Effectiveness of Exercise After an ICD

Inclusion Criteria: * ICD implantation for primary or secondary prevention of sudden cardiac arrest, -ability to read, speak and write English,- * access to a reliable phone for 6 months after study entry, * able to ambulate without assist devices for at least 5-10 minutes/day * greater than 18 years of age. Exclusion Criteria: * current diagnosis of serious mental disorder, * regular non-medical use of illicit drugs (opiates, cocaine, amphetamines, etc.), -unstable angina, myocardial infarction, ICD shock or heart surgery within previous 3 months * pregnancy * concurrent participation in an exercise program \> 5 days/week.