Correlation of remote ST segment depression and coronary anatomy during acute coronary occlusion

BACKGROUND: The appearance of remote ST segment depression (RSTD) on an ele ctrocardiogram (ECG) is associated with more extensive infarction and a wor se clinical outcome than when RSTD is absent. OBJECTIVE: To determine whether RSTD predicts coronary anatomy during acute coronary occlusion. It was hypothesized that RSTD is associated with the o cclusion of a proximal lesion, an extensive artery and an artery without di stal collateralization. PATIENTS AND METHODS: In 113 consecutive patients with single vessel diseas e undergoing percutaneous transluminal coronary angioplasty (PTCA), 12-lead ECGs (recorded at baseline and during balloon inflation) and angiographica l data were analyzed independently. Patients with ST segment elevation in t he primary territory and RSTD (greater than 1 mm ST depression at: 80 ms af ter the J point) (group A) were compared with patients without RSTD (group B). Proximal lesions were defined as lesions located in the segments proxim al to the acute marginal branch, first diagonal artery or first obtuse marg inal branch. An extensive right coronary artery (RCA) was one that supplied the posterolateral wall; an extensive left anterior descending (LAD) arter y was one that supplied the inferoapical wall; and an extensive circumflex artery was one that supplied the posterior descending artery. RESULTS: Fifty-four patients (48%) had PTCA of the proximal vessels, 43 pat ients (38%) had extensive target vessels and 11 patients (9.7%) had collate rals. Target lesions included 33% in RCA, 44% in LAD artery and 23% in circ umflex artery. Forty five patients (40%) developed RSTD during balloon infl ation (group A). Patients in group A were more likely to have extensive ves sels on the angiogram than those in group B (group A 49%, group B 31%; P=0. 05). None of the patients in group A had collaterals to the culprit artery, while 16% of patients in group B did (P=0.003). The two groups were not si gnificantly different with respect to the number of proximal lesions (group A 58%, group B 42%; P=0.08). Analysis performed according to the target ar tery revealed that RSTD was associated with occlusion of an extensive RCA d uring RCA occlusion (extensive RCA in group A 100%, group B 57%; P=0.006). For the LAD artery, RSTD was associated with proximal lesions (group A 74%, group B 41%; P=0.02) and absence of collaterals (group A 100%, group B 74% ; P=0.01). CONCLUSIONS: During acute coronary occlusion, the presence of RSTD on 12-le ad ECG was specific for the absence of collaterals. The presence of RSTD du ring RCA occlusion was strongly associated with an extensive RCA, suggestiv e of posterolateral wall ischemia. During LAD artery occlusion, the presenc e of RSTD was associated with proximal occlusion, which resulted in ischemi a of the LAD artery and the major diagonal artery territories.