Open AccessThe role of “Ischemic ST‐segment Counterpoise” in rendering the response of exercise electrocardiogram falsely negative
Author(s) -
Madias John E.,
Khan Mujtaba,
Manyam Bose
Publication year - 1997
Publication title -
clinical cardiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.263
H-Index - 72
eISSN - 1932-8737
pISSN - 0160-9289
DOI - 10.1002/clc.4960200517
Subject(s) - medicine , cardiology , coronary artery disease , electrocardiography , ischemia , thallium , perfusion , st segment , artery , heart rate , myocardial infarction , blood pressure , inorganic chemistry , chemistry
Exercise electrocardiogram (ECG) has a high rate of false negative results in comparison with simultaneously performed thallium‐201 perfusion scintigraphy, particularly in patients with single‐vessel coronary artery disease, low exercise workload, inadequate heart rate rise, and resting ECG abnormalities. We present the case of a patient in whom thallium‐201 SPECT scintigram revealed equally extensive and severe myocardial ischemia in two myocardial planes opposite each other. The accompanying exercise ECG did not disclose ischemic changes despite the adequacy of heart rate rise in this patient with severe right and left anterior descending coronary artery disease. We propose, as an explanation for this phenomenon, that in this patient the ischemic ST‐segment vectors of equal magnitude and direction but of opposite sense, generated during stress, cancelled each other (“ischemic ST‐segment counterpoise”), thus rendering the exercise ECG normal.