A single ECG lead in the serial monitoring of ischemic injury and necrosis in patients with acute anterior myocardial infarction: Comparison with 49-lead precordial maps and standard ECGs

Abstract

To evaluate the single ECG lead with the maximal ST-segment elevation on admission as a modality suitable for monitoring ischemic injury and necrosis, the author correlated the single lead from 49-lead precordial maps and that from the corresponding standard ECGs with the ECG systems from which they derived. A total of 265 pairs of studies (14 per patient) from 20 patients with acute anterior myocardial infarction were used. Serial recordings were done on admission, at 12 predetermined time intervals during hospitalization, and at discharge. The amplitudes of ST-segment elevation, R waves, and Q waves of the single lead and all of the complexes of the corresponding precordial maps or standard ECGs were measured, using the same methodology. The single ECG lead correlated well with the precordial maps and the standard ECG. Although in serial studies the originally selected single lead was not the one displaying the maximal ST-segment elevation in 29% of the studies, it was always located on a locus immediately adjacent to the new lead in the grid recording the maximal ST. Changes in the precordial map or standard ECG were always detected by the corresponding single lead. The single lead from the standard ECG reflected changes in the precordial map, indicating that a precordial map is not necessary on admission for identification of the single lead. Correlations of R waves and Q waves from the single lead and the precordial map or the single lead and the standard ECG were not as good as the ones found for ST-segment elevation, although they provided monitoring of directional changes of the QRS complexes during hospitalization. Thus, a single lead from a precordial map or standard ECG is adequate for monitoring of the magnitude of ischemic injury in patients with acute anterior myocardial infarction. The single lead also provides some information as to the evolution of changes in the precordial QRS complexes associated with infarction and maintains its traditional role of providing surveillance for arrhythmias or conduction abnormalities.