1. EKG

2. Reading: Klabunde, Cardiovascular Physiology Concepts –Chapter 2 (Electrical Activity of the Heart) pages 27-37 Dubin, Rapid Interpretation of EKG’s, 6th Edition.

3. Check these hyperlinks out! http://www.themdsite.com/personal_reference.cfm Dubin’s EKG Pocket Guide

4. Basic Principles

5. The EKG records the electrical activity of contraction of the heart muscle Depolarization may be considered an advancing wave of positive charges within the heart’s myocytes

7. - - - - - - - - - - - + + + + + + + + + + – – + –

8. - - - - - - - - - - - + + + + + + + + + + + + + + + + - - - - - - - - - - - + + + + + + + + + + + + + + + + + + – – + – Depolarization Wave

9. Depolarization Repolarization

10. Conduction System

11. SA Node Anterior Internodal Pathway Middle Internodal Pathway Posterior Internodal Pathway Anterior interatrial myocardial band (Bachmann’s Bundle) Left Atrium AN Region N Region NH Region AV Node Bundle of His Right Bundle Branch Left Bundle Branch Anterior Division Posterior Division Right Atrial Tracts

12. Sinus Rhythm The SA (Sinus) Node is the heart’s dominant pacemaker. The ability of a focal area of the heart to generate pacemaking stimuli is known as Automaticity. The depolarization wave flows from the SA Node in all directions.

13. Atrio-Ventricular (AV) Valves Prevent blood backflow to the atria Electrically insulate the ventricles from the atria

14. AV Conduction AV node is situated on right side of interatrial septum near the ostium of the coronary sinus When the wave of depolarization enters the AV Node, depolarization slows, producing a brief pause, thus allowing time for the blood in the atria to enter the ventricles.

20. Repolarization Plateau Rapid Repolarization Phase ST Segment

23. Ventricular Systole QT Interval

24. Recording the EKG

25. Limb Leads –I –II –III –AVR –AVL –AVF Chest Leads –V 1 –V 2 –V 3 –V 4 –V 5 –V 6

33. Autonomic Nervous System

38. Check for these on every EKG RATE Rhythm Axis Hypertrophy Infarction

39. Sinus Rhythm The SA (Sinus) Node is the heart’s dominant pacemaker. The generation of pacemaking stimuli is automaticity. The depolarization wave flows from the SA Node in all directions.

40. Sinus Rhythm The Sinus Node is the heart’s normal pacemaker Normal Sinus Rhythm: 60-100/min. Sinus Bradycardia: Less than 60/min. Sinus Tachycardia: More than 100/min.

41. Automaticity Foci Level –Atria –AV Junction –Ventricles Inherent Rate Range –60-80/min. –40-60/min. –20-40/min.

42. Overdrive Suppression SA Node Atrial Foci (60- 80 bpm) Junctional Foci (40-60 bpm) Ventricular Foci (20-40 bpm) Overdrive Suppression

50. RATE Say “300, 150, 100” …“75, 60, 50” But for bradycardia: rate = cycles/6 sec. strip ✕ 10

51. Check for these on every EKG Rate RHYTHM Axis Hypertrophy Infarction

52. RHYTHM Identify the basic rhythm, then scan tracing for prematurity, pauses, irregularity, and abnormal waves. Check for: P before each QRS. Check for: QRS after each P. Check: PR intervals (for AV Blocks). Check: QRS interval (for Bundle Branch Block)

53. Sinus Rhythm Origin is the SA Node (“Sinus Node”) Normal sinus rate is 60 to 100/minute Rate more than 100/min. = Sinus Tachycardia Rate less than 60/min. = Sinus Bradycardia

55. Sinus Bradycardia

56. Sinus Tachycardia

57. Arrhythmias Irregular rhythms Escape Premature beats Tachy-arrhythmias

58. Irregular Rhythms Sinus Arrhythmia Wandering Pacemaker Multifocal Atrial Tachycardia Atrial Fibrillation

59. Sinus Arrhythmia Irregular rhythm that varies with respiration. All P waves are identical. Considered normal.

60. Wandering Pacemaker Irregular rhythm. P waves change shape as pacemaker location varies. Rate under 100/minute

62. Multifocal Atrial Tachycardia Irregular rhythm. P waves change shape as pacemaker location varies. Rate greater than 100/minute

64. Atrial Fibrillation Irregular ventricular rhythm. Erratic atrial spikes (no P waves) from multiple atrial automaticity foci. Atrial discharges may be difficult to see.

