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

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.