The electrocardiogram (EKG) remains an essential tool in the evaluation of patients with acute coronary syndromes (ACS). The role of the EKG in assessing the severity of the coronary artery disease (CAD) in patients with a Left Circumflex artery (LCX) related ACS has not been well established. We evaluated the usefulness of the EKG at presentation to predict the angiographic results in patients who underwent emergent percutaneous coronary intervention (PCI) for a LCX related ACS.
Design: Retrospective chart review. Subjects: All documented LCX related ACS that underwent emergent PCI to the LCX between January 2001 and December 2002. Exclusion criteria: Elective PCI, thrombolytic therapy, PCI to multiple vessels, and history of coronary artery bypass graft. Patients were divided in two groups according to their EKG at admission: ischemic (T-wave inversion, ST-segment depression or elevation, left bundle branch block) and non-ischemic. Study outcomes: evidence of occlusive disease (OD) in the culprit vessel (TIMI flow 0-1), and severity of CAD in the remaining coronary arteries (Friesinger Index -FI).
Of the 62 study patients, 36 (58.1%) had ischemic EKGs (T-wave inversion 21%, ST-segment depression 17.7%, ST-segment elevation 19.4%). Nineteen of 36 (53%) patients with ischemic EKGs had TIMI flow 0-1, compared to 14 of 26 (54%) in the non-ischemic EKG group (p=0.93). The sensitivity and specificity of an ischemic EKG for OD were 58% (95%CI, 39% to 75%) and 41% (95%CI, 24% to 61%), respectively. The positive likelihood ratio (LR) was 0.98 (pre-test probability=53%, post-test probability=52%), and the negative LR was 1.02 (pre-test probability=53%, post-test probability=53%). The mean values of the FI were similar in the ischemic (8.8) and non-ischemic (8.3) EKG groups, with a difference between the mean of 0.5 (95% CI: -0.6 to 1.6; p=0.38).
In patients with LCX related ACS, the EKG was not useful in predicting the severity of the underlying CAD in the culprit vessel or in the remaining coronary arteries.
A non-ischemic EKG should not deter PCI when otherwise clinically indicated.
D. Moguillansky, None.