Haemodynamic changes during dobutamine stress echocardiography in patients with and without ischaemia.
We studied haemodynamic changes during dobutamine stress echocardiography 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 stages using infusion rates of 5, 10, 20, 30 and 40 micrograms/kg/min. Heart rate rose from 74 (13) to 123 (21) beats per min with the major increment occurring during the high dose phase of the study (> 20 micrograms/kg/min). Stroke volume was calculated as the product of left ventricular outflow tract cross-sectional area and the velocity integral of the continuous wave aortic signal. Mean stroke volume increased from 67.5 (22) ml pre-test to 82 (22) ml at 20 micrograms/kg/min dose (P < 0.0001) and 85 (21) ml at 40 micrograms/kg/min (P < 0.00001). Only 15 patients (26%) reached their maximal stroke volume by 10 micrograms/kg/min, 38 patients (65%) reached maximal stroke volume by 20 micrograms/kg/min. Patients with ischaemic responses tended to have a blunted rise in stroke volume from 67 (22) ml to 85 (22) ml at maximum compared with a rise from 69 (23) to 92 (19) ml in those without ischaemic (P = 0.09). In conclusion, the early rise in cardiac output during dobutamine stress was mainly due to a rise in stroke volume and the later due to an increase in heart rate. Individual increases in stroke volume did not adequately differentiate between ischaemic and non-ischaemic results.
Mishra
M B
MB
Department of Cardiology, Guy's and St Thomas' NHS Trust, London, UK.
Cooke
R A
RA
Jackson
G
G
Chambers
J B
JB
D000328:Adult; D000368:Aged; D001794:Blood Pressure; D002302:Cardiac Output / Q000187:drug effects*; D002316:Cardiotonic Agents / Q000008:administration & dosage; D003327:Coronary Disease / Q000000981:diagnostic imaging / Q000503:physiopathology; D004280:Dobutamine / Q000008:administration & dosage; D015150:Echocardiography, Doppler; D005260:Female; D006339:Heart Rate / Q000187:drug effects; D006439:Hemodynamics; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013318:Stroke Volume / Q000187:drug effects
D002316:Cardiotonic Agents; D004280:Dobutamine