The concept of cancellation of electromotive forces has been employed in explaining the vagaries of electrocardiographic (ECG) appearances in patients with multiple myocardial infarctions. This interpretive approach attributes the modification of QRS complexes resulting from infarctions to areas of myocardial necrosis opposite to each other. The underlying vectorial ECG analysis can be extended to the interpretation of false negative ECG results in the setting of exercise stress testing. The authors present a case of a patient who developed exercise-induced myocardial ischemia involving two planes of his heart, opposite each other. Thallium-201 myocardial scintigraphy showed evidence of severe reversible myocardial ischemia, while the ECG did not reveal such changes. The authors expounded on the importance of ischemic ST-segment counterpoise in explaining some of these false ECG responses to exercise stress testing.

Keywords:
Exercise stress test, Thallium perfusion imaging, Exercise electrocardiography, False negative stress ECG, Myocardial ischemia, Coronary artery disease
This content is only available via PDF.
1994
Copyright / Drug Dosage / Disclaimer
Copyright: All rights reserved. No part of this publication may be translated into other languages, reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying, recording, microcopying, or by any information storage and retrieval system, without permission in writing from the publisher.
Drug Dosage: The authors and the publisher have exerted every effort to ensure that drug selection and dosage set forth in this text are in accord with current recommendations and practice at the time of publication. However, in view of ongoing research, changes in government regulations, and the constant flow of information relating to drug therapy and drug reactions, the reader is urged to check the package insert for each drug for any changes in indications and dosage and for added warnings and precautions. This is particularly important when the recommended agent is a new and/or infrequently employed drug.
Disclaimer: The statements, opinions and data contained in this publication are solely those of the individual authors and contributors and not of the publishers and the editor(s). The appearance of advertisements or/and product references in the publication is not a warranty, endorsement, or approval of the products or services advertised or of their effectiveness, quality or safety. The publisher and the editor(s) disclaim responsibility for any injury to persons or property resulting from any ideas, methods, instructions or products referred to in the content or advertisements.
You do not currently have access to this content.