chapter Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ Left Bundle Branch Block and Acute MI 11 Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ

Chapter 11 Objectives Describe the diagnostic problems with LBBB Describe the criteria for AMI in LBBB using QRS changes Use a simple table ECG calculator to determine the probability of an AMI in LBBB 116

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ Left Bundle Branch Block Use Lead V1 (MCL-1) QRS >120 ms Circle the J point Draw the line Use your turn signal ST elevation due to late repolarization 117

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ LBBB and AMI LBBB has higher mortality than RBBB Most often seen in anterior MI Higher mortality if not treated Mortality rate reduced if treated in less than 6 hours 118

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ LBBB Hemodynamics QRS >170 ms has ejection fraction of EJ <50% (60–75% normal) Left ventricular end diastolic pressure is higher LV function poorer

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ Criteria for AMI in LBBB New onset of LBBB Get an old one if available Facilitate the search Suggestive history and physical exam

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ Changes in QRS Q waves in at least 2 lateral leads

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ ECG Criteria R wave regression in leads V1–V4 118

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ ECG Criteria Late notching of S wave in at least 2 leads V3–V5

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ ECG Criteria AMI LBBB calculator Sgarbossa, Pinski, Barbagetata, et al. Hot new data that is easy to use ST elevation and depression Diagnostic quality is necessary 119

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ LBBB and AMI Calculator 119

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ AMI in LBBB Calculator Is the ST elevation >1 mm and concordant with the QRS axis? 120

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ AMI / LBBB Calculator ST segment depression ≥1 mm in Leads V1, V2, or V3?

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ AMI / LBBB Calculator ST elevation ≥5 mm discordant from the QRS axis?

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ Reliability of the Calculator Specificity Sensitivity

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ Practice Cases AMI and LBBB 121

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ 121

Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ

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