Optimal timing of implantable cardioverter-defibrillator implantation after myocardial infarction: a decision analysis.

BACKGROUND

The optimal timing of implantable cardioverter defibrillator (ICD) placement for the primary prevention of sudden cardiac death after myocardial infarction (MI) remains unknown.

METHODS AND RESULTS

We developed a Markov model to investigate the optimal timing of ICD implantation after MI (no ICD, ICD at 60 days, 6 months, and 1 year) in patients who meet current guidelines. Estimates of arrhythmic death (baseline risk 6%, range 1-20% per year), nonarrhythmic death, and ICD efficacy were based upon MADIT-II and other contemporary post-MI clinical trials. We used both deterministic and stochastic modeling processes in our analysis. After 10 years follow-up, the baseline probability of survival was higher in those treated with ICD implantation versus not (42% vs 30%, P < 0.001). Survival was highest with ICD implantation at 60 days versus 6 months versus 1 year: 42.4%, 42.3%, and 42.0% (P = 0.0028). ICD implantation at 60 days provided a mean incremental survival of 0.28 months and 0.84 months per patient (compared with implantation at 6 months and 1 year). In sensitivity analyses, patients' competing risk for nonarrhythmic death was the primary determinant of benefit from ICD implantation. Overall, ICD implantation at 60 days resulted in the greatest life expectancy over a wide range of plausible nonarrhythmic and arrhythmic death rates.

CONCLUSIONS

The benefits of early ICD implantation are modest when compared with delayed implantation at 6 months/1 year. Our results suggest that making sure a patient receives an ICD, when appropriate, may be more important than the timing of the implantation procedure.