HEMODYNAMIC-CHANGES DURING DOBUTAMINE STRESS ECHOCARDIOGRAPHY IN PATIENTS WITH AND WITHOUT ISCHEMIA

We studied haemodynamic changes during dobutamine stress echocardiogra phy in 69 patients (mean age 58 years, 6 female, 63 male) referred for investigation of chest pain. We used a standard protocol of 3 min sta ges using infusion rates of 5, 10, 20, 30 and 40 mu g/kg/min. Heart ra te rose from 74 (13) to 123 (21) beats per min with the major incremen t occurring during the high dose phase of the study (>20 mu g/kg/min). Stroke volume was calculated as the product of left ventricular outfl ow tract cross-sectional area and the velocity integral of the continu ous wave aortic signal. Mean stroke vol;me increased from 67.5 (22) ml pre-test to 82 (22) ml at 20 mu g/kg/min dose (P<0.0001) and 85 (21) ml at 40 mu g/kg/min (P<0.00001). Only 15 patients (26%) reached their maximal stroke volume by 10 mu g/kg/min, 38 patients (65%) reached ma ximal stroke volume by 20 mu g/kg/min. Patients with ischaemic respons es tended to have a blunted rise in stroke volume from 67 (22) ml to 8 5 (22) ml at maximum compared with a rise from 69 (23) to 92 (19) ml i n those without ischaemia (P=0.09). In conclusion, the early rise in c ardiac output during dobutamine stress was mainly due to a rise in str oke volume and the later rise due to an increase in heart rate. Indivi dual increases in stroke volume did not adequately differentiate betwe en ischaemic and non-ischaemic results. Copyright (C) 1997 Elsevier Sc ience Ireland Ltd.