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EKG 101 Deborah Goldstein Georgetown University Department of Internal Medicine.

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Presentation on theme: "EKG 101 Deborah Goldstein Georgetown University Department of Internal Medicine."— Presentation transcript:

1 EKG 101 Deborah Goldstein Georgetown University Department of Internal Medicine

2 Steps to Interpreting an EKG Rate Rhythm Axis Intervals (PR, QRS, QTc) Hypertrophy ST segments T waves Q waves

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4 Rate

5 Naming stuff

6 Normal Sinus Rhythm P before every QRS –Best places to look: II, V1 QRS after each P

7 Axis 1. The direction of the mean electrical vector, representing the average of current flow in the frontal plane. 2. Normal axis: –30 to +90 degrees.

8 Axis

9 Look at lead I and aVF. Then find the isoelectric lead (where the QRS complex is most nearly biphasic). Then go 90 degrees perpendicular to the isoelectric lead.

10 Axis

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12 Rate, Rhythm, Axis

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15 Ddx of Axis Deviation LAD Left ventricular hypertrophy, Left anterior fascicular block, LBBB, Inferior wall MI Pregnant, ascites, short/fat RAD Right ventricular hypertrophy, Left posterior fascicular block, RBBB, lateral wall MI PE

16 PR Interval Normal PR = 0.12 – 0.20 seconds (3-5 little boxes) Long PR >0.20 seconds (>5 little boxes) =Delayed conduction from atria to ventricles First-degree AV block –PR>0.20 seconds –NO dropped QRS

17 Second Degree AV Block Wenckebach (Type 1) =block within AV node –PR interval progressively lengthens...then dropped QRS Mobitz (Type 2) =block within His-Purkinje system –Fixed PR with dropped QRS –WORSE! –Sarcoid, Lyme.... –Pacemaker!

18 Third Degree AV Block =Failure of conduction of any atrial impulses to get to the ventricles =Complete AV block Causes of Acute AV Block: Calcium channel blockers Acute RCA occlusion Digoxin toxicity

19 What kind of AV Block?

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23 QRS Interval Normal = seconds Wide QRS = >0.12 seconds (>3 little boxes) PVC...if >3 in a row or >6/min=VTach RBBB, LBBB Left fascicular hemiblock Hyperkalemia Narrow QRS= <0.06 sec SVT ( bpm) Idiojunctional rhythm (40-60 bpm) Premature junctional complex

24 Chest Leads V1 V6

25 Bundle Branch Block V1-V2 = Right precordial leads V5-V6 = Left precordial leads LBBB Rabbit ears in V6 represent delay between depolarization from the septum  to the LV RBBB Rabbit ears in V1 represent delay between depolarization from the septum  to the RV

26 Normal: V1: rS complex V6: qR complex RBBB: V1: Rabbit Ears (rSR) V6: qRS complex LBBB: V1: wide QS complex V6: Rabbit Ears V1 V6

27 Wide QRS—Why?

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29 QT Interval Should be < ½ (R-R’ interval) Measure from the start of the QRS to end of T wave Varies with heart rate, so correct for RR interval Normal QTc: women=0.44, men=0.42 QTc = QT (#of small squares) x 0.04 √RR Long QT can lead to ‘R on T’  Death

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31 Causes of Long QT **Think ‘Lytes and Meds first! Low K, Low Ca, Low Mg Macrolides, Quinolones All Antipsychotics (Haldol worst, Geodon least) SSRIs Sotalol, Quinidine, Ondansetron, Amio, TCAs Pts w/LVH or CHF are predisposed to medication- related lengthening of QT interval! –Avoid Macrolides, Quinolones in them!

