Implantable cardioverter-defibrillator therapy after acute myocardial infarction: the results are not shocking.

The risk of sudden death is highest early after myocardial infarction (MI) and progressively declines over the ensuing 6 to 12 months. Nevertheless, several randomized clinical trials have failed to show a survival benefit for implantable cardioverter-defibrillators when implanted early after MI in high-risk patients. The etiology of this acute MI-sudden cardiac death paradox is unclear, but may be related to the changing nature of the substrate over the several month period after acute MI. Further investigation is needed to delineate the actual causes of death in the early post-MI period and which interventions can be implemented to reduce the increased rate of sudden death that is observed.