Precordial ST Depression Research Articles

Surface electrocardiogram in the detection of transmural myocardial ischemia during coronary artery occlusion

To examine whether coronary occlusion causing transmural ischemia was accurately reflected by ST-segment elevation on routine electrocardiograms, intracoronary and surface electrocardiograms were simultaneously recorded during percutaneous transluminal coronary angioplasty (PTCA). The study group consisted of 54 patients who had intracoronary ST-segment elevation during transient coronary occlusion (left anterior descending [LAD]: 25 patients, left circumflex [LC]: 19 patients, right coronary artery: 12 patients). Elevation of the ST segment on the surface electrocardiogram (≥0.1 mV) was recorded in 84% of patients during LAD dilatation, in 32% of patients during LC dilatation (p < 0.01 vs LAD and right), and in 92% of patients during right coronary dilatation (not significant vs LAD). The magnitude of intracoronary ST elevation was 1.10 ± 0.8, 1.68 ± 1.2 and 0.8 ± 0.6 mV for the LAD, LC and right occlusions, respectively (not significant). Thus, despite the comparable magnitude of intracoronary ST elevation, LC occlusion resulted in ST-segment elevation on the surface electrocardiogram in significantly fewer patients than did LAD or right occlusion. During LC occlusion, 9 patients had no electrocardiographic changes and 4 had only precordial ST depression. Thus, in patients with transmural ischemia during right or LAD occlusions, concordant ST elevation on the surface electrocardiogram is common. In contrast, ST-segment elevation is an insensitive marker of LC occlusion. In patients with ongoing ischemic symptoms and isolated precordial ST depression or no repolarization abnormalities, LC occlusion should be considered in the differential diagnosis.

Reciprocal ST segment changes in acute inferior myocardial infarction: clinical, haemodynamic and angiographic implications

Reciprocal ST segment changes are frequent during acute inferior myocardial infarction, yet their significance remains controversial. In order to investigate the implications of these changes, the ECG obtained on admission for 83 patients with acute inferior myocardial infarction was compared with the clinical course and the results of angiographic and coronary arteriographic studies performed an average of 3 weeks after the onset of symptoms. Group 1 consisted of 59 patients with at least 1 mm of horizontal on downsloping ST segment depression in at least 1 of leads V1 to V4. Groups 2 consisted of 24 patients without precordial ST depression in this area. Group 1 patients were generally older than group 2 patients (59.6 +/- 6.4 versus 54 +/- 5.3 yr, P less than 0.01) had higher total creatine kinase (CK) levels and MB fractions (1835 +/- 940 versus 875 +/- 305, P less than 0.01, 269 +/- 102 versus 95 +/- 35 for MB fraction) and more complications during the hospital course (80% versus 38% P less than 0.01) and greater left ventricular dysfunction (ejection fraction 52.2 +/- 6% for group 1 versus 59.2 +/- 7% for group 2; cardiac index 2.75 +/- 0.41 min-1 m-2 for group 1 versus 3.25 +/- 0.31 min-1 m-2 for group 2 P less than 0.005). No difference was observed on biplane angiography as far as left ventricular wall kinesis was concerned.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic significance of precordial ST-segment depression during inferior acute myocardial infarction

To study the mechanism and prognostic importance of precordial ST-segment depression during inferior acute myocardial infarction, 162 patients admitted during 1969 through 1982 were identified. Patients with ST depression in leads V 1, V 2 and V 3 had significantly larger infarctions as assessed by a QRS scoring system. Hospital mortality was 4% (3 of 75) among patients without ST depression, and 13% (11 of 87) in patients with ST depression. The relation between the amount of ST depression and hospital mortality was significant (p < 0.001 by logistic regression), and remained significant (p < 0.003) after adjusting for other potentially prognostic factors. Among patients discharged from the hospital, the 5-year survival was 92% in those without precordial ST depression and 80% in those with precordial ST depression (p = 0.058 by the Cox model). Precordial ST-segment depression on the admission electrocardiogram during an inferior acute myocardial infarction indicates a larger infarction, predicts a higher hospital mortality and suggests a worse long-term prognosis after discharge.

Inferoseptal myocardial infarction: Another cause of precordial ST-segment depression in transmural inferior wall myocardial infarction?

Electrocardiographic ST-segment depression in the anterior precordial leads is a frequent observation during the initial hospital phase of acute transmural inferior myocardial infarction (MI), but is of uncertain significance. No available clinical studies have examined the prevalence of inferoseptal necrosis complicating inferior MI. Therefore, the clinical course, electrocardiographic features, radionuclide angiograms and cardiac enzyme changes in 57 patients with transmural inferior MI who did not have prior anterior or concomitant "true posterior" MI, associated anterior or posterolateral asynergy by radionuclide ventriculography, or left or right bundle branch block were reviewed retrospectively. Patients were categorized according to the presence (group A) or absence (group B) of precordial ST-segment depression and according to the presence (group I) or absence (group II) of radionuclide septal wall motion abnormalities. There were no significant differences in global left ventricular ejection fraction (group A, 49 +/- 8, group B, 52 +/- 41; group I, 51 +/- 7, group II, 51 +/- 6), right ventricular ejection fraction (group A, 45 +/- 9, group B, 42 +/- 7; group I, 43 +/- 8, group II, 41 +/- 8), or clinical outcome in the hospital. However, chi-square analysis revealed a significant (p less than 0.05) association between the presence or absence of septal asynergy and the presence or absence of precordial ST depression. In addition, average peak creatine kinase elevation (group I, 761 +/- 164 IU; group II, 698 +/- 178 IU) attained marginal significance by paired t test (p = 0.06). Precordial ST-segment depression during transmural inferior MI is frequently associated with septal asynergy by gated radionuclide angiography (15 of 26 patients, 58%).(ABSTRACT TRUNCATED AT 250 WORDS)

Implications of “reciprocal” ST segment depression associated with acute myocardial infarction identified by positron tomography

This study was performed to determine whether patients with myocardial infarction with apparently reciprocal ST segment depression exhibit abnormal metabolism in zones distant from the primary zone of infarction. Positron emission tomography was performed after the intravenous injection of carbon-11 palmitate in 20 patients with acute myocardial infarction. Infarction was anterior in 7 patients and inferior in 13. Patients with anterior infarction did not show ST segment depression in the inferior leads and all of the patients exhibited normal homogeneous accumulation of palmitate in the inferior and posterior walls. Nine patients with inferior infarction (69%) exhibited ST segment depression (apparently reciprocal or due to anterior wall ischemia) in the anterior precordial leads. Myocardial injury tended to be greater in the primary zone of necrosis among patients with inferior infarction and "reciprocal" ST segment depression compared with those without anterior ST segment depression. This was reflected by the greater total inferior ST segment elevation (0.48 ± 0.35 versus 0.07 ± 0.19 mV [± standard deviation], p < 0.05), peak plasma MB creatine kinase activity (354 ± 134 versus 80 ± 34 IU/liter, p < 0.05) and tomographically estimated infarct size (58 ± 13 versus 33 ± 10 PET-g-eq). Three of the nine patients with inferior infarction and precordial ST depression exhibited anterior tomographic defects underlying the ST segment depression. Thus, although most of the patients with inferior infarction and precordial lead ST segment depression had no anterior wall metabolic compromise (67%) indicating that the anterior ST segment changes were truly reciprocal phenomena, in some the precordial electrocardiographic abnormalities reflected impaired metabolism in the anterior wall indicative of ischemia.