                       EKG READING PEARLS

READING SCHEME:
     1.  Rate
     2.  Rhythm
     3.  Axis
     4.  Hypertrophy & Blocks
     5.  Ischemia, Injury, Myocardial Infarction
     6.  Miscellaneous Effects

RATE:
1.  Number Cycles in 6 secs x 10 = rate

2. Bold Dark Line:
     300   150    100    75    50
          NOTE: If rate < 50 use 6 sec method

RHYTHM
     Sinus in Origin
     Superventricular dysrhythmia
     Junctional Beats & Rhythms
     Ventricular Dysrhythmia
     A-V Irregularities & Blocks

AXIS:
     Look at 1st 0.4 sec of QRS complex in Leads I and AVF
     AXIS DEVIATION Lead 1    Lead AVF       VALUES                 Normal (None)         + (up)                 +      0  - + 90
             RAD              -(down)               +                 +90  - +180
         Extreme RAD                  -                      -                -90 - -180
              LAD                 +                      -                    0 - -90






HYPERTROPHY & BLOCKS
Atrial Hypertrophy:
1. Right Atrial Hypertrophy (p-pulmonale)
     Tall narrow P waves (< 2.5mm) in Leads II (most sensitive), III, AVF
     Width of P wave not increased
      2 mm upright (first part) of P wave in V1 or V2

2.  Left Atrial Hypertrophy (p-mitrale)
     P waves are wide (> 3mm (0.12sec) and notched in 1 or more limb leads
     P waves of V1 and V2 may have negative terminal component with depth &
          width  1mm

3. Biatrial Hypertrophy
     Criteria for both RAH and LAH is met

Ventricular Hypertrophy
1. Right Ventricular Hypertrophy (RVH)
     RAD
     R wave > S wave in V1 (R:S > 1)
     R wave in V1 + S wave in V6  11mm
     Deep S waves in V5 & V 6, I, AVL
     RR' may be present in V1
     2o T wave changes in V1 - 3 = RV Strain Pattern
          S-T depression with upward convexity in leads with + QRS
          Asymmetric T-wave inversion

2. Left Ventricular Hypertrophy
     Estes Romhilt Point Score System
     1.   R or S in V1  15 mm 
          S in V1 - 3  25 mm                4 pts
          R in V4 - 6  25 mm
          R in I + S in III  15 mm
          R in V5 or V6 + S in V1  35mm 
          R in II, III or AVF 20 mm
          R in AVL  13 mm
     2.   Any ST shift (without digitalis)             3 pts
          Typical St-T strain (with digitalis)         1 pt
     3. LAD -15o or more                     2 pts
     4. QRS interval 0.09 sec or more             1 pt

Score: 5 or more = LVH   3 - 4 = probable LVH


3. Biventricular Hypertrophy
     LVH per chest leads (voltage criteria) + RAD per limb leads
     LVH per chest leads + prominent R waves in Right Chest Leads
     Shallow S wave in V1 + strikingly deeper S in V2
     RVH per chest Leads + LAD per limb leads

Fascicular Blocks:
1. Left Bundle Branch Block (LBBB)
     QRS > 0.12 sec
     Broad QS or rS in V1 - 3
     RR' in I, AVL, V4 - 6
     NOTE: CAN'T Diagnose Q wave or Voltage MI if LBBB present
2. Right Bundle Branch Block (RBBB)
     QRS > 0.12 sec
     Deep and slurred S in I, AVL, V4 - 6
     rR' in V1 - 3
     NOTE: Remember to look for Hemiblocks if RBBB present
3. Left Anterior Hemiblock
     LAD, Axis = -45 to -90
     Normal QRS duration unless RBBB also present
     Small q I and small r in III
     No other factors for LVH
4. Left Posterior Hemiblock
     RAD; Axis +105 - +180
     Normal QRS duration unless RBBB also present
     Small r in I and small q in III

Ischemia, Injury, MI
Ischemia:
     Symmetric T wave inversion
     ST segment depression
     U wave inversion
     Tall peaked "hyperacute" T waves
Injury:
     ST segment elevation > 1mm above baseline
     T wave inversion
Myocardial Infarction:
     Significant Q waves (>1mm wide or > 25% of R wave height)
     Reciprocal Changes - occur in leads opposite from area of infarction
          Less magnitude than changes that occur in leads of 1o involvement


Localization of MI 
     Anteroseptal        Q or QS in V1 - 3
     Anterior            Q or QS in V2 - 4
     Anterolateral       Q or QS in I, AVL & V4 - 6
     High Lateral        Q or QS in I & AVL
     Extensive Anterior  Q or QS in I, AVL, V1 - 6
     Inferior (Diaphragmatic) Q or QS in II, III, AVF
     Posterior           Significantly Tall R waves in V1 - 3

