Objective: Numerous studies have shown that a substantial number of patients suffer from adverse events (AEs) as a result of hospital care. However, specific data on AEs in acute cardiac care are scarce. The current manuscript describes the development and validation of a specific instrument to evaluate patient safety of a predefined care track for patients with acute myocardial infarction (AMI). Design: Retrospective patient record review study. Setting and participants: A total of 879 hospital admissions treated in a tertiary care centre for an AMI (age 64±12 years, 71% male). Main outcome measure: In the first phase, the medical records of patients with AMI warranting coronary angiography or coronary intervention were analysed for process deviations. In the second phase, the medical records of these patients were checked for any harm that had occurred which was caused by the healthcare provider or the healthcare organisation (AE) and whether the harm that occurred was preventable. Results: Of all 879 patients included in the analysis, 40% (n=354) had 1 or more process deviation. Of these 354 patients, 116 (33%) had an AE. Patients with AE experienced more process deviations compared with patients without AE (2±1.7 vs 1.5±0.9 process deviations per patient, p=0.005). Inter-rater reliability in assessing a causal relation of healthcare with the origin of an AE showed a κ of 0.67 (95% CI 0.51 to 0.83). Conclusions: This study shows that it is possible to develop a reliable method, which can objectively assess process deviations and the occurrence of AEs in a specified population. This method could be a starting point for developing an electronic tracking system for continuous monitoring in strictly predefined care tracks.