Sections View Full Chapter Figures Tables Videos Annotate Full Chapter Figures Tables Videos Supplementary Content +++ ECG Findings ++ ST elevation in aVR ≥ 1 mm. ST elevation in V1 ≥ 1 mm is common as well. Widespread ST depression, typically in at least six to eight other leads. +++ Pearls ++ The left main coronary artery branches into the left anterior descending artery and the circumflex artery. It supplies blood to the ventricular septum and the anterior and lateral aspects of the left ventricle, usually sparing the posterior and inferior portion. Risk of cardiogenic shock is high since so much of the left ventricle is served by the left main coronary artery. Patients with a 100% LMCA occlusion often suffer a pre-hospital cardiac arrest and may present in cardiogenic shock. ST segment elevation in lead aVR may also be seen in severe triple vessel disease, proximal left anterior descending occlusion and diffuse subendocardial ischemia. Other causes of diffuse myocardial ischemia, such as aortic dissection or profound anemia, can also produce this ECG pattern. ST elevation in lead aVR is not specific for left main disease, as there are many other potential causes of this finding. ++ FIGURE 23.6A Left Main Coronary Artery Lesion. (ECG contributor: R. Jason Thurman, MD.) Graphic Jump LocationView Full Size||Download Slide (.ppt) ++ FIGURE 23.6B Significant ST elevation is present in lead aVR (upward arrow), and diffuse reciprocal ST depression is seen in multiple leads (downward arrows). Graphic Jump LocationView Full Size||Download Slide (.ppt) Your Access profile is currently affiliated with [InstitutionA] and is in the process of switching affiliations to [InstitutionB]. Please select how you would like to proceed. Keep the current affiliation with [InstitutionA] and continue with the Access profile sign in process Switch affiliation to [InstitutionB] and continue with the Access profile sign in process Get Free Access Through Your Institution Learn how to see if your library subscribes to McGraw Hill Medical products. Subscribe: Institutional or Individual Sign In Error: Incorrect UserName or Password Username Error: Please enter User Name Password Error: Please enter Password Sign in Forgot Password? Forgot Username? Download the Access App: iOS | Android Sign in via OpenAthens Sign in via Shibboleth You already have access! Please proceed to your institution's subscription. Create a free profile for additional features.