ABC | Volume 113, Nº5, November 2019

Original Article Congo et al. New-Onset atrial fibrillation in STEMI Arq Bras Cardiol. 2019; 113(5):948-957 Figure 1 – Flowchart with patients included and excluded. Patients with STEMI diagnosis (n = 6957) Patients enrolled (n = 6325) Group 1 – Patients who did not develop AF during in-hospital stay for STEMI (n = 5960) Group 2 – Patients with new onset AF during in-hospital stay for STEMI (n = 365) Patients excluded due to previous diagnosis of AF, previous anticoagulation therapy or missing information (n = 632) It was also associated to a more frequent need of Swan‑Ganz catheter, intra-aortic balloon pump, invasive mechanical ventilation and transvenous cardiac pacing (Table 7). The duration of hospital stay was higher in patients of group 2 [3 (3; 5) days vs. 5 (4; 9) days, p < 0.001]. In-hospital mortality was higher in patients who developed new onset AF (3.8% vs. 13.4%; p < 0.001) (Figure 3). Although new-onset AF was associated with higher incidence of complications and in-hospital mortality, by multivariate analysis, new-onset AF was not found as an independent predictor of in-hospital mortality [OR 1.19 (0.62–2.27), p = 0.608]. We identified age, prior stroke, inferior located STEMI and complete AV block as independent predictors of new-onset AF (Table 8). Discussion These population-based data reflect the comprehensive experience of a community in a “real-life” setting and is more representative of those treated in clinical practice than populations enrolled in randomized controlled trials. In our population, new-onset AF was found in 5.8% of patients hospitalized for STEMI, which is in line with recent published data. 1,7 However, this number is lower than most older studies, suggesting that despite an increasingly older population with higher prevalence of comorbidities, the incidence of AF in the setting of acute MI has declined. 8,9 New-onset AF was found more frequently in older patients, female sex, with higher prevalence of comorbidities, including hypertension, diabetes, previous stroke and previous heart failure and, therefore, higher CHA 2 DS 2 -VASc scores. According to Schmitt et al., 1 the use of interventional coronary revascularization has been associated with a notable decline in the AF incidence. 1 However, one of the major findings of this study is that new-onset AF complicating STEMI is independent of reperfusion strategy. Reperfusion was successfully accomplished in both groups with no difference regarding the type of reperfusion and no difference in the number of affected or treated vessels between both groups. This is consistent with the OACIS study, which states that AF complicating the clinical course of MI appears to be irrespective of treatment by thrombolytics or PCI. 10,11 However, there seems to be a favorable effect of early reperfusion therapy on preventing new-onset AF, as it also was suggested by a previous study. 8 The use of thrombectomy devices, which may suggest a cardioembolic cause, were more frequently used in patients who developed AF, raising the question that some patients with new-onset AF may have had undiagnosed paroxysmal AF. 12 950