Clinical utility and prognostic significance of measuring troponin I levels in patients presenting to the emergency room with atrial fibrillation.
BACKGROUND
The clinical significance of mildly elevated troponins in patients presenting to the emergency room (ER) with atrial fibrillation (AF) is not well understood.


OBJECTIVE
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.
Division of Cardiovascular Diseases Cardiovascular Research Institute, University of Kansas Medical Center and Hospital, Kansas City, Kansas.
Kamal
K
Gupta
Jayasree
J
Pillarisetti
Mazda
M
Biria
Micah
M
Pescetto
Tareq M
TM
Abu-Salah
Chandra
C
Annapureddy
Kay
K
Ryschon
Buddhadeb
B
Dawn
Dhanunjaya
D
Lakkireddy
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001281:Atrial Fibrillation / Q000097:blood*; D015415:Biomarkers; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000401:mortality; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D019210:Troponin I / Q000097:blood*; D055815:Young Adult
D015415:Biomarkers; D019210:Troponin I