MISCELLANEOUS EFFECTS
Drug Effects:
1. Quinidine
     Prolonged QT interval is the hallmark
     U wave
     ST segment depression
     W T wave
     Wide notched P wave
Note: Other drugs that can prolong QT interval
     Procainamide, Disopyramide, Phenothiazine, Tricyclic
2. Digitalis
     ST depression with a U shaped configuration
     T wave flattening & Inversion
     Prolongation of P-R interval
     Shortening of Q-T interval 
** Toxicity = Development of dysrhythmia
     Classic = PAT, Double or Triple AV junctional, Bidirectional V-Tach
     Common = PVC's, Ventricular Bigeminy, Nonparoxysmal junction
          tachycardia
3. Digitalis & Quinidine Combined = Closely resembles Hypokalemia 

Electrolyte Abnormalities
1. Potassium
     Hypokalemia = Flattening of T wave & development of prominent U wave
     Hyperkalemia = T wave tenting, Prolonged P-R interval, Shortening of Q-T
          interval, Decreased P wave height (may disappear)
2. Calcium
     Hypocalcemia = Prolongation of Q-T interval 
          ** Corrected QT = Q-T measured / RR interval
         T waves usually normal but can become inverted if severe hypocalcemia  Hypercalcemia = Shortened Q-T interval



Other Conditions:
1. Pericarditis
     ST elevation with a flat or upward concavity
     No significant Q waves
2. Hypothermia
     Sinus Bradycardia
     Prolongation of all intervals
     Atrial Fibrillation or Flutter
     J wave =pointed elevation of the initial portion of the ST segment @ J point
3. Ventricular Aneurysm
     Persistent Current of Injury Pattern (Persistent St elevation)
4. Pulmonary Embolism (Not specific use in conjunction with other observations)
     Sinus Tachycardia
     RAD
     RAH
     Inverted T waves in V1 - 3
     Pseudo-Diaphragmatic MI pattern
          Q wave, ST elevation, & T wave inversion in III only
          Deeps S Wave in II
          Absent Q wave in AVF
     S1,Q3,T3 inverted Pattern
     S1, S2, S3 = prominent S waves in V1 - 3
     Prominent S waves in V5 & V6
     Transient RBBB at onset
5. Wolfe-Parkinson White- Syndrome
     Delta Wave
     Short P-R interval (<0.12)
     Prolonged QRS (> 0.10)
6. Lown-Ganong-Levine Syndrome
     Short P-R interval in all leads
     No Delta Waves
     Intermittent supraventricular tachycardia
7. Subarachnoid Hemorrhage/ CVA
     Deeply inverted, wide T waves with diffuse distribution
     Non-specific ST-T changes
     Prolonged QT interval
     Prominent U wave
     Supraventricular Tachycardia





                       RHYTHM VARIATIONS
     
NSR Criteria:
     1. P waves of sinus origin (P axis 0 - +90)
     2. Constant P wave configuration in a given lead
     3. Constant and normal P-R interval (0.12 - 0.20 sec)
     4.  Rate between 60 and 100 beats per min
     5.  Constant P-P Interval
     6.  Every P has a QRS and every QRS has a P

SUPERVENTRICULAR DYSRHYTHMIA
1. Sinus Tachycardia
     Heart Rate > 100
     Normal P wave, QRS complex & T wave
     PR interval maybe slightly shortened

2. Sinus Bradycardia
     Heart Rate < 60
     Normal P wave, QRS complex & T wave

3. Sinus Arrhythmia
     Sinus Rhythm
     Normal P wave, QRS interval, & T wave
     Cyclic Variation in heart rate, usually associated with respiration

4. SA Block
     Dropped P waves (non conducted; QRS missing too)
     SA Wenckebach: Shortening of PP interval leading to dropped P wave
     Type II: Absent P wave seen as an exact multiple of the other sinus cycles
     ** Returns in Phase 

5. Sinus Arrest
     Absence of P waves & QRS complex
     Returns out of phase     
          Presence of escape beats after initial pause

6. PAC (Premature Atrial Complexes)
     Premature ectopic P wave
          P' wave appears different from normal P waves
     Incomplete compensatory pause
     Normal QRS


7.  Atrial Tachycardia (run of 6 or more PAC)
     Atrial rate of 160 - 240 beats/min
     First beat is early
     Ectopic P waves look the same as each other but differ in appearance from
          sinus P waves
     Regular constant P-R interval
     Normal QRS
    *** Paroxysmal Atrial Tachycardia - A Tach with sudden onset & abrupt ending

8.  Multifocal Atrial Tachycardia (run of 6 or more PAC from different atrial foci)
     Atrial rate of 100 - 200 beats/min
     First beat is early
     Ectopic P waves differ in appearance from each other ( 3 or more ectopic
          foci) & differ in appearance from sinus P waves
     irregular r P-P interval
     Irregular P-R interval
     Nonconducted ectopic P waves may occur
     Normal QRS

9. Atrial Flutter
 **Type I = Atrial Rate 220 - 350
 **Type II = Atrial rate 340 - 430 (intermediate between flutter I fibrillation)
     Atrial Rate > 220
     F waves replace P waves (negative component of sawtooth pattern)
     Sawtooth appearance in leads II, III, AVF
     Positive Peaks in V1
     P-R interval not measurable
     2:1; 3:1; 4:1 conduction (not all P waves conduct to ventricles)

