QT Prolongation in Postinfarction Patients and Sudden Death: Which Relationship?

Abstract

The prognosis of postmyocardial infarction (post-MI) patients depends in particular upon the interaction between ischemia, left ventricular dysfunction, and electrical instability. The risk can be found in the center of an imaginary triangle formed by these three factors. These factors interact bidirectionally (Fig. 1), so that any of the apices affects the next directly or indirectly, and the modification of any one of these factors consequently alters the other two. Ischemia, therefore, affects left ventricular dysfunction either directly or indirectly through the electrical instability pathway and the sames happens with other two factors. We should also emphasize that the three angles of the triangle, electrical instability, left ventricular dysfunction, and ischemia, include different parameters as we can see in Fig 2. In Tables 1–3 we summarize the most important relationships between these three parameters.