Incidence and prognostic impact of new-onset atrial fibrillation in patients with septic shock: a prospective observational study

Abstract

Introduction: Since data regarding new-onset atrial fibrillation (AF) in septic shock patients are scarce, the purpose of the present study was to evaluate the incidence and prognostic impact of new-onset AF in this patient group.

Methods: We prospectively studied all patients with new-onset AF and all patients suffering from septic shock in a non-cardiac surgical intensive care unit (ICU) during a 13 month period.

Results: During the study period, 687 patients were admitted to the ICU, of which 58 patients were excluded from further analysis due to pre-existing chronic or intermittent AF. In 49 out of the remaining 629 patients (7.8%) new-onset AF occurred and 50 out of the 629 patients suffered from septic shock. 23 out of the 50 patients with septic shock (46%) developed new-onset AF. There was a steady, significant increase in C-reactive protein (CRP) levels before onset of AF in septic shock patients. ICU mortality in septic shock patients with new-onset AF was 10/23 (44%) compared with 6/27 (22%) in septic shock patients with maintained sinus rhythm (SR) (P = 0.14). During a 2-year follow-up there was a trend towards an increased mortality in septic shock patients with new-onset AF, but the difference did not reach statistical significance (P = 0.075). The median length of ICU stay among surviving patients was longer in patients with new-onset AF compared to those with maintained SR (30 versus 17 days, P = 0.017). The success rate to restore SR was 86%. Failure to restore SR was associated with increased ICU mortality (71.4% versus 21.4%, P = 0.015).

Conclusions: AF is a common complication in septic shock patients and is associated with an increased length of ICU stay among surviving patients. The increase in CRP levels before onset of AF may support the hypothesis that systemic inflammation is an important trigger for AF.

Figure 1

Time course of CRP plasma concentrations before, during and after onset of new AF. (a) Patients with new-onset atrial fibrillation (AF) and septic shock. (b) Patients with new-onset AF without septic shock. The median, interquartile range (box), minimum and maximum are shown. Day 0, day of occurrence of AF; Day -3, three days before new-onset of AF; Day 5, five days after occurrence; P₁-value, analysis of variance (ANOVA) over time; P₂-value, comparison of C-reactive protein (CRP) levels Day 1 versus CRP levels Day -3 (Dunnett's method). (b) Note: P₂-value was not calculated for patients with new-onset AF without septic shock as ANOVA did not demonstrate significant change over time.

Figure 2

ICU mortality. AF, atrial fibrillation; SR, sinus rhythm.

Figure 3

Kaplan-Meier survival curves for septic shock patients with new-onset atrial fibrillation and septic shock patients with maintained sinus rhythm. AF, atrial fibrillation; SR, sinus rhythm.

Figure 4

ICU length of stay of surviving patients. The median, minimum, maximum and interquartile range (box) are shown. AF, atrial fibrillation; SR, sinus rhythm.