TORONTO - Heart disease caused by a buildup of plaque in the arteries appears to be on the rise among Quebecers aged 40 and younger, says a Montreal researcher, who found the condition accounts for a significant proportion of sudden deaths in that age group.

Dr. Dabit Arzamendi, a fellow at the Montreal Heart Institute, told the Canadian Cardiovascular Congress in Toronto on Monday that 46.5 per cent of sudden deaths in Quebecers aged 40 and under were caused by heart disease.

Arzamendi, who is from Spain, said he was struck by the number of relatively young people who were coming into the Montreal hospital needing a stent to prop open their plaque-ridden arteries.

"My experience with patients in Barcelona is quite different from here," he said in a release. "I've never seen such young people coming into the lab needing an intervention."

Arzamendi studied autopsy reports of patients who had unexpected, sudden deaths. Of 90 people who had died of cardiac causes, more than half had diseased and narrowed arteries, a condition known as atherosclerosis that can lead to heart attack or stroke.

The rest died from congenital heart defects or conduction system abnormalities and arrhythmias (abnormal heart rhythms).

"Heart defects and arrhythmias were the main cause of death in the cardiac victims 20 years or younger, but narrowing of the arteries was the main cardiac killer of people in the 20-to 40-year age group," he said.

"This is a wake-up call for Quebecers and all Canadians," commented Toronto cardiologist Dr. Beth Abramson, a spokeswoman for the Heart and Stroke Foundation. "Since many of the risk factors for atherosclerosis are controllable, most of these deaths could likely have been prevented."

Atherosclerosis is the narrowing of artery walls caused by the buildup of fatty deposits, known as plaque, in the blood. High blood pressure, elevated blood levels of cholesterol and triglycerides, obesity, diabetes and smoking can all contribute to the development of plaque.