Aim. The present study aims to determine the relationship between family performance indices (cohesion, expressiveness, and conflict) and the risk of myocardial infraction.

Background. Cardiovascular diseases, especially myocardial infraction, is the first factor of fatality in the world and also in Iran. The etiology of myocardial infraction is a very complicated. One of the risk factors overlooked in the studies associated with the etiology of cardiovascular disorders is family and performance indices of the family.

Method. The present research was conducted by a case-control cross-sectional design. The data were collected from two groups, a group of 50 patients with myocardial infraction symptoms (case group) referring to Heshmat Specialized Hospital for Cardiology in Rasht and Tehran Specialized Heart Center, and a group of 50 healthy persons (control group) with no symptoms of myocardial infraction. The data gathering tool included Family Relationships Index. The data were analyzed by SPSS version 16 using MANOVA method.

Findings. There was a statistically significant difference between case and control groups in terms of control variables: history of myocardial infarction, education, history of smoking, history of cholesterol and hypertension (p<0.01), and history of diabetes (p<0.05). There was also a statistically significant difference between groups in terms of cohesion, and conflict indices (p<0.01).

Conclusion. Deficiency in family performance indices, including cohesion, and conflict in family relationships, are among the main risk factors of myocardial infarction. Therefore, it is necessary to prepare and implement social, behavioral and educational interventions in order to prevent negative effects of inadequacies in family performance indices.