Abstract Body (Do not enter title and authors here): Background: Cardiogenic shock (CS) and cardiac arrest (CA) are serious complications in ST-elevation myocardial infarction (STEMI) patients, with lack of long-term data according to their timing of occurrence.

Objective: This study sought to determine the incidence and the relationship between timing of occurrence and prognostic impact of CS and CA following STEMI in the long-term follow-up.

Methods: We conducted a retrospective analysis of consecutive STEMI patients treated from 2004 to 2017. Patients were divided into four groups based on the occurrence of neither CA nor CS, CA only, CS only, and both CA and CS (CA-CS-, CA+, CS+ and CA+CS+, respectively). Adjusted Cox regression analysis was used to assess the independent association between the CS and CA categories and mortality. The timing of their occurrence was evaluated according to initial cardiac catheterization as pre-, during- or post-procedure.

Results: A total of 1,603 STEMI patients were followed for a median of 3.6 years. CA and CS occurred in the 12.2% and 15.9% of patients, and both impacted long-term mortality [adjusted HR 2.59 (95%CI 1.53-4.41), p<0.001, and HR 3.16 (95%CI 2.21-4.53, p<0.001], respectively as shown in Figure 1. CA+CS+ occurred in 7.3%, with the strongest association with higher long-term mortality [adjusted HR 5.36 (95%CI 3.80-7.55), p<0.001]. Using flexible parametric models with B-splines and landmark analysis, the increased mortality was restricted to the first ~10 months after STEMI. In addition, among CS patients, overall mortality rates were higher at all CS timings, pre-, during and post-procedure (all with p<0.001). In contrast, CA during initial cardiac catheterization was not associated with overall mortality (p<0.183), while both CA pre- and post-procedure (all with p<0.001) were associated with higher mortality.

Conclusion: CS and CA complicating patients presenting with STEMI were associated with higher long-term mortality rate, especially in the first 10 months. While CS at any time frame appeared to impact clinical outcomes, only CA pre- and post- cardiac catheterization were associated with higher mortality rates.