Introduced into clinical use in 1980, the ICD has become smaller and simpler to implant, while providing better methods to detect and treat sustained ventricular tachyarrhythmias (rapid, irregular heart beat). This study found that ICD use expanded more than 10-fold in clinical practice from 1987 to 1995, with improved mortality rates but high medical expenditures and rates of surgical revision. The investigators identified ICD recipients by use of the hospital discharge databases of Medicare beneficiaries for 1987 through 1995 and of California residents for 1991 through 1995. They linked the initial hospital admission for each ICD patient to previous and subsequent admissions and to mortality files to determine the outcomes of ICD use.

During the study period, over 31,000 ICDs were implanted in Medicare patients, most of whom had been hospitalized for heart attack, congestive heart failure, or ventricular tachycardia at that time or during the previous year. Between 1987 and 1995, the number of hospitals performing the procedure increased from roughly 100 to 500, and the volume of ICD implantations per hospital also rose. Patients who died within 30 days of implantation decreased from 6 to 2 percent, and mortality rates within a year of implantation fell from 19 to 11 percent. Mortality rates at 3 years declined as well, but less sharply, from 38 percent in 1987 to 33 percent in 1992.

Subsequent hospitalizations for ICD complications or surgical replacement were very common and within the first year remained about 5 percent. However, the rate of revision/replacement at 3 years declined from 34 percent from 1987 to 1989 to 18 percent for devices implanted from 1990 to 1992, largely as a result of fewer generator replacements due to improvements in device and battery life. Medicare expenditures for these patients within 30 days of ICD implantation have remained close to $40,000 in 1993 dollars, and 3-year expenditures averaged almost $50,000.