De novo and pre-existing atrial fibrillation in acute coronary syndromes: impact on prognosis and cardiovascular events in long-term follow-up

The aim of the study was to compare in-hospital and long-term prognosis in patients with acute coronary syndromes (ACS) and de novo vs. pre-existing atrial fibrillation (AF). Atrial fibrillation increases the risk of serious adverse events including death in patients with ACS. However, it is unclear whether de novo and pre-existing AF portend a different risk.

We analysed the incidence, clinical characteristics, and in-hospital and long-term outcomes in patients with AF and ACS based on combined data from Polish Registry of Acute Coronary Syndrome (PL-ACS) (n = 581 843) and SILICARD (n = 852 063) databases. Atrial fibrillation at admission was diagnosed in of 6.16% patients [de novo: 1129 (2.46%); pre-existing: 1691 (3.7%)]. Groups were compared (N = 1023 vs. 1023) after matching for relevant clinical factors. De novo and pre-existing AF differed in in-hospital diuretic (52% vs. 58%; P = 0.008) and aldosterone inhibitor (27.5% vs. 32.5%; P = 0.02) use, Thrombolysis In Myocardial Infarction (TIMI) flow before percutaneous coronary intervention (P = 0.016), and diuretic (52.1% vs. 58%; P = 0.008) and oral anticoagulant (27.5% vs. 32.5%; P = 0.018) use at discharge. In-hospital mortality in the de novo AF group was significantly higher (13.1% vs. 8.31%; P = 0.0005). Post-discharge 12-month survival was similar between groups (14.5% vs. 15.3%, P = 0.63). Long-term re-hospitalization due to heart failure (22.7% vs. 17.2%; P < 0.005) and medical contact due to AF (48.4% vs. 26.1%, P < 0.0001) rates were higher in the group with pre-existing AF, without the difference of stroke or myocardial infarction occurrence.

De novo AF accounts for 40% of all AF cases in ACS patients and is an unfavourable in-hospital prognostic factor. The occurrence of de novo AF during ACS should require special attention and caution in the treatment of these patients.