CONCLUSION
Substantial fluctuations of EF occur among patients with ischemic or non-ischemic cardiomyopathy who are eligible for ICD implantation. These data suggest that EF improvement in these patients represents remission rather than true recovery of the cardiomyopathy and may help explain the continued risk of SCD after improvement in EF. These data support the need for indefinite medical and continued device therapy after improvement in EF.