Congenital heart disease in Malta

Abstract

Introduction Congenital malformations are important causes of morbidity and mortality. Congenital heart disease (CHD) is a label for a heterogeneous group of lesions which comprise the commonest group of malformations. Treatment of CHD has only been available for the past half-century, making paediatric cardiology and cardiac surgery relatively new subspecialities. Malta provides an ideal location for historical and epidemiological studies dealing with congenital malformations due to its relatively closed population and lack of antenatal screening programs due to unavailability of termination of pregnancy. Epidemiology Analysis of the epidemiology of CHD in Malta over 1990-94 showed a significant excess of minor ventricular septal defects, which is attributed to high-quality clinical services which diagnose these defects prior to spontaneous closure. A significant excess of lesions causing right ventricular outflow tract obstruction, particularly Pallot's tetralogy, and a relative scarcity of lesions causing left ventricular outflow tract obstruction were also found. A genetic predisposition to right ventricular outflow tract obstruction may be inherent in the Maltese population. A significant seasonal variation in lesions requiring intervention was found with a peak in the third quarter of the year. These deliveries are conceived in the last half of' the year with the first trimester occurring in the peak of the coldest weather. Environmental factors may be influencing predisposed fetuses, precipitating CHD. A significant North-South variation in the overall birth prevalence of CHD was also found, with a higher prevalence in the Southern part of the Island. The demographic trends suggest that environmental factors, rather than genetic factors, may be causing a higher rate of CHD in the South. Historical trends This study has also shown that diagnosis and intervention in all types of CHD has occurred progressively earlier in childhood, with an ever decreasing delay in the application of new techniques to Maltese patients with CHD. These trends were significant and were associated with a significant declining mortality from CHD, both perioperatively and as a crude specific population mortality rate. Conclusion Treatment of CHD has been very successful with a substantial decrease in mortality, increasing the pool of survivors and hence the need for health services. Further work regarding possible environmental conditions which may precipitate CHD could isolate avoidable predisposing factors, allowing a reduction in live births with CHD.