The effect of diabetes on heart rate and other determinants of myocardial oxygen demand in acute coronary syndromes.
OBJECTIVE
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 haemodynamic 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 x 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 rate 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.
Department of Cardiology Newham HealthCare NHS Trust, London, UK.
K
K
Foo
N
N
Sekhri
C
C
Knight
A
A
Deaner
J
J
Cooper
K
K
Ranjadayalan
A
A
Suliman
A D
AD
Timmis
D000208:Acute Disease; D001794:Blood Pressure / Q000502:physiology; D003327:Coronary Disease / Q000150:complications / Q000378:metabolism*; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000378:metabolism*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D012737:Sex Factors
D010100:Oxygen