Study of the Implantable Cardioverter Defibrillator (ICD) Intracardiac Electrograms

Inclusion Criteria:

history of acute MI at least 4 weeks old
non-ischemic LV dysfunction for at least 9 months
who have an EF < or = to 35%
who was resuscitated from sudden cardiac arrest (ventricular tachyarrhythmia)
undergone implantation of an FDA-approved ICD for primary or secondary prevention of SCD

Exclusion Criteria:

inability or unwillingness to provide valid informed consent
pregnancy
any condition other than cardiac disease that was associated with a high likelihood of death during 1 year after enrollment