Arrhythmias during remodeling after myocardial infarction

Abstract

The effect of mechanical on electrical remodeling or electrical instability of the heart shows that it is essential for the prevention of sudden death to avoid or delay mechanical remodeling and neurohumoral activation after myocardial infarction. In other words, patients after myocardial infarction prone to neurohumoral activation need to be treated with ACE inhibitors or perhaps AT1-receptor blockers and beta blockers to maintain electrical stability. MADIT I and MUSTT study showed that patients with severe ventricular dysfunction after myocardial infarction are at high risk of sudden death, especially in presence of electrical instabilities indicated by ventricular arrhythmias. These patients certainly need an automatic implantable cardioverter defibrillator (ICD). It is not clear so far whether or not the indication needs to be extended according to the MADIT II study. In other words, need all postmyocardial infarction patients with reduced pump function an ICD? There is no doubt that many patients with an ejection fraction below 30% have ventricular arrhythmias and fulfil therefore the inclusion criteria for the MADIT I or MUSTT study. In MADIT I, a run of three ventricular premature beats force was sufficient to fulfil the inclusion criteria. Another important consequence of the temporal correlation between mechanical and electrical remodeling is that specific attention must be directed to these interrelations in patients after myocardial infarction. Patients who die of sudden death show in comparison to surviving patients a substantial dilatation of the left ventricular during 6 months of observation which parallel the increasing incidence of ventricular premature beats. The consequence for therapy would be that in patients who present with left ventricular dilatation during 6 months after myocardial infarction, electrical instability is present and a high risk of sudden death exists. These patients probably will benefit from an ICD.