Study of the Implantable Cardioverter Defibrillator (ICD) Intracardiac Electrograms

Prospective Observational Study of the ICD Intracardiac Electrograms for Prediction of Ventricular Tachyarrhythmias and Congestive Heart Failure

The purpose of this study is to determine whether waveforms of the intracardiac electrograms, acquired through an ICD, can be used:

• to predict malignant ventricular arrhythmias, requiring appropriate ICD therapies, and
• to predict progression of heart failure in patients with ICD.

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