Objectives: We aimed to quantify the frequency and nature of early complications after implantable cardioverter-defibrillator(ICD) implantation in general practice, and estimate the incremental costs of those complications to the health care system. Background: Cardioverter-defibrillator implantation rates are rising quickly. Little has been published regarding the outcomes and costs of these procedures in unselected populations. Methods: Using Medicare Provider Analysis and Review(MedPAR) files, we identified 30,984 admissions containing procedure codes for new ICD or cardiac resynchronization therapy defibrillator implantation in fiscal year 2003. The frequencies of eight complicating diagnoses during these admissions were determined. Length of stay(LOS) and total hospital costs, derived using whole-hospital cost to charge ratios, were calculated for each admission. The incremental effects of any and each complication on LOS and hospital cost were estimated in multivariable models, adjusting for demographic factors and comorbid conditions. Results: The mean cost for all admissions was ＄42,184(median ＄37,902) with mean LOS of 4.7 days(median 2.0 days). One or more complications were coded in 10.8%of admissions, most commonly “mechanical complication of the ICD”and hemorrhage/hematoma. The occurrence of any complication increased adjusted LOS by 3.4 days and costs by ＄7,251. Each of the individual complications was associated with highly significant increases in both LOS(1 to 10 days) and hospital cost(＄5,000 to ＄20,000). Conclusions: In fiscal 2003, 10.8%of Medicare patients undergoing cardioverter-defibrillator implantation experienced one or more early complications, associated with significant increases in LOS and costs. Efforts to reduce these complications could have significant clinical and financial benefits. Objectives: We aimed to quantify the frequency and nature of early complications after implantable cardioverter-defibrillator (ICD) implantation in general practice, and estimate the incremental costs of those complications to the health care system. Background: Cardioverter-defibrillator implantation rates are rising quickly Little has been published regarding the outcomes and costs of these procedures in unselected populations. Methods: Using Medicare Provider Analysis and Review (MedPAR) files, we identified 30,984 admissions containing procedure codes for new ICD or cardiac resynchronization therapy defibrillator implantation in fiscal year 2003 The frequency of eight complicating diagnoses during these admissions were determined. Length of stay (LOS) and total hospital costs, derived using whole-hospital cost to charge ratios, were calculated for each admission. The incremental effects of any and each complication on LOS and hospital cost were estimated in multivariable models, a Results: The mean cost for all admissions was $ 42,184 (median $ 37,902) with mean LOS of 4.7 days (median 2.0 days). One or more complications were coded in 10.8% of admissions, most commonly “The mechanical complication of the ICD” and hemorrhage / hematoma. The occurrence of any complication increased adjusted LOS by 3.4 days and costs by $ 7,251. Each of the individual complications was associated with highly significant increases in both LOS (1 to 10 days) and Hospital costs ($ 5,000 to $ 20,000). Conclusions: In fiscal 2003, 10.8% of Medicare patients undergoing cardioverter-defibrillator implantation experienced one or more early complications, associated with significant increases in LOS and costs. Efforts to reduce these complications could have significant clinical and financial benefits.