© 2004 Diabetes UK. Diabetic Medicine, 21, 1025–1031 1025 Introduction In acute coronary syndromes, the heightened risk attributable to diabetes is not a function of the severity of injury, nor of the severity of global left ventricular systolic dysfunction, both of which are quantitatively similar in patients with and without Correspondence to: Professor Adam D. Timmis, London Chest Hospital, Bonner Road, London E2 9JX, UK. E-mail: timmis@lch.demon.co.uk Abstract Aims To compare major determinants of myocardial oxygen demand (heart rate, blood pressure and rate pressure product) in patients with and without diabetes admitted with acute coronary syndromes. Methods A cross-sectional study of the relation between diabetes and haemo- dynamic indices of myocardial oxygen demand in 2542 patients with acute coronary syndromes, of whom 1041 (41.0%) had acute myocardial infarction and 1501 (59.0%) unstable angina. Results Of the 2542 patients, 701 (27.6%) had diabetes. Major haemodynamic determinants of myocardial oxygen demand were higher in patients with than without diabetes: heart rate 80.0 ± 20.4 vs. 75.2 ± 19.2 beats/minute (P < 0.0001); systolic blood pressure 147.3 ± 30.3 vs. 143.2 ± 28.5 mmHg ( P = 0.002); rate-pressure product 11533 ± 4198 vs. 10541 ± 3689 beats/minute × mmHg (P < 0.0001). Multiple regression analysis confirmed diabetes as a significant determinant of presenting heart rate [multiplicative coefficient (MC) 1.05; 95% confidence interval (CI) 1.03–1.07; P < 0.0001], rate pressure product (MC 1.09; CI 1.05–1.12; P < 0.0001) and systolic blood pressure, which was estimated to be 3.9 mmHg higher than in patients without diabetes (P = 0.003). These effects of diabetes were independent of a range of baseline variables including acute left ventricular failure and mode of presentation (unstable angina or myocardial infarction). Conclusions In acute coronary syndromes, heart rarte and other determinants of myocardial oxygen demand are higher in patients with than without diabetes, providing a potential contributory mechanism of exaggerated regional ischaemia in this high-risk group. Diabet. Med. 21, 1025–1031 (2004) Keywords acute coronary syndromes, blood pressure, diabetes, heart rate, myocardial oxygen demand Abbreviations ACE, angiotensin converting enzyme; CI, confidence interval; CK, creatine kinase; LVF, left ventricular failure; MC, multiplicative coefficient; RPP, rate-pressure product; UA, unstable angina. Blackwell Publishing, Ltd. Oxford, UK DME Diabetic Medicine 0742-3071 Blackwell Publishing, 2004 21 Original Article Original article Diabetes and determinants of oxygen demand in acute coronary syndromes K. Foo et al. The effect of diabetes on heart rate and other determinants of myocardial oxygen demand in acute coronary syndromes K. Foo, N. Sekhri, C. Knight*, A. Deaner*, J. Cooper†, K. Ranjadayalan, A. Suliman and A. D. Timmis‡ Department of Cardiology Newham HealthCare NHS Trust, London, *Department of Cardiology, Barking Havering and Redbridge NHS Trust, Essex, †MRC Cardiovascular Group, London and ‡Department of Cardiology, London Chest Hospital, Barts London NHS Trust, London, UK Accepted 7 April 2004