Cardiol Young 2004; 14: 396–401 © Cambridge University Press ISSN 1047-9511 C ARDIAC ANOMALIES ARE AMONGST THE MOST common congenital malformations, and are said to afflict about 1% of all live-born chil- dren. 1–12 The cause of the lesions is unknown, but genetic and environmental factors, such as maternal diseases or the use of medications and drug abuse during pregnancy, are thought to play a role. 13 The defects are often a component of a number of syn- dromes, such as Marfan’s, as well as some chromoso- mal anomalies such as Down’s syndrome. 13 To obtain better understanding of the etiology of the lesions, it is important to know their precise incidence, as well as their distribution in the population. These factors are likely to become increasingly significant with the ongoing increase in genetic knowledge. The pur- pose of our study, therefore, was to document the incidence and type of congenital cardiac malforma- tions occurring in Iceland between 1990 and 1999. A similar study had been performed in our country Original Article Congenital cardiac malformations in Iceland from 1990 through 1999 Sigurdur Sverrir Stephensen, Gunnlaugur Sigfusson, Herbert Eiriksson, Jon Thor Sverrisson, Bjarni Torfason, Asgeir Haraldsson, Hrodmar Helgason Children’s Hospital, University Hospital of Iceland, Hringbraut, Reykjavik, Iceland Abstract Introduction and Background: About 1% of live-born children have congenital malformations of the heart. The aim of our study was to investigate the incidence of such defects in children born in Iceland during a period of 10 years, extending from 1990 through 1999. Materials and Methods: Information about the patients was obtained from medical records from two hospitals that cover the whole country, a private clinic of pediatric cardiologists, an echocardiography database, autopsy reports, and death certificates. We investigated the distribution of specific malformations, the age at diagnosis, the symptoms leading to the diagnosis, the source of referral, and treatment and quality of life. Results: Between 1990 and 1999, there were 44,013 live births in Iceland, of which 740 patients were diagnosed with congenital cardiac malformations, accounting for 1.7% of the live-born children. The distribution was made up of 338 patients with ventricular septal defect (45.7%), 90 with atrial septal defect (12.2%), 85 with patency of the arterial duct (11.5%), 48 with pulmonary valvar stenosis (6.5%), 38 with a bicuspid aortic valve (5.1%), 28 with aortic coarctation (3.8%), 22 with tetralogy of Fallot (3.0%), 14 with transposed great arteries (1.9%), 11 with aortic stenosis (1.5%), 10 with atrioventricular septal defect and common atrioventricular orifice (1.4%), 9 with mitral valvar regurgitation (1.2%), 7 with sub-aortic stenosis (0.9%), and 5 with hypoplasia of the left heart (0.7%). Extracardiac anom- alies were seen in 89 patients (12.0%). Chromosomal defects were seen in 36 patients, of whom 28 had Down’s syndrome. Discussion: The annual incidence of diagnosis of patients with congenital cardiac malformations increased during the period of study. This was noted for minor defects, but the incidence of the major anom- alies did not alter. Our observed yearly incidence, at 1.7%, was higher than noted in a previous study covering the years 1985 through 1989, and is also higher than in other population-based studies. The most likely expla- nation is the fact that access to pediatric cardiologists in Iceland is very good. Diagnosis, registration, and follow-up are conducted by only a few cardiologists, and take place at a single center for pediatric cardiology. Keywords: Congenital heart defects; incidence; epidemiology Correspondence to: Gunnlaugur Sigfusson MD, University Hospital of Iceland, Barnaspitali Hringsins, Hringbraut, Reykjavik 101, Iceland. Tel: +354 543 1000; Fax: +354 543 3021; E-mail: gulli@landspitali.is Accepted for publication 23 February 2004