Fewer cases of structural abnormalities of the heart have been reported lately in the United States. Researchers note that deaths from congenital heart defects have fallen by 24 per cent from 1999 to 2006.

Such abnormalities include various health disorders such as irregular heartbeats, congestive heart failure and high blood pressure in arteries.

As part of her study, Suzanne Gilboa, an epidemiologist at the National Center on Birth Defects and Developmental Disabilities, pinpointed a congenital heart defect as an underlying cause of 27,960 deaths, a rate of 1.2 deaths per 100,000 people, back in 2006. About 48 per cent of them were kids.

She found that blacks had the highest mortality rate, and there was a decline of 15 per cent in death rate for all ethnic groups. Whites had a decline of 25 per cent. She also noted that males had higher death rates; most of them had a left heart syndrome, an underdeveloped left side of the heart.

However her team of researchers was not sure of the reason for a drop in such deaths, but improved diagnostic practices, technology and treatment could be the contributing factors.