Rapid 12-Lead EKG Interpretation jontardiff@aol.com Jon Tardiff, BS, PA-C OHSU Clinical Assistant Professor What a 12-Lead EKG can help you do Diagnose ACS / AMI Interpret arrhythmias (computer Dx) Identify life-threatening syndromes (WPW, LGL, Long QT synd., Wellens synd., etc) Infer electrolyte imbalances Infer hypertrophy of any chamber Infer COPD, pericarditis, drug effects, and more! Disclosures: I work for Virginia Garcia Memorial Health Center. And I am a medical editor for Jones & Bartlett Publishing. For example: 73 y.o. male with nausea, syncope 5 Goals for today s ECG Review: Determine Right vs Left bundle branch block Diagnose Acute MI Diagnose old MI Location of the infarct Other Acute Coronary Syndromes Other ECG confounders Determine Axis Pfun! 3 Acute Inferior MI ST elevation 6
What rhythm? (look at V1 for P waves) WPW with Atrial Fib 10 Atrial flutter (w/septal MI?) The flutter waves are invisible in Lead II WPW Graphic Wolff-Parkinson-White synd. short PR wide QRS delta wave another example 9 Same pt, converted to SR 12
Limitations of a 12-Lead ECG Truly useful only ~40% of the time Each ECG is only a 10 sec. snapshot Serial ECGs are necessary, especially for ACS Other labs help corroborate ECG findings (cardiac markers, Cx X-ray) Confounders must be ruled out (dissecting aneurysm, pericarditis, WPW, LBBB, digoxin, RVH) 13 hrs later Acute Anterior MI Elevated ST segments 16 Confounder: Left Bundle Branch Block Impending AMI with normal ECG! 14 15 Confounder: Wolff-Parkinson-White syndrome ECG Pearls Pt is a 4 y.o. child w/ one episode of tachycardia and shortness of breath. WPW mimicking MI (false Q waves in Lead II, III, AVF, V1, & V3). Also mimicking LBBB. Lead II is the easiest lead to read / most intuitive But Lead V1 is our single best lead. Lead V3 is best for QT interval measurement A Q in III is free. (isolated Q in L III) 80% of reading an ECG is finding the P wave! The other half is knowing where the + electrode is.
Dr. Willem Einthoven ECG Lead Placement & Electrophysiology Review Rapid Interpretation tion Tips 22 Limb Leads I II III (standard leads) - ± 20 + Conduction System II R P T Q S SA Node AV Node His Bundle BBs Purkinje Fibers 23 U Normal 12-Lead ECG Lead II P wave axis upright in L II R R wave axis upright in L II Q S 24 19
QRS Morphology in Lead II Leads I, II, III I II III II 26 Normal Sinus Rhythm Triplicate Method: 6-second : 6 seconds 300, 150, 100, 75, 60, 50 Quick, easy, sufficient Count PQRST in a 6- second strip & multiply x 10 Easy, & more accurate 300 150 100 75 60 6 seconds What is the heart rate? Horizontal axis is time (ms); vertical axis is electrical energy 28 (mv) 29 Intervals II PR QRS QT PR Interval: 120 200 msec (3 5 boxes) QRS width: 60 120 msec (1½ 3 boxes) QT/QTc interval: 400 msec (10 boxes) Limb (frontal plane) Leads I II III avr avl avf (standard leads) (augmented leads) 27 30 25
Normal 12-Lead ECG 6 Frontal Plane Leads (limb leads) I II III L R F 32 Limb (frontal plane) Leads Chest (precordial) Leads I II III avr avl avf (standard leads) V1 V2 V3 V4 V5 V6 (anterior leads) (lateral leads) (augmented leads) 34 35 - Axis Leads I II III avr* avl avf 33 36
V Lead Cutaway V Lead Progression Lots of ways to read EKGs QRSs wide or narrow? Regular or irregular? Fast or slow? P waves? Sinus rhythm or not? If not, is it atrial fibrillation? BBB? MI? Step-by-step method for reading a 12-Lead Symptoms: Syncope is bradycardia, heart blocks, or VT Rapid heart beat is AF, SVT, or VT 41 Normal 12-Lead ECG Rapid Interpretation Tips 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, betablocker, clopidogrel, statin, etc.
