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Beyond Left Bundle Branch Block

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A patient in their 80s with a history of atrial fibrillation, hypertension, and hyperlipidemia presented to a rural hospital with sudden-onset chest pain and shortness of breath. For the prior few weeks, the patient had had intermittent chest pain that resolved with rest but was now persistent. The patient had no history of coronary artery disease (CAD). The physical examination was notable for tachycardia, 3/6 mid systolic ejection murmur, and significant pedal edema. An electrocardiogram (ECG) was obtained (Figure).

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The aVR lead of the ECG has historically been ignored.1 However, it is helpful in the diagnosis and prognosis of many clinical situations, including acute coronary syndrome, left ventricular aneurysm, Takotsubo syndrome, supraventricular and wide-complex tachycardias, Brugada syndrome, pericarditis, tricyclic toxic effects, and pulmonary embolus.1,2

An STE in lead aVR with diffuse STD (sometimes called the aVR sign) may indicate severe left main stenosis or multivessel CAD. The higher the STE in aVR, the higher the mortality.3 An AMI due to severe proximal LAD stenosis may cause STE in aVR; however, STE in V1 will exceed that in aVR, and diffuse STD is less common. This patient’s ECG may be similar to a variant type of inferior myocardial infarction reported by Aslanger et al.4 The pattern includes STE in lead III (but not leads I or II) along with STE in aVR and lateral STD in the presence of severe multivessel CAD. However, in the variant pattern described by Aslanger et al,4 STD is absent in lead V2, but it was present in this patient. The etiology for the STE in aVR was probably either reciprocal changes caused by STD in the anterolateral leads and/or infarction of the basal septum.

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Article Information

Corresponding Author: Mazen M. Kawji, MD, St Margaret's Health, 925 West St, Peru, IL 61354 (muhamed.m.kawji@osfhealthcare.org).

Published Online: July 25, 2022. doi:10.1001/jamainternmed.2022.2804

Conflict of Interest Disclosures: None reported.

Additional Contributions: We thank Victoria O’Brien Martian, the electrocardiogram technician who helped us acquire the electrocardiogram for this patient. She was not compensated for her contributions.

References
1.
Gorgels  APM , Engelen  DJM , Wellens  HJJ .  Lead aVR, a mostly ignored but very valuable lead in clinical electrocardiography.   J Am Coll Cardiol. 2001;38(5):1355-1356. doi:10.1016/S0735-1097(01)01564-9PubMedGoogle ScholarCrossref
2.
Chenniappan  M , Sankar  RU , Saravanan  K .  Lead aVR—the neglected lead.   J Assoc Physicians India. 2013;61(9):650-654.PubMedGoogle Scholar
3.
Yamaji  H , Iwasaki  K , Kusachi  S ,  et al.  Prediction of acute left main coronary artery obstruction by 12-lead electrocardiography. ST segment elevation in lead aVR with less ST segment elevation in lead V(1).   J Am Coll Cardiol. 2001;38(5):1348-1354. doi:10.1016/S0735-1097(01)01563-7PubMedGoogle ScholarCrossref
4.
Aslanger  E , Yıldırımtürk  Ö , Şimşek  B ,  et al.  A new electrocardiographic pattern indicating inferior myocardial infarction.   J Electrocardiol. 2020;61:41-46. doi:10.1016/j.jelectrocard.2020.04.008PubMedGoogle ScholarCrossref
5.
Sgarbossa  EB , Pinski  SL , Barbagelata  A ,  et al.  Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block. GUSTO-1 (Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries) Investigators.   N Engl J Med. 1996;334(8):481-487. doi:10.1056/NEJM199602223340801PubMedGoogle ScholarCrossref
6.
Smith  SW , Dodd  KW , Henry  TD , Dvorak  DM , Pearce  LA .  Diagnosis of ST-elevation myocardial infarction in the presence of left bundle branch block with the ST-elevation to S-wave ratio in a modified Sgarbossa rule.   Ann Emerg Med. 2012;60(6):766-776. doi:10.1016/j.annemergmed.2012.07.119PubMedGoogle ScholarCrossref
7.
Di Marco  A , Rodriguez  M , Cinca  J ,  et al.  New electrocardiographic algorithm for the diagnosis of acute myocardial infarction in patients with left bundle branch block.   J Am Heart Assoc. 2020;9(14):e015573. doi:10.1161/JAHA.119.015573PubMedGoogle ScholarCrossref
8.
Kawji  MM , Glancy  DL .  Repeat the electrocardiogram!   Am J Cardiol. 2017;119(5):816-817. doi:10.1016/j.amjcard.2016.11.014PubMedGoogle ScholarCrossref
9.
Kawji  MM , Glancy  DL .  Inferior Q waves and left bundle branch block.   Am J Cardiol. 2015;116(5):822-823. doi:10.1016/j.amjcard.2015.05.056PubMedGoogle ScholarCrossref
10.
Horan  LG , Flowers  NC , Tolleson  WJ .  Thomas JR: the significance of diagnostic Q waves in the presence of bundle branch block.   Chest. 1970;58(3):214-220. doi:10.1378/chest.58.3.214PubMedGoogle ScholarCrossref
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