Low diastolic blood pressure was one of the independent predictors of ischemia-like findings of electrocardiogram in patients who underwent coronary angiography.

BACKGROUND: The underlying cause of a high cardiovascular event rate in the population with low diastolic blood pressure (DBP) has not been fully elucidated.

METHODS AND RESULTS: The relationship between DBP and ischemia-like findings on electrocardiography (ECG) was investigated in 187 patients who underwent coronary angiography. Patients with conditions affecting ECG (e.g. patients taking digitalis or those with old myocardial infarction, complete right bundle branch block, or hypokalemia) were excluded from the analyses. Ischemia-like ECG was defined as having one or more of the following: borderline Q wave [Minnesota code (MC) I 3], ST depression (MC IV 1-3), negative T wave (MC V 1-3), and complete left bundle branch block (MC VII 1). Based on this definition, 70 of 187 patients (37%) had ischemia-like ECG. Compared with the group without it, the group with ischemia-like ECG included more females (p<0.01), and had lower values of body mass index (p = 0.01), DBP (p<0.01), estimated glomerular filtration rate (p<0.01), left ventricular ejection fraction (LVEF; p<0.01), and higher values of age (p<0.01) and left ventricular mass index (LVMI; p<0.01). The severity of coronary artery disease did not differ between the groups. Receiver operating characteristics curve analysis revealed that 74.5 mmHg was the optimal cut-off point of DBP to predict ischemia-like ECG (area under curve, 0.63; 95% confidence interval, 0.55-0.71, p = 0.003). There were no significant relationships between systolic blood pressure and ischemia-like ECG. A multivariate analysis showed that female sex, low DBP (≤ 74.5 mmHg), LVMI, and LVEF were the significant factors for the ischemia-like ECG. The odds ratio of low DBP was 2.53 (95% confidence interval, 1.19-5.40; p = 0.02).

CONCLUSIONS: Low DBP was one of the significant predictors of the ischemia-like ECG in the present study. Myocardial ischemia may be a part of the cause of high cardiovascular morbidity in the population with low DBP.