Transcript Chapter 11
11 chapter Left Bundle Branch Block and Acute MI Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ 116 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 Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ 117 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 Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ 118 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 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 118 ECG Criteria • R wave regression in leads V1–V4 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 119 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 Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ 119 LBBB and AMI Calculator Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ 120 AMI in LBBB Calculator • Is the ST elevation >1 mm and concordant with the QRS axis? 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 121 Practice Cases AMI and LBBB 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 Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ 122 Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ 123 Page, 12-Lead ECG for Acute and Critical Care Providers © 2006 by Pearson Education, Inc. Upper Saddle River, NJ