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NEHI/CMC Cardiology > ECG > Flashcards

ECG Flashcards

1
Q

Steps for 12-lead ECG evaluation

A
  1. Axis 2. ST elevation, ST depression, inverted T’s 3. P wave characteristics 4. QRS complex, evidence of blocks, R wave progression 5. Ventricular hypertrophy? 6. QT interval
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2
Q

Causes of Right Axis Deviation

A

RVH, Lateral wall MI, COPD, pulmonary embolus

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3
Q

Causes of Left Axis Deviation

A

LVH, L anterior hemiblock, LBBB

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4
Q

What is the physiologic reasoning for the pathologic causes of right axis deviation?

A

Acute or chronic cor pulmonale/ increased pulmonary venous pressures/vasoconstriction

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5
Q

What is classified as ECG evidence of ischemia?

A

T wave inversion, ST depression >1mm

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6
Q

What is classified as ECG evidence of injury?

A

ST segment elevation >1mm

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7
Q

What is considered ECG evidence of Q Wave MI infarction?

A

ST elevation >1mm, T wave inversion, Q wave >25% of the R wave and >/= 0.4s

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8
Q

What is considered ECG evidence of a non-Q-wave MI?

A

T wave inversion, ST depression >1mm

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9
Q

What leads will show ECG changes in an anterior MI?

A

V1-6, mostly V3-5

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10
Q

What leads show wave changes in an inferior MI?

A

II, III, aVF

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11
Q

What leads show wave changes in a lateral MI?

A

I, aVL, V5, V6

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12
Q

What leads show wave changes in a posterior MI?

A

V7-9, V1, V2 show tall broad initial R wave, ST segment depression, and tall upright T waves

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13
Q

What leads show wave changes in an inferior posterior MI?

A

II, III, aVF, V6

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14
Q

What leads show wave changes in an anteroseptal MI?

A

V1-4

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15
Q

What leads show wave changes in an antero-posterior lateral MI?

A

V1-5, I aVL, V6

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16
Q

Which leads show wave changes in a right ventricular MI?

A

ST elevation in V4R

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17
Q

Which leads show wave changes in an anterolateral MI?

A

I, aVL, V4-6

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18
Q

What is the criteria for diagnosis of MI in the setting of a LBBB or v-pacing?

A

Sgarbossa’s Criteria: ST segment elevation >/= 1mm in the same direction of primary QRS deflection, ST segment depression >/= 1mm in V2 & 3 (V1 also?), ST segment elevation >/= 5mm in the opposite direction of primary QRS deflection *suggested S wave mod: ST elevation greater than 1/4 depth of the S wave

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19
Q

ECG criteria for Right Atrial Hypertrophy

A

Peaked in II, III, aVF (>2.5mm tall); biphasic V1 and V2 with upright > terminal

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20
Q

ECG criteria for Left Atrial Hypertrophyyes

A

Wide in the limb leads (>/= 0.11mm); notched in II, III, and V4-6; biphasic V1 with terminal portion >1mmWhere should V1 be placed?

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21
Q

What are the criteria for a left anterior fasicular block?

A

Left axis deviation >/= 30 degrees, qR in leads I and aVL, rS in leads II, III, and aVF

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22
Q

ECG criteria for a left posterior fasicular block?

A

right axis deviation >120 degrees, rS in leads I and aVL, qR in leads II, III, aVF

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23
Q

LBBB criteria

A

QRS >.1, notched/slurred R and no Q wave in lead I, notched/slurred R and no Q wave in aVL, rS or QS in V1, notched/slurred R and no Q in V6

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24
Q

RBBB criteria

A

QRS >.1, tall R/slurred S in lead I, wide slurred S in aVL, rSR or Rabbit ears/wide notched R in V1, wide slurred S in V5, tall R/slurred S in V6

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25
Q

RVH criteria

A

Poor R wave progression with right axis deviation, R>S/T wave inversion in V1, R

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26
Q

LVH criteria

A

left axis deviation, V6 R + V1 S = 35mm, S>R V1-2, Tall R/R>S in V5-6

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27
Q

What ECG changes are evidence of right ventricular strain?

A

ST depression and T wave inversion in leads III, aVF, V1-2

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28
Q

What ECG changes are evidence of left ventricular strain?

