Background: Down syndrome (Trisomy 21) is the most common chromosomal disorder associated with multiple congenital anomalies, among which congenital heart disease (CHD) is a major contributor to morbidity and mortality. The spectrum of CHD varies across populations, necessitating region-specific data. Aim: To study the spectrum and pattern of congenital heart disease in children with Down syndrome in a tertiary care hospital. Methods: This hospital-based observational study was conducted in the Department of Paediatrics in collaboration with Cardiology at Sree Mookambika Institute of Medical Sciences, Tamil Nadu, from January 2025 to December 2025. A total of 72 children clinically suspected of Down syndrome were evaluated and advised karyotyping. Sixty-five cases were confirmed as Trisomy 21 by G-banding technique, and all underwent echocardiographic evaluation. Children with confirmed congenital heart disease were included in the study. Clinical details, demographic profile, maternal age, extracardiac anomalies, and echocardiographic findings were recorded and analyzed using appropriate statistical methods. Results: Out of 65 karyotype-confirmed cases, 36 (55.4%) had congenital heart disease. Among these, 55.6% were males and 44.4% were females (M:F = 1.25:1). Majority of patients (55.6%) were diagnosed within the first 6 months of life. The highest proportion of affected children (41.7%) were born to mothers aged 30–35 years, although 50% of cases occurred in mothers below 30 years. Ventricular septal defect (25%) was the most common cardiac lesion, followed by atrial septal defect (22.2%) and patent ductus arteriosus (19.5%). Tetralogy of Fallot was seen in 5.5% of cases. Developmental delay was present in all children (100%), while recurrent respiratory tract infections (66.6%) and hypothyroidism (19.4%) were common associated conditions. Conclusion: Congenital heart disease is highly prevalent in children with Down syndrome, with septal defects being the most common. Early diagnosis through karyotyping and routine echocardiographic screening, along with comprehensive multidisciplinary care, is essential to improve clinical outcomes and quality of life.

Down syndrome, Trisomy 21, congenital heart disease, ventricular septal defect, echocardiography, maternal age.