RJS ECG Case Series InterpretationSinus rhythm at 85/min with left axis deviation.Wide spread ST segment depression involving leads II, III,aVF, and V2-V6 (with associated T wave inversion in leadsIII, aVF, and V3-V6).ST segment elevation in leads aVR and V1.Taken together, these finding are suggestive of diffusesubendocardial myocardial ischemia/infarction (NSTEMI)With the lead aVR showing elevation of the ST segment,the presence of a significant lesion in the left main coronaryartery or its equivalent (critical lesions in the proximal portion of bothLAD and LCx) should be entertained. In addition, due to inferior leadinvolvement, RCA is likely to be also affected.
Brief Hx and Physical FindingsThis 62-yr-old man was brought to the ER because of having severechest tightness of sudden onset, lasting for about 30 min. Reportedly,he had experienced intermittent episodes of chest tightness like thisone not related to exertion for one year. About one week before thisadmission, the frequency of these episodes had increased from 2-3 to4-5/week.Past medical Hx was significant for DM and hypertension for morethan 10 years and ESRD presumably due to diabetic nephropathy forwhich he had been on peritoneal dialysis for one and a half years.Additionally, he had one episode of TIA that had occurredapproximately one year prior. On PE, he was obese, in no respiratorydistress. BP measured 110/70 mmHg, PR 80/min and regular, and RR16/min. The lungs were clear. The PMI of the heart was not visible.There was a loud S4 but there were no murmurs.
Chest X-rayThere is no significant cardiomegaly.The lung markings are slightly increasedin both lower lung fields.Bilateral costophrenic angles are clearlyidentified.
Pertinent Laboratory Data Cardiac Enzymes CK CKMB Troponin -I4/22 165 10.0 0.4120:284/22 252 21.5 8.523:59
Mechanism of ST-segment Elevation in aVRLead aVR is referred to as the cavitary lead, electricallyopposite to leads I, II, aVL and V4-6; ST elevation (STE) inaVR may therefore represent a reciprocal change inresponse to ST depression in these leads. Additionally,Lead aVR also directly records electrical activities fromthe RV outflow tract and the basal portion of theinterventricular septum. Consequently, STE in aVR canresult from (a) diffuse subendocardial ischaemia(reciprocal change) or transmural ischaemia/infarction ofthe basal interventricular septum (e.g. due to a proximalocclusion within the left coronary artery system)
Take-Home Message• The ECG findings suggestive of significant LMCA are widespread horizontal ST depression, most prominent in leads I, II and V4-6; ST elevation in aVR ≥ 1mm; and ST elevation in aVR ≥ V1.• However, ST elevation in aVR is not entirely specific to LMCA occlusion. It may also be seen with proximal LAD occlusion and severe triple vessel CAD.• ST elevation in aVR ≥ 1 mm is a strong predictor of severe LMCA /triple vessel CAD requiring CABG. Kosuge M, et al. An early and simple predictor of severe left main and/or three-vessel disease in patients with non-ST-segment elevation acute coronary syndrome. Am J Cardiol. 107:495-500, 2011.
AcknolwledgmentThe Case was provided by Int 王昇元 / VS 張盛雄 at MacKay Memorial Hospital, Taipei2012-04-28