A

ST depression and T wave inversions in I, aVL, V5-6

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29
Q

What is the best way to calculate the QT interval?

A
  1. Find the lead with the longest QT interval (usually V2-3) 2. Find and measure the length of the longest R-R interval in that lead (in seconds) 3. Measure the QT interval after the longest R-R (in seconds) 4. If HR <60 use this QT measurement 5. If HR >60 use the square root of the R-R interval
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30
Q

What type of cells primarily compose the SA node?

A

P cells

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31
Q

At what rate does the SA node generate impulses?

A

60-100 bmp

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32
Q

By which arteries is the SA node perfused?

A

55-60% RCA, remaining population perfused by a branch of the circumflex artery

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33
Q

Type of cells which comprise the AV node

A

T cells/Transitional cells

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34
Q

What is the purpose of the AV node?

A

To slow down impulses on the way to the ventricles (see PR segment), allows for complete atrial contraction prior to ventricular stimulation, leading to 15-20% greater volume/cardiac output

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35
Q

Coronary artery which supplies the AV node in 85-90% of people

A

RCA

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36
Q

Which bundle branch divides into an anterior/superior/thin and posterior/inferior/broad fascicle?

A

left

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37
Q

Coronary artery which supplies the anterior fascicle

A

LAD

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38
Q

Coronary arteries which supply the posterior fascicle

A

RCA and circumflex artery

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39
Q

Coronary arteries which perfuse the bundle of his

A

LAD and posterior descending coronary artery

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40
Q

Type of cells that make up the his bundle, bundle branches, and purkinje fibers

A

Purkinje cells

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41
Q

True or false: there are also nodal cells present in the ventricles

A

True, this is how ventricular rhythms occur when other pacemakers fail (usually results in a rate <40)

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42
Q

What is unique about the automaticity of cardiac cells?

A

Any cell in the heart can exhibit it and generate a rhythm or dysrhythmia under the right circumstances

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43
Q

What kind of permeability does the sarcolemma exhibit?

A

Selective, via channels and gates

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44
Q

Name of the junctions which connect cardiac cells

A

Intercalated discs

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45
Q

Resting voltage of a cardiac cell

A

-60mV, primarily negative inside cell

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46
Q

What happens to a cell during depolarization?

A

Charge swaps from negative to positive inside

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47
Q

What four qualities do all cardiac muscle cells possess?

A

Automaticity, excitability, conductivity, contractility

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48
Q

What allows the sinus node to be the pacemaker and have the fastest rate of automaticity?

A

The high number of nodal cells which comprise it

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49
Q

What are the secondary or lateral pacemakers?

A

His bundle, junctional cells, ventricular purkinje cells

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50
Q

How does a cell depolarize?

A

Increased slow influx of sodium or calcium with decreased efflux of potassium until the membrane reaches its threshold of approximately -40mV (Phase 4) initiating an action potential

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51
Q

What do voltage do slow response cells reach as a result of threshold being reached and an action potential being initiated, disseminating an electrical impulse to other muscle cells?

A

0 mV (Phase 0)

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52
Q

What is phase 0 followed by in a pacemaker cell?

A

Phase 3 (Phases 1 & 2 do not exist): rapid depolarization caused by rapid efflux of potassium

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53
Q

Which cells are slow response cells?

A

Pacemaker cells

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54
Q

What are fast response cells?

A

All other cells

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55
Q

When purkinje cells (fast response cells) are at rest what is the membrane permeability like?

A

Permeable to potassium, relatively impermeable to sodium; allows for concentration gradient based potassium efflux causing relative intracellular negativity and extracellular positivity (approx a 90mV difference)

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56
Q

What is Phase 0 in fast response cells?

A

Rapid depolarization: impulse generated by pacemaker cells causes a sudden increase in sodium permeability in excitable myocardial and purkinje cells, causing sodium influx and cells to reach threshold at approximately -60 mV, opening fast sodium channels causing intracellular depolarization to 20 mV

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57
Q

What is phase 1 in fast response cells?

A

Channels for quick sodium influx close (H gates), a small efflux of potassium and a small influx of chloride occurs, causing decreased intracellular positivity until it is equal with the extracellular environment (~0 mV)

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58
Q

What occurs in phase 2 of fast response cells?

