Ischaemia monitoring with on‐line vectorcardiography during dobutamine stress echocardiography in patients after an episode of unstable coronary artery disease

Abstract

Abstract. Lundin P, Eriksson SV, Andrén B, Lindahl B, Tor nvall P, Melcher A (Danderyd Hospital, Danderyd, University Hospital, Uppsala, Karolinska Hospital, Stockholm, Sweden). Ischaemia monitoring with on-line vectorcardiography during dobutamine stress echocardiography in patients after an episode of unstable coronary artery disease. J Intern Med 1998; 244: 61-70.Objectives. This study investigated the ability of online vectorcardiography (VCG) to detect myocardial ischaemia as assessed by dobutamine stress echocardiography after an episode of unstable coronary artery disease. Design. Dobutamine stress test (incrementally infused doses of 5, 10, 20, 30 and 40 g kg Ϫ1 per minute) was performed during simultaneous VCG monitoring. QRS vector difference (QRS-VD), ST vector magnitude (ST-VM), ST change vector magnitude (STC-VM) and T change vector magnitude (TC-VM) were monitored. A new wall motion abnormality or worsening of abnormal wall motion was regarded as indicating a positive dobutamine stress test. Subjects. Fifty-five patients with unstable angina pectoris and 16 patients with an acute non-Q-wave myocardial infarction were studied 5-8 days after admission. Results. A positive dobutamine stress test was observed in 37 patients (52%). The sensitivity, specificity and total accuracy of identifying patients with a positive dobutamine stress test by VCG were: 38%, 91% and 63% for QRS-VD; 59%, 88% and 73% for ST-VM; 84%, 79% and 82% for STC-VM; and 86%, 23% and 56% for TC-VM. Patients with a positive dobutamine stress test showed higher maximum VCG values than patients with a negative dobutamine stress test (QRS-VD, P Ͻ 0.01; ST-VM, P Ͻ 0.001; STC-VM, P Ͻ 0.001). The maximum VCG values were related to the number of segments showing new or worsening wall motion abnormality (QRS-VD: r ϭ 0.41, P Ͻ 0.001; ST-VM: r ϭ O.44, P Ͻ 0.001; STC-VM: r ϭ 0.57, P Ͻ 0.001). Conclusion. STC-VM and ST-VM seem to be the best VCG variables for detection of myocardial ischaemia as assessed by dobutamine stress echocardiography.

Deterioration in peak systolic velocity is closely related to ischaemia during angioplasty: a vectorcardiographic and tissue Doppler imaging study

“…Steg et al [18] showed that ST changes induced by transient coronary occlusion in humans were related to scintigraphic quantitative indexes of myocardial ischaemia, but the correlation was mostly with the severity of ischaemia rather than with the size of the area at risk. Lundin and co-workers [19] found STC-VM to be related to ischaemia, as assessed by dobutamine stress echocardiography. Patients with a positive dobutamine stress test showed higher maximum STC-VM values than patients with a negative dobutamine stress test.…”

Vectorcardiography: A Tool for Non-invasive Detection of Reperfusion and Reocclusion?

“…In multivariate analysis, reduction of ST-segment elevation was the only independent predictor of functional recovery (30). One study indicated that on-line VCG may predict ischemia in the predischarge exercise test (31) as well as ischemia in dobutamine stress echocardiography (32). This finding is interesting since recent trials have indicated that not all patients with acute MI should follow an invasive strategy including routine angiography followed by revascularization if feasible (33,34).…”