Rapid atrial fibrillation (AF) is commonly associated with ST-segment depressions. ST-segment depression during a chest pain episode or exercise stress testing in sinus rhythm is predictive of obstructive coronary artery disease (CAD), but it is unclear if the presence or magnitude of ST-segment depression during rapid AF has similar predictive accuracy.

One hundred twenty-seven patients with rapid AF (heart rate ≥120 beats per minute) who had cardiac catheterization performed during the same hospital admission were retrospectively reviewed. Variables to compute thrombolysis in myocardial infarction (TIMI) risk score, demographic profiles, ST-segment deviation, cardiac catheterization results, and cardiac interventions were collected.

Thirty-five patients had ST-segment depression of 1 mm or more, and 92 had no or less than 1 mm ST depression. Thirty-one patients were found to have obstructive CAD. In the group with ST-segment depression, 11 (31%) patients had obstructive CAD and 24 (69%) did not. In the group with less than 1 mm ST-segment depression, 20 (22%) had obstructive CAD and 72 (78%) did not (P = .25). Sensitivity, specificity, and positive and negative predictive values for presence of obstructive CAD were 35%, 75%, 31%, and 78%, respectively. The presence of ST-segment depression of 1 mm or more was not associated with presence of obstructive CAD before or after adjustment of TIMI variables. The relationship between increasing grades of ST-segment depression and obstructive CAD showed a trend toward significance (P = .09), which did not persist after adjusting for TIMI risk variables (P = .36).

ST-segment depression during rapid AF is not predictive for the presence of obstructive CAD.