[Deviation of ST-segment and detection of infarction related artery in patients with acute inferior wall infarction].

Objective: To explore the characteristics of ST-segment deviation in patients with acute ST elevation myocardial infarction(STEMI)having only one vessel lesion in either left circumflex artery (LCX) or right coronary artery (RCA).

Methods: All AMI (acute myocardial infarction) patients were admitted into Peking Union Medical College Hospital from January 1996 to March 2009. They underwent coronary angiography (CAG). And the IRA (infarction-related artery) was either LCX or RCA without other coronary artery stenosis. Their ST-segments deviations on electrocardiogram (ECG) were analyzed quantitatively.

Results: Among 2503 AMI cases undergoing CAG during hospitalization, 75 cases had LCX (n = 16) or RCA (n = 59)-related STEMI. The RCA group was further divided into the proximal subgroup (n = 21) and the distal subgroup (n = 38). RCA as IRA was diagnosed when ST I depression < 0, ST V(1) elevation ≥ 0 or ST I and aVL depression < 0 with the sensitivities of 55.9%, 74.6% and 54.2% and the specificities of 81.3%, 62.5% and 81.3% respectively. LCX as IRA was diagnosed when ST aVR depression ≥ 0.1 mv, ST I elevation ≥ 0 or ST V(5) and V(6) elevation ≥ 0 with the sensitivities of 68.8%, 81.3% and 31.3% and the specificities of 76.3%, 59.3% and 91.5% respectively. Proximal occlusion of RCA was diagnosed when there was no ST depression in V(1) and depression in V(2), Max precordial ST depression in V(1)-V(3) with the sensitivities of 47.6% and 52.4% and the specificities of 78.9% and 84.2%.

Conclusion: While discriminating IRA in STEMI patients with single LCX or RCA lesion, it is necessary to assess all ST-segments deviations on ECG.