Optimal position and timing of blood pressure and heart rate measurements to detect orthostatic changes in patients with ischemic heart disease

Despite the fact that the clinical assessment of orthostatic changes in blood pressure (BP) and heart rate (HR) are frequently used to evaluate the effects of cardiac drugs, there is no standard procedure for obtaining these measurements. Therefore, the purpose of the present study was to determine the time course of BP and HR changes following the assumption of an upright position before and after administration of a nitrate preparation in ten normal volunteers and ten patients with ischemic heart disease. Two position changes in random sequence were used: supine to sitting and supine to standing. Blood pressure and HR measurements were taken at 0.5, two, three, four, and five minutes after position change and before and after 5 mg of chewable isosorbide dinitrate. Our results showed that initial changes in BP and HR occurred at 0.5 minutes and maximum changes occurred at two minutes after position change and that changes were more marked in the standing position. Therefore, orthostatic changes in BP and HR should be assessed at 0.5 minutes and two minutes after position change. Measurements should be performed first in the sitting position; if no change occurs, measurements should be made in the standing position.