Copyright © 1991 by the European Society of Cardiology.
© 1991 The European Society of Cardiology
Monitoring of cardiac output during exercise in coronary patients: a Doppler study


*C.N.R. Institute of Clinical Physiology Pisa, Italy
lstituto Patologia Medica of Pisa University Pisa,Italy
Received 12 November 1989; revised 12 July 1990; .
Correspondence: Elena Moacarellt, MD, Istituto Fisologia Clinica, CNR, Via Savi 8, 56100 Pisa, Italy.
Abstract
The monitoring of aortic blood flow velocities by transcutaneous continuous-wave Doppler was performed in 45 patients to determine, non-invasively, the haemodynamic response to exercise in subsets of coronary patients during a multistage supine exercise tests. Group I consisted of 14 patients with ischaemia on effort (IE); group II, 12 patients with both IE and prior myocardial infarction (MI); group III, 19 patients with MI and no IE; there were also 12 normals. Peak flow velocity (PV) indices of cardiac output (CO), of peripheral resistance (PR) and of stroke work (SW) were measured every min. Resting CO was lower and PR higher in coronary patients than in normals. With exercise, for the same muscular work, CO increased less in IE patients (group I: y = 26.9 +1.8 x cm sec1; Group II: y = 21.9 +1.8 x cm sec1) than in MI (group III: y = 26.6 + 2.1 x cms1) and in normals (y = 35 + 2.7x cms1) and PR decreased less. This suggested a more efficient distribution of CO towards working muscles. A shallower increase in SW was observed in all coronary patients in comparison with normals even if resting SW was significantly lower only in patients with MI (groups II and III). PV increased up to peak exercise only in group III, while it tended to plateau in ischaemic patients even earlier than IE occurred on the ECG. Thus, Doppler monitoring of aortic flow velocities contributed to the understanding of mechanisms underlying the haemodynamic response to exercise in different groups of coronary patients, information which permits a more rational therapeutic approach.
Key Words: Doppler echocardiography exercise testing left ventricular function coronary artery disease