Influence of time between last myocardial infarction and prophylactic implantable defibrillator implant on device detections and therapies. "Routine Practice" data from the SEARCH MI registry

Abstract

Background: A multicenter European Registry, SEARCH-MI, was instituted in the year 2002 in order to assess patients' outcomes and ICD interventions in patients with a previous MI and depressed LV function, treated with an ICD according to MADIT II results. In this analysis, we evaluate the influence of the time elapsed between last myocardial infarction (MI) and prophylactic cardioverter defibrillator (ICD) implant on device activations.

Methods: 643 patients with left ventricular dysfunction (mean LVEF 26 ± 5%) and NYHA class I-III were prospectively followed for 1.8 ± 1.2 years in a multicenter registry. The population was divided into 3 groups according to the time between last MI and ICD implant: [1] from 40 days to less than 1.5 years; [2] from 1.5 to less than 7 years and [3] at least 7 years.

Results: The cumulative incidence of ventricular tachyarrhymias and appropriate device therapy (ATP or shock) were higher in patients implanted longer time from last MI (Gray's Test p=0.002 and p=0.013 respectively). No significant differences were seen in all cause mortality (Gray's Test p=0.618) or sudden cardiac death across the MI stratification groups (Gray's Test p=0.663).

Conclusions: Patients implanted with an ICD longer after the MI have a higher chance of presenting ventricular tachyarrhythmias and appropriate ICD therapy, while no differences were seen in overall mortality. These observations may be important for improving patient targeting in sudden death prevention.

Figure 1

Cumulative incidence estimates of ventricular tachyarrhythmias (panel A) and appropriate device therapy (ATP or shock) (panel B) in patients with a prior MI ≥7years (dotted red line), MI ≥ 1.5 years and <7 years (dashed black line) and MI >40 days and <1.5 years (blue line).

Figure 2

Cumulative incidence estimates of all cause mortality (panel A) and sudden cardiac death (panel B) in patients with a prior MI ≥7years (dotted red line), MI ≥ 1.5 years and <7 years (dashed black line) and MI >40 days and <1.5 years (blue line).