10. Atrial Fibrillation
     Irregular irregular rhythm
     Atrial rate > 400
     Multifocal f waves replace P waves best seen in V1
     Irregular ventricular response
     No measurable P-R interval

11. Wandering Atrial Pacemaker
     P waves vary according to pacemaker sir; Maybe inverted or upright
     Changing P-R & R-R interval
     Irregular Rhythm



JUNCTIONAL BEATS & RHYTHMS
1. Premature Junctional Complexes
     Ectopic beat is premature
     Inverted P wave preceding or following QRS
     Distorted T if P follows QRS
     If P-R interval is present will be < 0.12 sec
     Usually Normal QRS

2. Junctional Escape Beat
     Ectopic Beat occurs late in cycle
     Can be preceded by a P wave which is inverted or sinus but P-R interval
short
     P waves usually inverted in I, II, III and upright in AVR

3. Junctional Escape Rhythm
     Run of 6 or more JEB
     Rate 40 - 60

4. Accelerated Junctional Rhythm
     Accelerated = Rate 60 - 100
     Junctional Tachycardia = Rate 100 - 160
     Accelerated Junctional Tachycardia = Rate > 160

5. Paroxysmal Junctional Tachycardia
     Abrupt onset & Termination
     Rate 140 - 200
     Normal QRS
     
6. A-V Nodal Reentry Tachycardia
     Narrow QRS
     Aberrancy uncommon
     P' Wave maybe buried in QRS
     May see r' or R' in V1
     Negative P' wave in leads II, III, AVF
     Long initiating P'R interval









VENTRICULAR DYSRHYTHMIA

1. Premature Ventricular Complexes (PVC) 
     P wave usually lost (unless retrograde conduction- inverted P after PVC)
     Widened & Bizarre QRS
     T Waves opposite in direction to QRS complexes
     Obscured S-T segments
     No measurable P-R interval    

Types OF PVCs  
     Uniform - all PVCs from same focus & are identical
     Multifocal - Different foci & QRS complexes have different appearance
     Interpolated - Located between 2 normal sinus beats without compensatory
          pause
     Malignant - R on T - quickly degenerates into V-Fib
     Couplets- 2 identical PVCs that occur back to back
     Bigeminy - repeating pattern of 1 normal beat followed by PVC
     Trigeminy - PVC after 2 normal beats or normal beat followed by 2 PVCs
Pauses:
     Full Compensatory - interval between QRS preceding PVC and one
          following PVCs is 2x that of normal cycle
     Partial Compensatory Pause - Interval is < 2x normal cycle
Lown's Grading System Of Ventricular Ectopy (predict death after MI)
     Grade               Type of PVC 
         O                    None
         1                    Occasional, isolated (30/hr)
         1a                   < 1/min
         1b                   > 1/min but <30 / hr total
         2                    > 30/hr
         3                    Multiform
         4a                   Two Consecutive
         4b                   3 or more consecutive
         5                    R on T

2. Ventricular Tachycardia
     Run of 3 or more PVCs
     1 st beat is early
     Rate 100 - 220
     No ectopic P waves
     No measurable P-R interval
     Wide, bizarre QRS (>0.12sec)
     LAD in 75 - 80% of patients
     Slightly irregular rate
3. Ventricular Fibrillation
     No identifiable wave forms
     Indeterminable rate
     Irregular
     Maybe coarse or fine
 
4. Torsades de Pointe 
     Combination of V-Tach & F-Fib
     Alternating positive & negative polarity of beats

5. Ventricular Flutter
     No recognizable atria activity
     Wide QRS
     Sine Wave appearance

6. Idioventricular Escape Rhythm (Ventricular Escape Rhythm)
     First beat is late
     no ectopic P waves
     Wide bizarre QRS
     Rate < 40

7. Accelerated Idioventricular Rhythm
     Ventricular rate slower than V-Tach
     Wide bizarre QRS
     Short Duration; seconds to minutes
     No ectopic P waves
     T wave usually opposite in direction from QRS

ATRIO-VENTRICULAR IRREGULARITIES AND BLOCKS

1. Atrioventricular Dissociation
     Atria & ventricles beat regularly but independently of each other
     Regular P-P intervals
     Regular R-R intervals
     No relationship between P-P & R-R intervals
     No relationship between P & QRS complexes

2. First Degree AV Heart Block
     Fixed prolonged P-R interval > 0.20 in adults & > 0.18 in kids
     Constant P-R interval
     Regular rhythm
     Normal P waves
     Normal QRS
3. 2nd Degree Heart Block
     Wenckebach (Mobitz Type I) 
          Progressive lengthening of P-R interval until QRS is dropped
          Shortening of R-R interval
          Normal P Waves & QRS Complexes
      Infranodal Block (Mobitz Type II)
          Constant P-R in conducted beats
          Widened QRS due to conduction delay
          Occasional dropped QRS-T complex
          Constant R-R intervals in conducted beats
          P-P interval containing non-conducted P waves equal to 2 normal P-P intervals

4. 3rd Degree Heart Block (Complete Heart Block)
     Independent atrial & ventricular pacing
     P-P intervals regular
     R-R intervals regular
     No relationship between P-P & R-R intervals
     Ventricular rate usually < 45
