Background: The clinical significance of mildly elevated troponins in patients presenting to the emergency room (ER) with atrial fibrillation (AF) is not well understood.
Hypothesis: We hypothesized that mildly elevated troponin in these patients is associated with adverse cardiovascular outcomes.
Methods: In a multi-center, retrospective study, 662 patients with AF were divided into 3 groups based on troponin levels: group 1, mildly elevated; group 2, normal; and group 3, troponin not measured. Primary outcome was the combined endpoint of all-cause mortality and myocardial infarction (MI) at one year.
Results: Levels of TnI were measured in 503 (76%) patients. They were elevated in 220 patients (33%, group 1; mean, 0.56 ng/mL), normal in 283 patients (43%, group 2), and not measured in 159 patients (24%, group 3). Significantly more cardiac testing was done at index hospitalization in group 1 (50%) compared with groups 2 and 3 (28% and 29%, P ≤ 0.001) and in the following year (29%, vs 20% and 17%, P = 0.02). Group 1 had more positive tests (62%) compared with groups 2 and 3 (25% and 43%, P ≤ 0.001). Group 1 had a significantly higher occurrence of the primary endpoint (22%, vs 10% and 15%, P = 0.002), driven primarily by a higher incidence of MI in group 1 (7%, vs 1% and 2%, P = 0.001).
Conclusions: Troponin levels are routinely checked in a majority of patients presenting to the emergency department with AF. Even mildly elevated TnI is associated with a greater incidence of coronary artery disease on diagnostic testing and a higher 1-year incidence of MI.
© 2014 Wiley Periodicals, Inc.