Congenital heart defects (CHDs) are problems with the heart¿s structure that are present at birth. CHDs are the most common birth defect and occur in almost 1% of births. Over 85% of babies born with CHD now live to become adults. Our group has previously shown that there were 96,000 adults with congenital heart disease in Canada in 2000 and that this population is growing rapidly. With this proposal we are examining the quality and safety of the care received by this growing group of patients. Guidelines have been published in Canada and the US indicating that adults with heart defects should be followed in specialized centers. But in Canada, at the moment less than 30% of the adult patients are meeting these recommendations. We want to know why adult patients with heart defects are not receiving high quality care in the specialized centres that is recommended. These patients often require life-long care with numerous procedures to diagnose and treat their condition. Commonly, they are subject to x-ray procedures that emit ionization radiation. Atomic bomb survivors in Japan have an increased risk of cancer from high doses of radiation. We want to know if our patients are also at risk for cancer as a potential danger to radiation that uses ionization radiation. For health care workers, the government mandates badges for those who work in hospitals to monitor the radiation they are exposed to. Perhaps the same should exist for patients. With this study, we are proposing to provide information to inform our patients and our governments.