaboration among cardiac surgeons, cardiologists, cardiac intensivists, and radiologists. After comprehensive testing to understand each patient's cardiac anatomy, the team determines the best strategy to secure adequate blood flow to the lungs. Treatment options include medication, catheter intervention or surgical procedures. However, given the complex and evolving nature of congenital heart conditions, many patients undergo multiple operations throughout their lives. These reoperations rank among the higher risk cardiothoracic surgical procedures and require meticulous planning. With various treatment approaches offering different advantages and challenges, all cases are carefully reviewed at weekly multidisciplinary team meetings to determine the most appropriate treatment strategy moving forward.

The Hospital for Sick Children in Toronto, ranked as the top paediatric hospital by Newsweek, and Toronto General Hospital, ranked third among global publicly-funded hospitals, are leading centres for congenital heart surgery serving patients across North America and internationally. During his two-year fellowship (2022-2024) at the institutions, Dr Yap Kok Hooi participated in a comprehensive range of congenital heart surgeries under the mentorship of world-renowned surgeons including Dr David Barron, Dr Osami Honjo, Dr John Coles, Dr Christoph Haller and Dr Rachel Vanderlaan. These include corrective and palliative surgeries in newborns, adult congenital heart procedures, minimally invasive surgical techniques, ventricular assist device implantation in children, and complex heart and lung transplants. He also spent some time in specialised observerships in lung transplant service, adult cardiac surgery, and paediatric thoracic surgery. The intensive training has enhanced his expertise in managing complex congenital heart and lung conditions across all age groups, bringing advanced surgical techniques to benefit patients in Singapore.

"In surgery, I often see these hearts - some no bigger than a strawberry in newborns. Each one represents their owner's unique journey. A surgeon's mission is to provide the best possible care for these hearts, working to change lives one surgery at a time."