Detection of acute coronary occlusion in patients with acute coronary syndromes presenting with isolated ST-segment depression.

OBJECTIVES: This study sought to determine whether 80-lead body surface potential mapping (BSPM) would improve detection of acute myocardial infarction (AMI) and occluded culprit artery in patients presenting with ST-segment depression (STD) only on 12-lead ECG.

BACKGROUND: In patients with acute coronary syndromes (ACS), the standard 12-lead ECG has limited sensitivity (50-60%) for AMI.

METHODS: Consecutive patients presenting pre- and in-hospital between 2000 and 2006 with acute ischaemic-type chest pain and an initial 12-lead ECG with STD only of ≥ 0.05 mV in two or more contiguous leads were analysed. Flow in the culprit artery at angiography was graded using the TIMI flow grade (TFG) criteria.

RESULTS: Enrolled were 410 patients: of these, 240 (59%) had an occluded culprit artery (TFG 0/1) with AMI, 80 (19%) had a patent culprit artery (TFG 2/3) with AMI, 67 (16%) had TFG 2/3 with cardiac troponin T (cTnT) <0.03 µg/l, and 23 (6%) had TFG 0/1 with cTnT < 0.03 µg/l. BSPM ST-segment elevation (STE) occurred in 267 (65%) patients. For the diagnosis of TFG 0/1 in the culprit artery and AMI, BSPM STE had sensitivity 91% and specificity 72% with STE occurring most commonly in the posterior territory (60%). Patients with TFG 0/1 and AMI were significantly more likely to suffer death or nonfatal MI at 30 days than those with TFG 2/3 and cTnT < 0.03 µg/l (adjusted hazard ratio 4.12, 95% CI 1.67-8.56, p = 0.003).

CONCLUSION: Among 410 ACS patients presenting with only STD, BSPM identifies STE beyond the territory of the 12-lead ECG with sensitivity 91% and specificity 72% for diagnosis of occluded culprit artery with AMI.