Electrocardiographic ST-segment monitoring during controlled occlusion of coronary arteries.

Background: Ischemia monitoring cannot always be performed by 12-lead ECG. Hence, the individual performance of the ECG leads is crucial. No experimental data on the ECG's specificity for transient ischemia exist.
Methods: In 45 patients a 19-lead ECG was registered during a 1-minute balloon occlusion of a coronary artery (left anterior descending artery [LAD], right coronary artery [RCA] or left circumflex artery [LCX]). ST-segment shifts and sensitivity/specificity of the leads were measured.
Results: During LAD occlusion, V3 showed maximal ST-segment elevation (0.26mV [IQR 0.16-0.33mV], p=0.001) and sensitivity/specificity (88% and 80%). During RCA occlusion, III showed maximal ST-elevation (0.2mV [IQR 0.09-0.26mV], p=0.004), aVF had the best sensitivity/specificity (85% and 68%). During LCX occlusion, V6 showed maximal ST-segment elevation (0.04mV [IQR 0.02-0.14mV], p=0.005), and sensitivity/specificity was (31%/92%) but could be improved (63%/72%) using an optimized cut-off for ischemia.
Conclusion: V3, aVF and V6 show the best performance to detect transient ischemia.
(© 2013.)