Pathophysiology of myocardial currents of injury: contributions of new electrocardiographic methods

Mario J. Mc Loughlin, Investigaciones Médicas Florida, Buenos Aires, Argentina
Santiago Obregón-Rosas, Dirección de Enseñanza, Hospital Ángeles Pedregal, Ciudad de México, México; Facultad Mexicana de Medicina, Universidad La Salle, Ciudad de México, México

Diastolic and systolic currents of injury are fundamental for understanding electrocardiographic alterations in acute myocardial ischemia. These currents result from electrical gradients between ischemic and healthy zones, driven by differences in depolarization and repolarization. The diastolic current, directed toward healthy tissue, and the systolic current, oriented toward the injured region, explain phenomena such as TQ depression (diastolic current of injury) and QRS complex modifications accompanied by ST-segment deviations (systolic current of injury). Historical and contemporary studies have elucidated the underlying pathophysiology of these currents, emphasizing changes in radial myocardial activation, alterations in electrical vectors, and the potential presence of intramural conduction blocks. Furthermore, precise correlations between these electrocardiographic findings and acute ischemic events have been demonstrated in both experimental and clinical models. Understanding these currents not only facilitates the diagnosis of myocardial ischemia but also enhances the capacity for prompt intervention. This knowledge underscores the central role of the electrocardiogram in clinical practice and cardiovascular research.

Keywords: Electrocardiogram. Injury currents. Myocardial ischemia. ST-segment elevation myocardial infarction.