Background: The first multicenter automatic defibrillator implantation trial (MADIT-I) was a landmark study that identified a significant reduction in mortality among high-risk patients with ischemic cardiomyopathy treated prophylactically with an implantable cardioverter defibrillator (ICD), yet the direct and indirect impact of this trial on clinical practice is unknown.
Methods: We performed a retrospective analysis of the 679 patients who underwent primary ICD implantation between 1994 and 2000 at a single academic center. The baseline characteristics of each patient were determined at the time of ICD implantation, and the vital status of all patients was determined as of January 1, 2004.
Results: The number of patients who received an ICD based on the MADIT-I criteria increased from 1.4% in 1994 to 6.1% in 2000. An additional 60 patients were identified that met many but not all of the trial criteria and consisted of patients with a history of a recent revascularization or myocardial infarction, syncope, or an ejection fraction >or=35%. The number of patients who received ICDs in this expanded MADIT-I subset also grew from 5.6% in 1994 to 14.6% in 2000. Mortality during a mean follow-up of 4.7 years was significantly higher in the MADIT-I group than in the expanded MADIT-I, or the remaining primary prevention and secondary prevention subsets.
Conclusion: The MADIT-I has not only led to an increase in the number of patients undergoing prophylactic ICD implantation, but in clinical practice it has also been extrapolated to a broader population that has a different degree of risk than originally studied.