Unrecognized myocardial infarction: five-year incidence, mortality, and risk factors

Area of Science:

• Cardiology
• Epidemiology
• Preventive Medicine

Background:

• Heart attacks (myocardial infarctions) can be clinically apparent or silent (unrecognized).
• Understanding the incidence and risk factors for unrecognized infarcts is crucial for cardiovascular health.
• Previous research has primarily focused on clinical manifestations of heart disease.

Purpose of the Study:

• To determine the incidence of unrecognized infarcts in a healthy adult population.
• To identify significant risk factors associated with unrecognized infarcts.
• To compare the long-term mortality outcomes of unrecognized infarcts versus clinical infarcts and no infarcts.

Main Methods:

• Prospective study over 5 years involving 9509 healthy adult subjects.
• Multivariate analysis to identify risk factors for unrecognized infarcts.
• 7-year mortality follow-up of study participants.

Main Results:

• Annual incidence of unrecognized infarcts was 3.6 per 1000 persons; clinical infarcts were 5.3 per 1000 persons.
• Key risk factors for unrecognized infarcts included age, left axis deviation, left ventricular hypertrophy, smoking, blood pressure, and peripheral vascular disease.
• Cholesterol, diabetes, anxiety, and psychosocial factors were not significant for unrecognized infarcts, unlike clinical infarcts.
• Computer-ECG interpretation discrepancies predicted higher rates of unrecognized infarcts.
• Unrecognized infarcts were associated with higher mortality than no infarcts but lower mortality than clinical infarcts.

Conclusions:

• Unrecognized infarcts represent a significant cardiovascular event with distinct risk factor profiles compared to clinical infarcts.
• Age, specific ECG findings, hypertension, smoking, and PVD are key predictors of silent myocardial infarctions.
• Individuals with unrecognized infarcts face an elevated mortality risk, underscoring the need for early detection and management strategies.