Objective-To describe the clinical features, prognosis, and treatment of patients presenting with atypical forms of acute myocardial infarction. Design-Consecutive cases of possible acute myocardial infarction were sought from coronary care registers, biochemistry records, and hospital management systems. Case notes were reviewed and predefined epidemiological and clinical variables were abstracted. Setting-20 adjacent hospitals in the former Yorkshire region. Patients-3684 consecutive cases of possible acute myocardial infarction admitted in a three month period were identified, of whom 2096 had a first episode of confirmed acute myocardial infarction. Results-20.2% of all patients admitted with an eventual diagnosis of acute myocardial infarction presented with symptoms other than chest pain. Compared with the group presenting with chest pain, these patients were older (76.6 v 69.1 years, p < 0.001), were more often women (54.6% v 35.3%, p < 0.001), and were more likely to have a history of heart failure (18.6% v 6.9%, p < 0.001). They had a higher 30 and 365 day mortality (49.2% and 61.0%, respectively) compared with patients presenting with chest pain (17.9% and 26.2%). In a Cox regression analysis the hazard ratio for presentation without chest pain was 1.60 (95% confidence interval 1.30 to 1.97) (p < 0.001) adjusted for age, heart rate, blood pressure, left ventricular impairment, and infarction with ST segment elevation as covariates. Importantly, they were also less likely to receive treatments with a proven ability to improve prognosis. Conclusions-Atypical presentation of myocardial infarction without chest pain is common and associated with increased mortality. This may result in part from a failure to use beneficial treatment strategies. (Heart 2001;86:494-498)

Objective-To develop a simple risk model as a basis for evaluating care of patients admitted with acute myocardial infarction. Methods-From coronary care registers, biochemistry records and hospital management systems, 2153 consecutive patients with confirmed acute myocardial infarction were identified. With 30 day all cause mortality as the end point, a multivariable logistic regression model of risk was constructed and validated in independent patient cohorts. The areas under receiver operating characteristic curves were calculated as an assessment of sensitivity and specificity. The model was reapplied to a number of commonly studied subgroups for further assessment of robustness. Results-A three variable model was developed based on age, heart rate, and systolic blood pressure on admission. This produced an individual probability of death by 30 days (P 30 ) where P 30 = 1/(1 + exp(−L 30 )) and L 30 = −5.624 + (0.085 × age) + (0.014 × heart rate) − (0.022 × systolic blood pressure). The areas under the receiver operating characteristic curves for the reference and test cohorts were 0.79 (95% CI 0.76 to 0.82) and 0.76 (95% CI 0.72 to 0.79), respectively. To aid application of the model to routine clinical audit, a normogram relating observed mortality and sample size to the likelihood of a significant deviation from the expected 30 day mortality rate was constructed.Conclusions-This risk model is simple, reproducible, and permits quality of care of acute myocardial infarction patients to be reliably evaluated both within and between centres. (Heart 2001;86:150-154)

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