Response by Fiol-Sala and Bayés de Luna to Letter Regarding Article, “Acute Coronary Syndrome: What Is the Affected Artery? Where Is the Occlusion Located? And How Important Is the Myocardial Mass Involved?”
We extend our thanks to Jin-shan and Xue-bin for the letter regarding our ECG Challenge published in Circulation,1 which has provided us with an opportunity to emphasize the importance of the correlation between ECG pattern and the projection of the ECG vector in the different hemifields of different leads.
Lead aVL (-30°) is nearly a mirror pattern of lead III (+120°). Therefore, in many cases when we have ST depression in inferior leads, especially lead III, ST elevation occurs in VL and vice versa. If ST depression is found in leads II, III, and VF, then we have clearer confirmation that the vector of transmural ischemia (we prefer transmural ischemia over than injury) points down (between +30° and +150°). However, if it points to ≈40° to 50°, it still remains in the positive hemifield of VL and may be recorded as isodiphasic or positive in this lead, despite the fact that it is downward, and thus it is recorded as positive in leads II, III, and VF. Therefore, we feel that, although VL may be useful in some cases, it is preferable to examine the ECG pattern in leads II, III, and VF to accurately locate the stenosis that is proximal or distal to the first diagonal branch of the left anterior descending coronary artery.
- © 2018 American Heart Association, Inc.