People who were born with a heart defect have a much higher risk of suffering a stroke, a new study has found.

A congenital heart defect is an abnormality that is present at birth. While some defects can be life-threatening as soon as a baby is born, others may go undetected or fail to produce any symptoms until later in life

Researchers in Canada assessed the medical records of almost 30,000 people with congenital heart defects. All were aged between 18 and 64.

They found that ischaemic stroke rates among those with congenital defects were up to 12 times higher before the age of 55 compared with the general population. This is the most common type of stroke and is caused by a sudden blockage in the blood vessels (arteries) supplying the brain, by a blood clot.

Ischaemic stroke rates were also up to four times higher among those aged between 55 and 64.

Meanwhile, haemorrhagic stroke rates were up to six times higher in adults with congenital defects aged under 55 and up to three times higher in those aged 55-64.

A haemorrhagic stroke is caused by a bleed on the brain.

"We knew there was a connection between heart failure and stroke in patients with heart defects, but we were surprised to discover it was the strongest predictor. Our study also suggests that other well-known risk factors for stroke, such as irregular heartbeat and high blood pressure, may be under-detected in patients born with a heart defect," the researchers from McGill University noted.

They said that as adults with heart defects have an increased risk of suffering a stroke, they should be monitored regularly by a cardiologist.

"Patients, their families and friends should also learn the FAST signs to recognise stroke and understand how to get professional medical help quickly if they believe they are having a stroke," they added.

FAST stands for:

-Face - has the person's face fallen on one side?

-Arms - can the person raise both arms and keep them there?

-Speech - is their speech slurred?

-Time - if you seen any of these signs, it is time to call 999.

Details of these findings are published in the journal, Circulation.