A

Plateau phase(>100ms): slow calcium channels allow calcium in with some sodium, potassium exits cell allowing the maintenance of 0 mV membrane potential, calcium influx occurs triggering muscle contraction (excitation contraction coupling)

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59
Q

Where on an ECG are phases 1 and 2 represented?

A

ST segment

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60
Q

What is phase 3 in fast response cells?

A

Rapid repolarization: potassium efflux combined with channel inactivation returns cells to relative negativity

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61
Q

What part of the ECG represents rapid repolarization?

A

T wave

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62
Q

What occurs during phase 4 in fast response cells?

A

Activation of the sodium potassium pump to actively remove sodium and bring in potassium at a ratio of 3:2 returning the cell to its resting membrane potential, remaining stable at -90 mV until the next impulse is generated

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63
Q

In which direction does the heart depolarize?

A

From endocardium to epicardium

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64
Q

What does the P wave represent?

A

Atrial depolarization

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65
Q

How do the ventricles depolarize?

A

Beginning at the septum from left to right, down to the apex, and ending at the basal portion of each ventricle and septum

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66
Q

What does the QRS represent?

A

Ventricular depolarization

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67
Q

In which direction does the myocardium repolarize?

A

Epicardium to endocardium with all areas of the ventricles recovering simultaneously

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68
Q

What on an ECG represents ventricular repolarization?

A

ST segment and T wave

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69
Q

Why is there no visual representation of atrial repolarization on an ECG?

A

It is obscured by the QRS complex

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70
Q

What is a refractory period?

A

Recovery period where myocardial cells are unable to be electrically stimulated (from phase 0 - phase 3, or QRS to the top of the T wave)

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71
Q

At what point in the electrical cycle is the cell able to be depolarized again?

A

Phase 3/halfway down the downslope of the T wave

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72
Q

What is the isoelectric line on an ECG?

A

Represents no current flow in the heart

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73
Q

What is seen on an ECG if electrical current flow is parallel to the lead axis with the current moving toward the positive pole?

A

Monophasic positive deflection

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74
Q

If the electrical current is parallel to the lead axis but the current is moving toward the negative pole what will the visual result on an ECG?

A

Monophasic negative deflection

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75
Q

If the electrical current is moving perpendicularly to the lead axis and moving toward neither the positive or negative pole what is the visual result on an ECG?

A

Biphasic deflection

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76
Q

Which leads result in larger deflection amplitude?

A

Parallel leads > perpendicular leads

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77
Q

What are two conditions that can affect the magnitude of electrical current?

A

MI may decrease the amplitude, hypertrophy increases amplitude

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78
Q

What is the axis of lead I?

A

From RA to LA

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79
Q

What is the axis of lead II?

A

From RA to LL

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80
Q

What is the axis of lead III?

A

From LA to LL

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81
Q

What is a QS wave?

A

Totally negative deflection with no R wave present (not normal)

82
Q

What are the unipolar limb leads?

A

aVR, aVL, aVF

83
Q

How are unipolar limb leads defined?

A

Consist of only one positive electrode, connected to a common central terminal, other end of the axis is at the center of the electrical field/approximate center of the heart

84
Q

Where should lead V1 be placed?

A

4th ICS R of sternum

85
Q

Where should V2 be placed?

A

4th ICS just L of sternum

86
Q

Where should V3 be placed?

A

Midway between V2 and V4

87
Q

Where should V4 be placed?

A

5th ICS in the L MCL

88
Q

Where should lead V5 be placed?

A

Horizontal to v4 in the L AAL

89
Q

Where should V6 be placed?

A

Horizontal to V4 in the L MAL

90
Q

Why should limb leads be placed on the trunk rather than the limbs during continuous ECG monitoring?

A

To minimize artifact from patient motion

91
Q

What color is the L arm electrode?

A

Black

92
Q

What color is the R arm electrode?

A

White

93
Q

What color is the L leg electrode?

A

Red

94
Q

What color is the R leg electrode?

A

Green

95
Q

What color are the precordial electrodes?

A

Brown

96
Q

What electrodes is MCL 1 composed of?

