The use of implantable cardiac devices in the management of heart failure has increased, but patient selection and inhospital outcomes in clinical practice have not been critically explored. Therefore, we evaluated the inhospital mortality and costs associated with patients with heart failure who received an implantable cardioverter defibrillator, cardiac resynchronization device, or device lead. We analyzed admissions with International Classification of Diseases, Ninth Revision, procedure codes for implantation/revision of cardioverter defibrillator or cardiac resynchronization device and a primary or secondary diagnosis code for heart failure in a prospective hospital database from 2004 to 2005. Odds ratios were calculated to quantify risk for mortality. Average accumulated costs over time were calculated before and after day of first device implant procedure. Among 27,907 hospitalizations, inhospital mortality varied based on day of device implantation and use of intravenous inotropic therapy. Mortality was 0.3% for patients who did not require inotropic drugs versus 3.3%, 6.6%, and 15.2% for patients who required initiation of drug before, on the day of, or after device implantation, respectively. Logistic regression demonstrated that the most potent risk for inhospital mortality was the use of inotropic drugs. Similar trends were observed for any vasoactive therapy. There was a marked increase in costs associated with these admissions. Implantation of cardiac devices during a hospitalization for heart failure may be associated with significant inhospital mortality if patients require intravenous vasoactive therapy. Risk stratification methodology that incorporates ongoing/anticipated need for these drugs will likely improve clinical decision making.