London, Sep 17 (IANS): The memory of a heart attack gets stored in genes through epigenetic changes -- chemical modifications of DNA that turns our genes on or off, a study has found.

Cardiovascular diseases (CVDs) which are the leading causes of death worldwide are influenced by both heredity and environmental factors.

CVD includes all the diseases of the heart and circulation including coronary heart disease, angina, heart attack, congenital heart disease and stroke.

The study examined epigenetic changes -- that can lead to the development of various diseases -- in people who have had a previous heart attack.

"During a heart attack the body signals by activating certain genes. This mechanism protects the tissue during the acute phase of the disease, and restores the body after the heart attack. It is therefore likely that epigenetic changes are also associated a heart attack", said Asa Johansson, researcher at the Uppsala University in Sweden.

The results of the study showed that there are many epigenetic changes in individuals who had experienced a heart attack.

Several of these changes are in genes that are linked to cardiovascular disease.

However, it was not possible to determine whether these differences had contributed to the development of the disease, or if they live on as a memory of gene activation associated with the heart attack, the researchers said.

"We hope that our new results should contribute to increasing the knowledge of the importance of epigenetic in the clinical picture of a heart attack, which in the long run could lead to better drugs and treatments", Johansson added.

For the study, the team took blood samples from the northern Sweden population health study. Individuals with a history of a CVD were identified in the cohort. It included individuals with hypertension, myocardial infarction, stroke, thrombosis and cardiac arrhythmia.

The results were published in the journal Human Molecular Genetics.