ABC | Volume 113, Nº5, November 2019

Original Article New-Onset Atrial Fibrillation in St-Segment Elevation Myocardial Infarction: Predictors and Impact on Therapy And Mortality Kisa Hyde Congo, 1 A driana Belo, 2 João Carvalho, 1 David Neves, 1 Rui Guerreiro, 1 João António Pais, 1 Diogo Brás, 1 Mafalda Carrington, 1 Bruno Piçarra, 1 Ana Rita Santos, 1 José Aguiar 1 Hospital Espírito Santo de Évora, 1 Évora – Portugal Centro Nacional Coleção de Dados em Cardiologia, 2 Coimbra – Portugal Mailing Address: Kisa Hyde Congo • Hospital Espírito Santo de Évora - Largo Senhor da Pobreza, s/n Évora 7000‑811 – Portugal E-mail: kisacongo@gmail.com, kisahydecongo@gmail.com Manuscript received October 05, 2018, revised manuscript January 04, 2019, accepted February 13, 2019 DOI: 10.5935/abc.20190190 Abstract Backgrund: New-onset atrial fibrillation complicating acute myocardial infarction represents an important challenge, with prognostic significance. Objective: To study the incidence, impact on therapy and mortality, and to identify predictors of development of new‑onset atrial fibrillation during hospital stay for ST-segment elevation myocardial infarction. Methods: We studied all patients with ST-elevation myocardial infarction included consecutively, between 2010 and 2017, in a Portuguese national registry and compared two groups: 1 – no atrial fibrillation and 2 – new-onset atrial fibrillation. We adjusted a logistic regression model data analysis to assess the impact of new-onset atrial fibrillation on in-hospital mortality and to identify independent predictors of its development. A p value < 0.05 was considered significant. Results: We studied 6325 patients, and new-onset atrial fibrillation was found in 365 (5.8%). Reperfusion was successfully accomplished in both groups with no difference regarding type of reperfusion. In group 2, therapy with beta-blockers and angiotensin-conversion enzyme (ACE) inhibitors/angiotensin receptor blockers (ARBs) was less frequent, 20.6% received anticoagulation at discharge and 16.1% were on triple therapy. New-onset atrial fibrillation was associated with more in-hospital complications and mortality. However, it was not found as an independent predictor of in‑hospital mortality. We identified age, prior stroke, inferior myocardial infarction and complete atrioventricular block as independent predictors of new-onset atrial fibrillation. Conclusion: New-onset atrial fibrillation remains a frequent complication of myocardial infarction and is associated with higher rate of complications and in-hospital mortality. Age, prior stroke, inferior myocardial infarction and complete atrioventricular block were independent predictors of new onset atrial fibrillation. Only 36.7% of the patients received anticoagulation at discharge. (Arq Bras Cardiol. 2019; 113(5):948-957) Keywords: Atrial Fibrillation; ST Elevation Myocardial Infarction/complications; Hospitalization; Mortality; Antihypertensive; Anticoagulants. Introduction Atrial fibrillation (AF) is the most commonly encountered arrhythmia and often complicates acute myocardial infarction (AMI) with new-onset atrial fibrillation of 6–21%. 1 In this clinical setting, the occurrence of AF is significant, since rapid and irregular ventricular rates can further impair coronary circulation. The etiology of AF in this context, as in critical illnesses, is most likely multifactorial and includes ischemia, reduced atrial perfusion, glycolytic anaerobic pathways, inflammation, neurohumoral factors, autonomic regulation abnormalities, high left ventricular end-diastolic pressure and elevated atrial pressure. 2-4 The bulk of evidence demonstrates that AF in patients hospitalized for AMI represents an important challenge, concerning the role of antiarrhythmic drugs and antithrombotic treatment. 1,2 The development of AF is linked to poorer prognosis and adverse impact on in-hospital and long‑term mortality. 5,6 This seems to also apply for transient AF, which has reversed back to sinus rhythm at the time of discharge. With advancements in reperfusion strategies and contemporary treatment with angiotensin-conversion enzyme (ACE) inhibitors, statins and antiplatelet therapy, it could be anticipated that there would be a change in incidence and prognostic impact of AF in the setting of AMI. 2 The purpose of this study was to determine the incidence of AF in patients hospitalized for ST-segment elevation myocardial infarction (STEMI), identify predictors of AF development and analyze its impact on therapy and in-hospital mortality, in the setting of AMI managed according to the most recent guideline strategies. Methods We performed a multicenter retrospective cohort study and identified all hospital admissions fromOctober 2010 to August 2017 with primary discharge diagnosis of ST-segment elevation 948