66. Escape Escape Rhythm –Atrial Escape Rhythm –Junctional Escape Rhythm –Ventricular Escape Rhythm Escape Beat –Atrial Escape Beat –Junctional Escape Beat –Ventricular Escape Beat

71. Premature Beats Premature Atrial Beat Premature Junctional Beat Premature Ventricular Contraction (PVC)

75. Atrial Bigeminy

79. PVC’s

81. Bigeminy

84. Tachyarrhythmias

85. Paroxysmal Atrial Tachycardia (Supraventricular Tachycardia) An irritable atrial focus discharging at 150- 250/min. produces a normal wave sequence, if P’ waves are visible.

86. P.A.T. with block (Supraventricular Tachycardia) Same as P.A.T. but only every second (or more) P’ wave produces a QRS.

87. Paroxysmal Junctional Tachycardia AV Junctional focus produces a rapid sequence of QRS-T cycles at 150-250/min. QRS may be slightly widened.

88. Paroxysmal Ventricular Tachycardia Ventricular focus produces a rapid (150-250/min) sequence of (PVC-like) wide ventricular complexes.

90. Atrial Flutter A continuous (“saw tooth”) rapid sequence of atrial complexes from a single rapid-firing atrial focus. Many flutter waves needed to produce a ventricular response.

92. Ventricular Flutter A rapid series of smooth sine waves from a single rapid- firing ventricular focus Usually in a short burst leading to Ventricular Fibrillation.

95. Atrial Fibrillation Multiple atrial foci rapidly discharging produce a jagged baseline of tiny spikes. Ventricular (QRS) response is irregular.

96. Ventricular Fibrillation Multiple ventricular foci rapidly discharging produce a totally erratic ventricular rhythm without identifiable waves. Needs immediate treatment.

97. Block Sinus Block AV Block Bundle Branch Block Hemiblock

98. Sinus (SA) Block An unhealthy Sinus (SA) Node misses one or more cycles (sinus pause) The Sinus Node usually resumes pacing However, the pause may evoke an “escape” response from an automaticity focus

100. 1 ° AV Block PR interval is prolonged to greater than 0.2 sec (one large square)

101. 1 ° AV Block

103. 2 ° AV Block (Some P waves without QRS Response) Wenkebach –PR gradually lengthens with each cycle until the last P wave in the series does not produce a QRS

104. 2 ° AV Block (Some P waves without QRS Response) Mobitz –Some P waves don’t produce a QRS response. –Intermittent may cause an occasional QRS to be dropped. –More advanced may produce a 3:1 pattern or higher AV ration.

105. 2 ° AV Block (Some P waves without QRS Response) 2:1 AV Block –May be Mobitz or Wenkebach.

107. 2 ° AV Block

109. 3 ° AV Block (“Complete” Block) P waves of SA node origin QRS’s if narrow, and if the ventricular rate is 40- 60/min., then origin is a junctional focus.

110. 3 ° AV Block (“Complete” Block) P waves of SA node origin QRS’s if PVC-like, and if the ventricular rate is 20-40/min., then origin is a ventricular focus.

