Effectiveness of amiodarone versus digitalis for heart rate control in critically ill patients with new-onset atrial fibrillation

Figures

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  Figure 1. Study flow chart. ICU, intensive care unit; ECMO, extracorporeal membrane oxygenation; LVAD, left-ventricular assist device. Study flowchart showing the number of patients and respective exclusion criteria. Patients receiving both amiodarone and digitalis were excluded from primary endpoint analysis for methodical reasons. Patients in need of a cardioversion after medication were also excluded, because we intended to examine solely the effectiveness of amiodarone or digitalis medication for heart rate control. Patients with an ICU stay of less than 6 h after onset of atrial fibrillation were excluded, because we deemed this time interval as an insufficient follow-up for the study.

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  Figure 2. Heart rate decreases over time. Bpm, beats per minute; h, hour. Boxplots (whiskers: 5th and 95th percentile) show representative heart rates for patients treated with amiodarone (red) or digitalis (blue) during the study interval. The horizontal line marks 110 bpm, the vertical line represents medication start. Heart rates both in patients treated with either amiodarone or digitalis decreased over time (Friedman test: p < 0.001 for both groups). Median heart rates both in amiodarone and digitalis treated patients remained consistently lower than at study start (Bonferroni-Holm corrected p < 0.01 for each time point versus 0 h). Patients receiving amiodarone presented with a higher heart rate at 0 h (133 bpm [IQR: 109 bpm to 147 bpm] versus 116 bpm [IQR: 100 bpm to 133 bpm]; p < 0.001).

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  Figure 3. Heart rate delta over time. Bpm, beats per minute; h, hour. Boxplots (whiskers: 5th and 95th percentile) show representative heart rates for patients treated with amiodarone (red) or digitalis (blue) during the study interval. * indicates Mann–Whitney U p-values < 0.05 (Bonferroni-Holm corrected for comparison of 6 subgroups). Numbers within the boxes represent the included patients for this time point. Patients receiving amiodarone presented with a greater relative decrease in heart rate at any measured time point within the study interval.

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  Figure 4. Association of heart rate control with inflammation. Bpm, beats per minute; CRP, C-reactive protein; h, hour. Patients are grouped by amiodarone (red) versus digitalis (blue) and CRP tertile (1st: < 143 mg/L; 2nd: 143 to 263 mg/L; 3rd: > 263 mg/L). Comparison of the tertile lines shows that increasing CRP values were associated with greater heart rate decrease in association with amiodarone treatment than with digitalis treatment (univariate ANOVA: p < 0.001 both for the factors CRP tertile and medication group).