MONDAY, Sept. 23 (HealthDay News) -- Certain types of heart birth defects increase a child's risk for bacterial heart infections, according to a new study.

Researchers analyzed data from more than 47,000 Canadian children born with heart defects. On average, the risk of bacterial infection of the heart's lining and valves (infective endocarditis) by age 18 was 6.1 cases per 1,000 children within this group.

The risk of infection, however, varied substantially by the type of heart defect. Compared to patients with atrial septal defect -- a heart defect that usually has a low risk for infective endocarditis -- the risk was substantially higher in those with heart defects associated with bluish skin (cyanosis) due to lack of oxygen in the blood, those with endocardial cushion defects and those with left-sided lesions, the study authors said.

An increased risk of infection also was seen in children with congenital heart defects who are under age 3 and children who had heart surgery within the last six months, according to the study, which was published Sept. 23 in the journal Circulation.

"Clinicians treating children with heart defects can help educate parents regarding infective endocarditis and its prevention, particularly in the highest risk groups identified in this study," study co-author Dinela Rushani, of the department of epidemiology, biostatistics and occupational health at McGill University in Montreal, said in a journal news release.

The researchers did not assess the effectiveness of preventive treatments in dealing with these heart infections, but said their findings may help policymakers determine who could benefit from such treatments.

More information

The U.S. National Heart, Lung, and Blood Institute has more about endocarditis.