AIMS To investigate personality traits and sympatho-vagal modulation of heart rate variability (HRV) during acute myocardial infarction (AMI), assessing their relationships and their long-term prognostic value. METHODS AND RESULTS Psychological traits and 24 h HRV were prospectively investigated in 246 patients at discharge of an AMI. Patients were followed-up to 8 years for the occurrence of cardiac death and non-fatal reinfarction. Low coping and anxiety traits associated with reduced HRV characterized the study population. At univariate analysis, low emotional sensitivity and insecurity, relative tachycardia, reduced high frequency (HF), and low frequency power and pNN50 were predictive of cardiac death at 8-year follow-up. At multivariable analysis, low emotional sensitivity and low HF power remained predictive, with a relative risk of 4.18 (P=0.003) and 2.76 (P=0.007), respectively; also the type of infarction (Q vs. non-Q) and hospital length of stay were independent predictive variables. CONCLUSION Anxiety and emotional sensitivity were significant predictors of 8-year cardiac mortality after AMI. Reduced HF power, a recognized marker of vagal withdrawal, increased the risk.