32 Long QT: Less common causes Hypothyroid Hypothermia AV Block MI CVA Head injury Congenital long QT

33 Atrial Enlargement RAE P wave is tall and peaked (>2.5mm high) OR Biphasic P wave with initial positive inflection Ddx: Pulmonary HTN, COPD, PE LAE P wave is wide (>0.12 sec) and notched in the middle “M” OR Biphasic P wave with terminal negative inflection Ddx: Systemic HTN, Aortic Insufficiency, Mitral Stenosis

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35 Which Atria is Enlarged?

36 IIV1

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38 LVH Criteria Sokolow + Lyon –S V1+ R V5 or V6 > 35 mm Cornell criteria (Circulation, 1987;3: ) –S V3 + R avl > 28 mm in men –S V3 + R avl > 20 mm in women Framingham criteria (Circulation,1990; 81: ) –R avl > 11mm, R V4-6 > 25mm –S V1-3 > 25 mm, S V1 or V2 + –R V5 or V6 > 35 mm, R I + S III > 25 mm Romhilt + Estes (Am Heart J, 1986:75:752-58) –Point score system (Am Heart J, 1999;37:161)

39 LVH “S V1+ R V5 or V6 > 35mm”

40 ST changes: axis + anatomy Lateral: –I, aVL –LCA, CFX Anterior: –V1, V2, V3, V4 –LAD Inferior: -II, III and aVF -RCA (or LCA) Memorize this slide

41 Q waves Normal Q wave: –Small septal Qs in I, aVL, V5, V6 –Isolated Qs in III, V1 Pathologic Q wave: –wider than 1 small box (0.04 sec) –OR >25% height of the R wave in that complex

42 Normal Q waves

43 Abnormal Q Waves

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45 Non-ST Elevation MI =Severe subendocardial ischemia Marked, diffuse ST depressions in I, II, III, aVL, aVF, V2-V6

46 2 EKGs, several hours apart

47 Acute ST Elevation MI 1.Normal 2.Hyperacute T wave Elevation 3.Acute ST Elevation 4.Hours Later ST Elev, Q begins to form, T wave inverts 5.Days Later Q wave, T wave inversion 6.Weeks Later Q wave

48 A 55 year old man with 4 hours of "crushing" chest pain.

49 Acute Inferior Wall MI ST elev in II, III, AVF Reciprocal ST depression in anterior leads (V2-V4) =RCA occlusion (some LCx)

50 A 53 year old man with Ischemic Heart disease

51 Old Inferior Wall MI Pathologic Q wave in II, III, AVF: –wider than 1 small box (0.04 sec) –OR >25% height of the R wave in that complex

52 An 83 year old man with aortic stenosis.

53 LVH, LAE Romhilt-Estes LVH Point System: 3 points for Left Atrial Enlargement –M shaped P wave in II –P has prominent terminal negative component in V1 3 points for: –R wave in V5 or V6 >30mm –or S wave in V1 or V2 >30mm –or R or S in limb leads>20mm >5 points: definite LVH

54 A 76 year old man with breathlessness.

55 Afib with RVR Irregularly irregular ventricular rhythm. Must look carefully to see it is NOT regular

56 A 72 year old man on routine office visit

57 Ventricular Pacemaker Pacer spikes—hard to see! Wide QRS complexes Pacemaker starts after a long R - R interval following a blocked atrial premature beat...then NSR

58 A 58 year old man on hemodialysis presents with profound weakness after a weekend fishing trip.

59 Hyperkalemia K >8.0 Wide, tall and tented T waves Wide QRS Small or absent P waves Atrial fibrillation Shortened or absent ST segment Ventricular fibrillation

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61 Atrial Flutter Saw tooth baseline with rate of Causes: –Ischemic heart disease –Hypertension –Mitral valve disease –Thyrotoxicosis –Cardiomyopathy

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63 Pericarditis Evolves over hours-weeks 1.PR depression, ST elevation (concave up) in same leads, upright T 2.Normal P, normal ST, flat T 3.Normal P, normal ST, T Wave inversion 4.normal P, normal ST, upright T

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65 Hypocalcemia Long QT Inverted T waves

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