Effect of new versus known versus no atrial fibrillation on 30-day and 10-year mortality in patients with acute coronary syndrome.

Coronary artery disease promotes the development of atrial fibrillation (AF). The aim of this study was to determine short- and long-term mortality in patients with acute coronary syndromes (ACS) and AF, depending on the AF presentation. A total of 2,335 consecutive patients with ACS were included. AF was classified as known persistent or permanent AF, known paroxysmal AF, new AF at admission, and new AF during hospitalization for ACS. Four hundred forty-two patients had any AF: 54 with known persistent or permanent AF, 150 with known paroxysmal AF, 54 with new AF at admission, and 184 with new AF during hospitalization. Statistically significant differences among subgroups related to previous heart failure (p <0.0001), stroke (p = 0.04), myocardial infarction (p <0.0001), angina pectoris (p <0.0001), hypercholesterolemia (p = 0.007), coronary artery bypass grafting (p <0.0001), and percutaneous coronary intervention (p = 0.03) were observed. Thirty-day mortality differed among the subgroups (p = 0.02) and was lowest in patients with known paroxysmal AF (7.3%). Ten-year mortality ranged from 53% to 78% among the subgroups. There were 5 predictors of long-term mortality across the subgroups: age (hazard ratio [HR] 1.06, 95% confidence interval [CI] 1.04 to 1.09, p <0.0001), previous myocardial infarction (HR 1.4, 95% CI 1.0 to 1.8, p = 0.04), heart failure (HR 1.8, 95% CI 1.3 to 2.4, p = 0.0002), diabetes (HR 1.7, 95% CI 1.2 to 2.2, p = 0.0005), and smoking (HR 1.7, 95% CI 1.2 to 2.3, p = 0.001). In conclusion, patient characteristics and 30-day mortality differed significantly among the subgroups, but long-term mortality did not. Any AF associated with ACS almost doubled the long-term mortality risk. AF in patients with ACS should therefore be regarded as an important risk factor irrespective of its presentation.