Supraventricular rhythms Sinus rhythm Atrial fibrillation Junctional rhythm PSVT / AVNRT Atrial tachycardia Atrial flutter Wandering atrial pacemaker MAT The Problem with Bundle Branch Blocks Desynchronized contraction of the ventricles Reduced cardiac output Worsened heart failure LBBB confounds the EKG interpretation and makes it harder to find ACS Normal 12-Lead ECG Bundle Branch Blocks (QRS > 0.12 sec.) (right-sided lead) (left-sided lead) V1 R r I notch S Right BBB (V1, V2, MCL1: rsr pattern) Left BBB (L I, V5, V6: upright QRS with a notch) 47 Rapid Interpretation Tips 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, betablocker, clopidogrel, statin, etc. Bundle Branch Blocks Two QRSs Healthy ventricle Blocked bundle V1 R notch slur r I I S 48
RBBB V 1 & V 2 Which Bundle Branch is Blocked? 1 RBBB LBBB V 5 V 6 (& I, avl) Right Bundle Branch Block (Lead V1) 1 RBBB Practice: Bundle Branch Block 51 Which Bundle Branch is Blocked? 2 LBBB 12-Lead
Left LBBB Bundle 12-Lead Branch Block (L I, V5, V6) Where is the Pathology? 58 2 Where is the Pathology? Right Bundle Branch Block Left Bundle Branch Block Axis Determination 59
Why We Care About Axis Deviations The axis shifts towards hypertrophy & away from infarction Calculating Axis: Thumbs Up / Down Method Lead I Your Left thumb Lead avf Your Right thumb 64 I Axis Deviation Horizontal heart (0 ): obesity, 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 62 (VT), MI Practice: Axis 3 F 65 I How to calculate Axis Easiest: the computer does it for you! Easy: find the tallest R wave (if tallest is Lead II = normal axis) Even easier: (if Lead II is upright = normal axis 63 Funnest: Thumbs up / Thumbs down Axis Practice Normal Axis 1 F 66 61
I F 4 5 Right Axis Deviation 70 I F 4 Left Axis Deviation 68 6 71 69 Extreme Right Axis Deviation 72 5 6 67
New 12-Lead ECG Format avl II I avf -avr III ST elevation, ST depression, T wave inversion, pathologic Q waves STEMI Normal Ischemia Injury Infarction avl I -avr New 12-Lead ECG Format II avf III New Old 77 Rapid Interpretation Tips Rapid Interpretation Tips Identify the rhythm. If supraventricular, 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, 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, betablocker, clopidogrel, statin, etc. 73
Percutaneous Coronary Intervention MI ECG Patterns RCA before and after stenting Before stenting After stenting 80 Why Pathologic Q Waves Form Normal q Pathologic Q 83 STEMI: ECG Changes (normal) (w/onset cx pn) (20 minutes) (1 hour) (>1 hr) (1 week years) A. Normal ECG B. Hyperacute T wave changes - increased T wave amplitude and width; may also see ST elevation C. Marked ST elevation with hyperacute T wave changes (transmural injury) D. Pathologic Q waves, less ST elevation, terminal T wave inversion (necrosis) E. Pathologic Q waves, T wave inversion (necrosis and fibrosis) F. Pathologic Q waves, loss of R waves (fibrosis) STEMI Typical Progression 84
Acute Inferior MI Axis is shifting leftward Acute Inferior MI#1 ST elevation Qs Qs 45% of MIs Acute Anterior r MI IPa Page Same Patient~2 hrs later Acute Inferior MI #2 New ST elevation Worsened ST elevation Qs Qs 40% of MIs Acute ein Inferior rm MI IPa Page Same Patient 9 days later Acute Inferior MI #3 Permanent left axis deviation But NO anterior infarct (no Qs) Permanent Q waves (inferior wall scar) 1/3 of Inferior MIs Acute RVent Ventricle MI Page I
Acute Lt Lateral lm MI IPage Page Where is the Pathology? Acute Anterior MI 15% of MIs Acute epo Posterior MI IP Page 7 Acute Anterior MI (ST Elevation in V1 - V4) ST Elevation What is the R wave axis? 7 Practice: Infarct Location 93 Where is the Pathology? Acute Inferior MI 8 t
