Disclosures: � 12-Lead EKG Interpretation � • I work for Virginia Garcia � Memorial Health Center, � Beaverton, Oregon. � Jon Tardiff, BS, PA-C � • And I am a medical editor for Jones & Bartlett Publishing. � ��������������������������������� � Goals for today’s ECG Review: � What a 12-Lead EKG can help you do � • Determine Right vs Left bundle branch block � • Diagnose Acute MI � • Diagnose ACS / AMI � • Diagnose old MI � • Interpret arrhythmias * (computer Dx) � • Location of the infarct � • Identify life-threatening syndromes (WPW, • Other Acute Coronary Syndromes � LGL, Long QT synd., Wellens synd., etc) � • Determine Axis � • Infer electrolyte imbalances � • Other ECG confounders � • Infer hypertrophy of any chamber � • Pfun! � • Infer COPD, pericarditis, drug effects, and more! � “Ask questions any time—I like answering them” � 3 �
������������ 73 y.o. male with nausea, syncope � Acute Inferior MI � ST elevation � 5 � 6 � (look at V1 for P waves) � What rhythm? �������������� (w/septal MI?) � ����������������������������������������� �
� another example… � WPW with Atrial Fib 9 � 10 � � Wolff-Parkinson-White synd. � WPW Graphic � Same pt, converted to SR • short PR � • wide QRS � • delta wave � 12 �
Limitations of a 12-Lead ECG � The Problem with Bundle Branch Blocks � • Truly useful only ~40% of the time � • Each ECG is only a 10 sec. snapshot � • Desynchronized contraction of the ventricles � • Serial ECGs are necessary, especially for ACS � • Reduced cardiac output � • Worsened heart failure � • Other labs help corroborate ECG findings (cardiac markers, Cx X-ray) � • ������������������������������������� � ���������������������������������� � • Confounders must be ruled out (dissecting aneurysm, pericarditis, WPW, LBBB, digoxin, RVH) � Confounder: Left Bundle Branch Block � Bundle Branch Blocks (QRS > 120 msec.) (right-sided lead) (left-sided lead) V1 R’ notch I r S Left BBB Right BBB (L I, V5, V6: (V1, V2, MCL1: upright QRS rsR’ pattern) with a notch) 15 � 16 � ������������������������������������� �
Bundle Branch Blocks Two QRSs RBBB � Blocked Healthy bundle � ventricle � V 1 & V 2 � V1 slur R’ notch I I r 17 � S LBBB � Practice: Bundle Branch Block � V 5 V 6 � ( & I, aVL) � 20 �
Which Bundle Branch is Blocked? � 1 � 1 � Right Bundle Branch Block (Lead V1) � � � RBBB RBBB Which Bundle Branch is Blocked? � 2 � 2 � Left Bundle Branch Block � LBBB 12-Lead � LBBB 12-Lead � (L I, V5, V6) �
Where is the Pathology? � Right Bundle Branch Block � Where is the Pathology? � Left Bundle Branch Block � 27 � 28 �
Limitations of a 12-Lead ECG � Impending AMI with ������� ECG! � • They are occasionally wrong! � 30 � ECG Pearls � • Lead II is the easiest lead to read / most intuitive � 13 hrs later — Acute Anterior MI � • But Lead V1 is our single best lead. � • “A Q in III is free.” (isolated Q in L III) � • If you know where the + electrode is, you can read any ECG � Elevated ST segments � • ������������������������������������������ � 31 �
ECG Lead Placement � & � Limb Leads � Electrophysiology Review � � I (standard � II leads) � III - � ± � + � 33 � 34 � � Normal 12-Lead ECG Leads I, II, III � I III II 35 �
Rapid Interpretation Tips � Dr. Willem Einthoven � • Invented the electrocardiograph � • Discovered atrial ������������ � • Won Nobel Prize for Medicine 1924 � 37 � Conduction System � Lead II � P wave axis � …upright in L II � II � R � T � P � U � R � Q � S � R wave axis � …upright in L II � SA Node AV Node His Bundle BBs Purkinje Fibers � 39 � 39 � 40 � Q � S �
Intervals � II � ������������������ � ��������� � � � 300, 150, 100, � Count PQRST in a 6- second strip & multiply x 10 � 75, 60, 50 � Easy, & more accurate � Quick, easy, sufficient PR � 300 150 100 75 60 6 seconds QRS � QT � PR Interval: 120 – 200 mSec (3 – 5 boxes) � QRS width: 60 – 120 mSec (1 � – 3 boxes) � QT/QTc interval: 400 mSec (10 boxes) � Horizontal axis is ���� (mS); vertical axis is electrical ������ (mV) � 41 � 41 � 42 � Normal Sinus Rhythm � 6 seconds Limb (frontal plane) Leads � � I (standard � II leads) � III � aVR � aVL (augmented leads) � aVF � What is the heart rate? 43 � 44 �
6 Frontal Plane Leads � Normal 12-Lead ECG (limb leads) � I III II L F R 46 � ������������������������������������������������������������ � � Axis Leads � - � I � II � III � aVR * � aVL � aVF � 47 � 48 �
Limb (frontal Chest (precordial) plane) Leads � Leads � � I � V1 (standard (anterior � II � V2 leads) leads) � III � V3 � aVR � V4 � aVL � V5 (lateral � aVF � V6 leads) (augmented leads) 49 � 50 � V Lead Progression � V Lead Cutaway �
New 12-Lead ECG Format � � Normal 12-Lead ECG aVL � II � aVF � I � -aVR � III � 54 � New 12-Lead ECG Format � � Axis Determination New � II � aVL � aVF � I � Old � -aVR � III �
Axis Deviation � Why We Care About Axis Deviations � Horizontal heart (0°): obesity, � The axis shifts ������������������� � 3 rd trimester pregnancy. Ascites � & �������������������� � Vertical heart (90°): slender build � Left Axis Deviation : LBBB, � Anterior MI, Inferior MI, Left � anterior hemiblock, LVH � Right Axis Deviation : Anterior � ��������������������������� � MI, Lateral MI, RBBB, COPD, � RVH, Left posterior hemiblock � Extreme RAD : Ectopic rhythm � (VT), massive MI � 57 � 58 � QRS Morphology in Lead II � How to calculate Axis � ��������� the computer does it for you! � ���� �� ����������������������� � (if tallest is Lead II = ����������� ) � 60 � II � �������� �� Thumbs up / Thumbs down � 59 �
3 � Practice: Axis � ������������������ Thumbs Up / Down Method � I � Lead I —Your Left thumb � Lead aVF —Your Right thumb � F � 61 � 62 � 4 � 1 � Axis Practice � Normal Axis � I � I � F � F � 63 � 64 �
4 � 5 � Left Axis Deviation � I � F � 65 � 66 � 5 � 6 � Right Axis Deviation � 67 � 68 �
6 � Lots of ways to read EKGs… � Extreme Right Axis Deviation � • QRSs wide or narrow? � • Sinus rhythm or not? � • Regular or irregular? � • If not, is it atrial fibrillation? � • Fast or slow? � • BBB? � • P waves? � • MI? � Symptoms: � • Syncope is bradycardia, heart blocks, or VT � • Rapid heart beat is AF, SVT, or VT � 69 � Rapid Interpretation Tips � Step-by-step method for reading a 12-Lead � Rapid Interpretation Tips � • Identify the rhythm. If supraventricular* , � If no LBBB, � � If present, � • Rule out other confounders: WPW, pericarditis, LVH, digoxin effect � • Identify location of infarct, and consider appropriate treatments: MONA, PCI [or fibrinolytic], nitrate infusion, heparin infusion, GP IIb, IIIa inhibitor, beta- blocker, clopidogrel, statin, etc. � 71 �
� Normal 12-Lead ECG Supraventricular rhythms � • Sinus rhythm � • Atrial fibrillation � • Junctional rhythm � • PSVT / AVNRT � • Atrial tachycardia � • Atrial flutter � • Wandering atrial pacemaker � • MAT � Rapid Interpretation Tips � Rapid Interpretation Tips � Rapid Interpretation Tips � Rapid Interpretation Tips � • Identify the rhythm. If supraventricular, � • Identify the rhythm. If supraventricular, � If no LBBB, � • Rule out left bundle branch block. If no LBBB, � • Check for: ST elevation, or ST depression with T wave inversion, and/or pathologic Q waves . � � If present, � � If present, � • Rule out other confounders: WPW, pericarditis, LVH, • Rule out other confounders: WPW, pericarditis, LVH, digoxin effect � digoxin effect � • Identify location of infarct, and consider appropriate • Identify location of infarct, and consider appropriate treatments: MONA, PCI [or fibrinolytic], nitrate treatments: MONA, PCI [or fibrinolytic], nitrate infusion, heparin infusion, GP IIb, IIIa inhibitor, beta- infusion, heparin infusion, GP IIb, IIIa inhibitor, beta- blocker, clopidogrel, statin, etc. � blocker, clopidogrel, statin, etc. �
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