New-onset or Pre-existing Atrial Fibrillation in Acute Coronary Syndromes: Two Distinct Phenomena With a Similar Prognosis

Abstract

Introduction and objectives: The management and risk stratification of patients with atrial fibrillation (AF) and acute coronary syndromes constitute a challenge. We aimed to evaluate the prognostic impact of AF whether present at admission or occurring during hospitalization for acute coronary syndromes, as well as trends in treatments and outcome.

Methods: Data derived from 35 958 patients enrolled between 2004 and 2015 in the AMIS Plus registry were retrospectively analyzed.

Results: Pre-existing AF (pre-AF) was present in 1644 (4.7%) while new-onset AF (new-AF) was evident in 309 (0.8%). Presentation with ST-segment elevation myocardial infarction and need for hemodynamic support was frequent in patients with AF, especially in those with new onset of the arrhythmia. A change of the medical and interventional approaches was observed with a progressive increase in oral anticoagulation prescription and referral for angiography and percutaneous coronary interventions in pre-AF patients. Despite different baseline risk profile and clinical presentations, both AF groups showed high in-hospital and 1-year mortality (in-hospital new-AF vs pre-AF [OR, 0.79; 95%CI, 0.53-1.17; P = .246]; 1-year mortality new-AF vs pre-AF [OR, 0.72; 95%CI, 0.31-1.67; P = .448]) Pre-AF but not new-AF independently predicted in-hospital mortality. While mortality declined over the study period for patients with pre-AF, it remained stable among new-AF patients.

Conclusions: While pre-AF is independently associated with in-hospital mortality, new-AF may reflect a worse hemodynamic impact of the acute coronary syndromes, with the latter ultimately driving the prognosis.

Keywords: Acute coronary syndrome; Atrial fibrillation; Fibrilación auricular; Infarto agudo de miocardio con elevación del segmento ST; Mortalidad; Mortality; ST-segment elevation myocardial infarction; Síndrome coronario agudo.