Acute Inferior MI Acute (ST Inferior elevation MI in II, III, F) 8 Where is the Pathology? 10 Where is the Pathology? 9 Acute Inferolateral MI Acute Inferior MI & Right Ventricle MI Acute Inferior & Right Ventricle MI 10 Acute Inferolateral Acute MI Inferolateral MI (ST elevation in II, III, F, V5, V6) Note the axis has not shifted yet, because it is early in the AMI, and there are no loss of R waves yet. Where is the MI? Large R waves ST Depression V1, V2, V3 Large R Waves Depressed STs Normal V1 V3 9 11
Acute Posterior MI Large R waves ST Depression V1, V2, V3 Large R Waves Depressed STs 11 Confounders Normal V1 V3 104 WPW Graphic Wolff-Parkinson-White synd. Wolff-Parkinson-White synd. Short PR Delta wave Widened QRS Short PR, Wide QRS, Delta wave Rapid Interpretation Tips Rapid Interpretation Tips Identify the rhythm. If supraventricular, Rule out left bundle branch block. 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, betablocker, clopidogrel, statin, etc. WPW False Q waves mimic MI False Q Waves (the Delta wave) 108
Other Confounders Benign Normal Variant ST Elevation Mild upsloping ST segments 110 10 Other Confounders Left Ventricular Hypertrophy Tall R waves V5, V6 strain Deep S waves V1, V2 Tall R waves in V5, V6; deep S waves in V1, V2 Pericarditis Depressed PR segments NO loss of R waves Elevated STs in multiple leads Depressed PR segments Elevated STs in multiple leads Other Confounders: Digoxin (ST Depression) Depressed ST segments
ST Depression (a diagnostic challenge) Can be caused by: Ischemia Digoxin effect Tachycardia LVH, BBB Hypokalemia NSTEMI (Non Q wave MI) 115 44 y.o. female with history of tachycardia 12 Ischemic ST Depression (a positive exercise ECG) WPW (short PR, Wide QRS, Delta waves) short PR false Q waves delta waves 12 Practice: Confounders 117 30 y.o. male with positional chest pain 120 13
Depressed PR segments LBBB 13 Pericarditis Elevated ST segments in multiple leads 121 Left Bundle Branch Block LAE LBBB 125 Putting it all together Where is the Pathology? Right Bundle Branch Block 1 2 6
127 128 Sinus Tach Acute Anteroseptal MI Anterior MI Elevated ST segments Acute Anterior MI Elevated ST segments Rhythm? Pathology? 6 MI? What rhythm is this? Anterior MI Acute Inferolateral MI Elevated STs II, III, avf, V5, V6
Rhythm? MI? Anterolateral Ischemia- Junctional Rhythm Acute Acute Inferolateral Inferolateral MI ECG MI 137 Anterolateral Ischemia- Junctional Rhythm Junctional Rhythm; Acute Anterolateral Ischemia P P Inverted Ts Rhythm? Pathology? 14 138 MI? Acute Inferolateral MI ECG 14 Ventricular aneurysm Large Old Anterolateral MI Large Qs V1 V6 Ventricular aneurysm
Case report: 58 y.o. male c/o chest tightness and shortness of breath x 20 minutes, which gradually subsided. Recurrent episodes over several months. Pt thought it was acid reflux, but finally goes to ED. Pt is noncompliant with statin therapy, & admits to poor diet. Family Hx cardiac disease. Hx HTN. Meds: Plavix, ACE inhibitor. EKG follows. What treatment? Excellent outcome: Pt is active, healthy, has improved diet, is compliant with meds; and has inspired thousands of Americans to go to their physician for cardiac evaluations The Bill Clinton Effect HIPPA note: this is not Bill Clinton s actual ECG! Angiography reveals 90% occlusion in some coronary arteries. But he did have CABG & became adherent to his meds Ischemia / Impending MI no loss of R waves yet but inverted T waves Treatment: quadruple CABG (coronary artery bypass graft).