111. 3 ° AV Block

112. Bundle Branch Block Find R, R ' in right or left chest leads Always check: Is QRS within 3 tiny squares?

114. Left Bundle Branch Block

116. Right Bundle Branch Block

117. Hemiblock Block of Anterior or Posterior Fasicle of the Left Bundle Branch Always check: Has Axis shifted outside normal range? Anterior Hemiblock: –Axis shifts leftward > L.A.D. Look for Q 1 S 3 Posterior Hemiblock: –Axis shifts rightward > R.A.D. Look for S 1 Q 3

118. Left Anterior Hemiblock

119. Check for these on every EKG Rate Rhythm AXIS Hypertrophy Infarction

120. Using Vectors to Represent Electrical Potentials A vector is an arrow that points in the direction of the electrical potential generated by current flow The arrowhead of the vector is in the positive direction The length of the arrow is drawn proportional to the voltage of the potential

121. N S EW

123. – – – – – – – – – – – – – – – – + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

124. RV LV

130. – – – – – – – – – – – – – – – – + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

131. Lead I –+

133. Axis QRS above or below baseline for Axis Quadrant (Normal vs. R or L Axis Dev.) –For Axis in degrees, find isoelectric QRS in a limb lead Axis rotation in the horizontal plane (chest leads) find “transitional” (isoelectric) QRS

138. Causes of Axis Deviation Change of the position of the heart in the chest Hypertrophy of one ventricle Myocardial infarction Bundle branch block

139. Check for these on every EKG Rate Rhythm Axis HYPERTROPHY Infarction

140. Hypertrophy P wave for Atrial hypertrophy R wave for Right Ventricular Hypertrophy S wave depth in V1 + R wave height in V5 for Left Ventricular Hypertrophy

141. Right Atrial Hypertrophy Large, diphasic P wave with tall initial component Seen in lead V 1

142. Left Atrial Hypertrophy Large, diphasic P wave with wide terminal component Seen in lead V 1

143. Right Ventricular Hypertrophy R > S wave in V1 –R wave gets progressively smaller from V1-V6 S wave persists in V5-V6 RAD with slightly widened QRS Rightward rotation in the horizontal plane

145. Left Ventricular Hypertrophy mm of S in V1 mm of R in V5 + Total: If more than 35 mm there is LVH

146. Left Ventricular Hypertrophy LAD with slightly widened QRS Leftward rotation in the horizontal plane Inverted T wave –Slants downward gradually, but up rapidly

147. Hypertrophy Left Ventricle and Left Atrium

148. Check for these on every EKG Rate Rhythm Axis Hypertrophy INFARCTION (and Ischemia)

149. Infarction Scan all leads for: –Q waves –Inverted T waves –ST segment elevation or depression –Find the location of the pathology and then identify the occluded coronary artery

150. Necrosis = Q wave (significant Q’s only) Significant Q wave: –One mm wide (0.04 sec in duration) or –1/3 the amplitude (or more) of the QRS Omit lead AVR when looking for significant Q’s Old infarcts: Q waves remain for a lifetime

151. Injury = ST elevation Signifies an acute process ST elevation associated with significant Q waves indicates an acute (or recent) infarct ST depression (persistent) may represent a “subendocardial infarction”

153. Ischemia = T wave inversion Inverted T wave (of ischemia) is symmetrical –Normally T wave is upright when QRS is upright, and vice versa Usually in the same leads that demonstrate signs of acute infarction (Q waves and ST elevation)

160. Inferior Infarction

161. Inferior Infarction (+ LBBB)

164. Anterior Infarction

166. Postero-Lateral Infarction

167. Miscellaneous

168. Digitalis EKG appearance with digitalis –Salvador Dali mustache –T waves depressed or inverted –QT interval shortened

169. Digitalis Digitalis Excess (Blocks) –SA Block –P.A.T. with Block –AV Blocks –AV Dissociation Digitalis Toxicity (Irritable foci firing rapidly) –Atrial Fibrillation –Junctional or Ventricular Tachycardia –Multiple PVS’s –Ventricular Fibrillation

170. Calcium

171. Decreased Potassium (Hypokalemia)

172. Hyperkalemia

173. Pulmonary Embolism S 1 Q 3 T 3 –Wide S in I, large Q and inverted T in III Acute Right Bundle Branch Block R.A.D. and clockwise rotation Inverted T waves in V1 – V4 ST depression in II

174. Pulmonary Embolism

175. Pacemakers

176. Wolf-Parkinson-White Syndrome

178. Review the 12-lead EKG on top in the next slide (EKG b). Anything unusual about it?

181. The End