9. Appearance of waves
• Positive deflection [upward]
• If electrical impulses flowing towards
that lead
• Negative deflection [downward]
• If electrical impulses flowing away from
that lead
27. QRS AXIS
• Indicator of overall direction that wave
of depolarization takes when passing
through ventricles
• Also called ANGLE
• Measured
• in degrees
31. • Right axis deviation [RAD]
• Beyond +90°
• Left Axis Deviation [LAD]
• Beyond -30°
32.
33.
34. Method 1
• Most precise method
• Use of vectors
• Measure overall height of QRS in lead I
& aVF
• Plot in graph paper
• Measure the ANGLE of vector
35.
36.
37.
38. Method 2
• Quick method
• Identify limb lead in which QRS complex
is isoelectric
• [with equal positive & negative
deflection]
• Implies: electric flow is at Right angle to
this lead
39.
40. Method 3
• For quick assessment
• Look at QRS complexes in lead I & II
43. Lead I Lead II Cardiac Axis
QRS Positive QRS Positive Normal Axis
QRS Positive QRS Negative Left Axis
Deviation
QRS Negative QRS Positive Right Axis
Deviation
44. • LAD
• WPW syndrome
• LBBB
• Inferior wall MI
• RAD
• RVH
• WPW syndrome
• Anterolateral MI
• Dextrocardia
45. P wave
• Present or not?
• Sinus rhythm
• If completely absent
•Atrial Fibrillation
•Hyperkalemia
• If intermittently absent
•Sinus arrest
52. • Width of P waves
• >2mm width: abnormal
• Bifid P wave
• Indicates Left Atrial enlargement
• P Mitrale
53.
54.
55. PR Interval
• From start of P wave to start of R wave
• Normally
• Not <3 small squares
• Not > 5 small squares
• Consistent
56. Short PR Interval
• AV junctional rhythm
• WPW syndrome
• Lown –Ganong-Levine syndrome
57. Long PR Interval
• Denotes delay in conduction through AV
node
• First Degree Block
• PR prolonged, constant
58.
59. Second degree Block
• Mobitz Type I
• PR progressively increase until one P
wave fails to produce QRS complex
60.
61. • Mobitz Type II
• PR interval normal & fixed,
• But occasional P waves fail to produce
QRS
62.
63. • Third Degree Block [Complete AV Block]
• No relationship between P waves & QRS
complex
64. • 2:1 Block
• Alternate P waves are not followed by
QRS complex
65. Q WAVE
• First negative deflection in QRS complex
• ? Pathological Q waves
• If
• >2 small squares deep
• >1 small square wide
• >25% of height of the following R wave
in depth
70. Progression of R wave
• V1: small R wave , large S wave,
• Gradually R wave increases, S wave
decreases
• V6: small Q wave, large R wave
• V3 and V4 : located midway between V1
and V6, QRS complex nearly isoelectric
in one of these leads
78. RBBB
• Right Bundle Branch Block
• Broad QRS complex
• Small r wave in V1, small Q wave in V6
• S wave in V1, R wave in V6
• R‟ wave in V1, S wave in V6
79.
80.
81. LBBB
• Left Bundle Branch Block
• Broad QRS
• Small Q wave in V1, Small r wave in V6
• R wave in V1, S wave in V6
• S wave in V1, R‟ wave in V6
82.
83.
84. • “WILLIAM MORROW”
• William: „W‟ in V1 & „M‟ in V6: LBBB
• Morrow: „M‟ in V1 & „W‟ in V6: RBBB
