ST-segment level and slope in exercise-induced myocardial ischemia evaluated with body surface potential mapping.

Body surface potential mapping (BSPM) is superior to 12-lead electrocardiography for detection of acute and old myocardial infarctions (MIs). We used BSPM to examine electrocardiographic criteria for acute reversible myocardial ischemia. BSPM with 123 channels was performed in 45 patients with coronary artery disease (CAD) and 25 healthy controls during supine bicycle exercise testing. Of the 45 patients, 18 patients had anterior, 14 had posterior, and 13 had inferior ischemia documented by coronary angiography and thallium scintigraphy. The ST amplitude was measured 60 ms after the J-point and the ST slope calculated by fitting a regression line from the J-point to 60 ms after it. The optimal locations for detecting ST depression and ST-slope decrease were identified. In the pooled CAD patient group, the optimal location for ST depression was 5 cm below standard lead V(5) (CAD group: -70 +/- 70 microV; controls: 70 +/- 80 microV, p <0.001). Using a cut-off value of -10 microV, the ST depression separated the patients with CAD from controls with a sensitivity of 84% and a specificity of 96%. The ST slope became more horizontal in the patient group than in the control group. The optimal location for ST-slope decrease was over the left side (CAD group: 20 +/- 20 microV/s; controls: 720 +/- 320 microV/s, p <0.001). Using a cut-off value of 320 microV/s, the ST slope separated patients with CAD from controls with a sensitivity of 93% at a specificity level of 88%. The area under the receiver operating characteristic curve of ST slope tended to be higher than the one of ST depression (97% vs 93%; p = 0.097). In conclusion, regions sensitive for ST depression and for ST-slope decrease could be identified in BSPM, despite variation in the location of ischemia and the presence or absence of a history of MI. ST slope is a sensitive and specific marker of transient myocardial ischemia, and might perform even better than ST depression.

[1]  B. Horáček,et al.  Body surface potential maps with low-level exercise in isolated left anterior descending coronary artery disease. , 1988, The American journal of cardiology.

[2]  S Yasui,et al.  Body surface distributions of ST segment changes after exercise in effort angina pectoris without myocardial infarction. , 1985, American heart journal.

[3]  E. Braunwald.  Heart Disease: A Textbook of Cardiovascular Medicine , 1992, Annals of Internal Medicine.

[4]  K. Ikeda,et al.  Detection of diseased coronary artery by exercise ST-T maps in patients with effort angina pectoris, single-vessel disease, and normal ST-T wave on electrocardiogram at rest. , 1989, Circulation.

[5]  C W Haws,et al.  Detection and localization of coronary artery disease with body surface mapping in patients with normal electrocardiograms. , 1987, Circulation.

[6]  T. Ohtake,et al.  ST-T isointegral analysis of exercise stress body surface mapping for identifying ischemic areas in patients with angina pectoris. , 1988, American heart journal.

[7]  P. Toutouzas,et al.  Improved detection of coronary artery disease by exercise electrocardiography with the use of right precordial leads. , 1999, The New England journal of medicine.

[8]  L De Ambroggi,et al.  Diagnostic value of body surface potential mapping in old anterior non-Q myocardial infarction. , 1988, Journal of electrocardiology.

[9]  Jukka Nenonen,et al.  Recording locations in multichannel magnetocardiography and body surface potential mapping sensitive for regional exercise-induced myocardial ischemia , 2001, Basic Research in Cardiology.

[10]  V. Froelicher,et al.  Comparison of computer ST criteria for diagnosis of severe coronary artery disease. , 1993, The American journal of cardiology.

[11]  H P Selker,et al.  Coronary care unit triage decision aids: how do we know when they work? , 1989, The American journal of medicine.

[12]  I. Menown,et al.  Early diagnosis of right ventricular or posterior infarction associated with inferior wall left ventricular acute myocardial infarction. , 2000, The American journal of cardiology.

[13]  I. Menown,et al.  ST depression only on the initial 12-lead ECG: early diagnosis of acute myocardial infarction. , 2001, European heart journal.

[14]  R A Nadeau,et al.  New body surface isopotential map evaluation method to detect minor potential losses in non-Q-wave myocardial infarction. , 2000, Circulation.

[15]  P M Rautaharju,et al.  Identification of First Acute Q Wave and Non‐Q Wave Myocardial Infarction by Multivariate Analysis of Body Surface Potential Maps , 1991, Circulation.

[16]  P M Rautaharju,et al.  Body Surface Potential Mapping of ST Segment Changes in Acute Myocardial Infarction Implications for ECG Enrollment Criteria for Thrombolytic Therapy , 1993, Circulation.