LATERAL AND ANTERIOR RECIPROCAL ELECTROCARDIOGRAPHIC CHANGES - RELATIONSHIP TO ST SEGMENT ELEVATION AND UNDERLYING CORONARY-ARTERY DISEASE IN INFERIOR MYOCARDIAL-INFARCTION

The electrocardiogram in patients with acute inferior myocardial infar ction frequently displays ST depression in non-infarct leads, The sign ificance of this finding is uncertain. The relationship between ST dep ression, ST elevation and arteriographic severity of coronary artery d isease was explored, 22 patients with acute inferior myocardial infarc tion, receiving thrombolysis and undergoing acute (within seven hours of the onset of chest pain) coronary angiography were studied prospect ively. The electrocardiographic ST segment elevation in the inferior l eads and ST segment depression in the lateral and in the anterior prec ordial Leads were measured, In each group of Leads, the maximum value of ST deviation in any lead as well as the sum of the values for ST de viation in the individual leads was determined, Gensini scores of tota l coronary artery disease and component scores for the major coronary arteries were determined from the coronary arteriogram, There was a st rong correlation of maximum inferior ST elevation with both maximum la teral ST depression (r = 0.96, p < 0.001) and with maximum anterior pr ecordial ST depression (r = 0.78, p < 0.001). The corresponding correl ations for sum of ST deviations were r = 0.91, p < 0.001 and r = 0.79, p < 0.001 respectively, There was no relationship between Gensini sco res of coronary artery disease and measures of electrocardiographic ST segment depression or elevation, Electrocardiographic ST depression i n non-infarct leads in patients with inferior myocardial infarction, d oes not provide information regarding the degree of coronary artery di sease. The ST depression in both lateral and anterior precordial leads correlates with and is a reflection of inferior ST elevation.