1. Dynamic QRS-complex and ST-segment monitoring by continuous vectorcardiography during carotid endarterectomy† 
S. Kawahito, H. Kitahata, K. Tanaka, J. Nozaki, S. Oshita 
British Journal of Anaesthesia 
Volume 90, Issue 2, Pages (February 2003)
DOI: /bja/aeg031
Copyright © 2003 British Journal of Anaesthesia Terms and Conditions

2. Fig 1
(a) Placement of the eight surface electrodes for vectorcardiography recording as described by Frank. Five electrodes (A, C, E, I, M) are located at the same transverse level (approximately the fifth interspace), H is on the back of the neck, and F is the standard left leg electrode. The eighth electrode is for the ground and usually placed on the right leg or hip. The signals from these electrodes are converted via an acquisition module into three orthogonal components projected in the three perpendicular axes x, y, and z, and then sent to a microcomputer system. (b) The reference complex is the average of the first 2 min of data recorded for each patient. The QRS vector difference is the shaded area between the two average complexes. The ST vector magnitude is the deviation of the ST-segment from the baseline, measured 60 ms after termination of the QRS complex.
British Journal of Anaesthesia  , DOI: ( /bja/aeg031)
Copyright © 2003 British Journal of Anaesthesia Terms and Conditions

3. Fig 2
Trend curves of QRS vector difference and ST vector magnitude during carotid endarterectomy for patient 4. With continuous dynamic monitoring of vectorcardiography, sudden changes in QRS vector difference and ST vector magnitude status after induction of anaesthesia can be seen.
British Journal of Anaesthesia  , DOI: ( /bja/aeg031)
Copyright © 2003 British Journal of Anaesthesia Terms and Conditions

4. Fig 3
Trend curves of QRS vector difference and ST vector magnitude during carotid endarterectomy for patient 9. This patient's trend curves display gradual changes in QRS vector difference and ST vector magnitude after cross-clamping of the carotid artery.
British Journal of Anaesthesia  , DOI: ( /bja/aeg031)
Copyright © 2003 British Journal of Anaesthesia Terms and Conditions