Scottish researchers say by screening the relatives of middle-aged heart attack sufferers many lives would be saved.
Past research has indicated in many illnesses hereditary factors play a significant role and this is particularly true of heart disease.
One in every five heart attacks happen to middle-aged patients and the researchers suggest that if direct relatives were screened for their risk for heart disease 42% of premature heart attacks could be prevented.
It is already well known that the siblings and children of younger heart attack victims (under 55 years in men and 65 years in women) have a high risk of heart disease, and though there are set guidelines such people are not as a rule routinely assessed.
The researchers from the University of Glasgow believe that if key signs for risks such as high blood pressure and cholesterol in family members were identified and treated many premature heart attacks would be prevented.
Children and partners are often also at increased risk from lifestyle factors, such as smoking and a diet too high in saturated fats.
The researchers estimated that the 15,600 patients admitted for heart attack in 2004 in England and Wales had 32,000 siblings and they then calculated that 218 of those would have a heart attack within a year and 1,148 would have a heart attack within five years; of that number the researchers say four out of every ten were preventable.
Experts assess an individuals' risk on the basis of hereditary and lifestyle factors such as diet and smoking as well as weight, blood pressure and cholesterol.
They recommend that anyone with a 20% 10-year risk of having a heart attack or stroke should receive preventive treatment, such as cholesterol-lowering drugs called statins.