A

RA placed on the L shoulder just below the clavicle, LA placed on the R shoulder just below the clavicle, LL when placed at the 4th ICS just R of the sternal border

97
Q

What does lead MCL 1 show?

A

Right sided view of the heart allowing for differentiation between RBBB and LBBB, L PVCs from R PVCs, R VT from L VT, and supraventricular beats from ventricular escape beats

98
Q

What is MCL 6?

A

Modfied bipolar chest lead approximating V6 and provides a left sided view of the cardiac electrical activity and does the same things as MCL1

99
Q

What electrodes make up the MCL 6 lead?

A

RA/white placed on the L shoulder just below the clavicle, LA/black placed on the R shoulder just below the clavicle, LL/red when placed horizontal to the to the 5th ICS in the L mid-axillary line

100
Q

what are the possible morphologies of the P wave?

A

Positive, negative, or biphasic depending on lead

101
Q

Define the PR segment?

A

Isoelectric line from the end of the P wave to the beginning of the QRS complex representing the electrical impulse traveling through the AV node where it is delayed and then through the ventricular conduction system prior to ventricular depolarization

102
Q

Define PR interval

A

End of the P wave to the beginning of the QRS complex (typically 0.12-0.2 seconds in duration)

103
Q

What is the QRS complex?

A

Represents time required for ventricles to depolarize, from the end of the PR segment to the J point, usually 0.04-0.10 seconds

104
Q

What does the ST segment represent?

A

Early ventricular repolarization, corresponding to phases 1 & 2 of the action potential

105
Q

What affects the length of the ST segment?

A

HR changes, medications, electrolyte disturbances

106
Q

What is an abnormal deviation of the ST segment from the isoelectric line?

A

Elevation greater than 1 mm or depression greater than 0.5 mm in relation to TP segment or PR segment when measured at a point 2 mm beyond the J point

107
Q

What are ST elevation changes typically caused by?

A

Myocardial ischemia/injury, conduction abnormalities, medication

108
Q

What does the T wave represent?

A

Ventricular repolarization, typically has a positive deflection and is rounded and slightly asymmetrical

109
Q

What affects T wave morphology?

A

MI, potassium or calcium, medications, ANS effects

110
Q

What does a U wave represent?

A

Potentially slow repolarization of purkinje fibers

111
Q

What characteristics make up a U wave?

A

Follows T wave, same polarity as T wave but smaller, most common in V3, abnormal prominence suggests electrolyte abnormality or other disturbance

112
Q

What causes changes in the length of the QT interval?

A

Age, sex, changes in HR (slower HR = longer, faster HR = shorter), medications, prinzmetal’s angina, SAH; typical length is 0.32-0.40 for a HR between 60-95

113
Q

What can a prolonged QT interval lead to?

A

Torsades de Pointes

114
Q

What are the characteristics of the TP segment?

A

Isoelectric, follows T or U wave, shortens as HR increases and lengthens as HR decreases

115
Q

What is the measurement of each small box on an ECG?

A

1 mm x 1 mm

116
Q

What is the time measurement of each small block on an ECG?

A

0.04 s

117
Q

What is the time measurement of each large block on an ECG?

A

0.2 seconds

118
Q

How many large blocks equal one second on an ECG?

A

5

119
Q

What is the voltage equivalent of one small block on an ECG?

A

0.1 mV (1 mm)

120
Q

What should each P wave be inspected for?

A

Morphology, P before every QRS?, regular P-P interval, atrial rate

121
Q

What characteristics should each QRS complex be analyzed for?

A

Morphology, R-R interval regular?, ventricular rate

122
Q

Which leads is the QT interval longer in?

A

V2 and V3

123
Q

How is the QT interval measured?

A

Measure the lead with the tallest T waves or in an irregular rhythm the QT interval that follows the longest R-R interval, do not include the U wave if present

124
Q

What is the rule of thumb for a measured QT interval?

A

For heart rates 60-100 bpm, a normal QT interval does not exceed half the R-R interval

125
Q

What is a QTc?

A

QT corrected for a HR of 60 bpm using Bazett’s formula (QT interval/the square root of the R-R interval)

126
Q

True or false, the QT interval is not affected by HR in post menopausal women or gender in children.

A

True

127
Q

What are the criteria for a sinus arrhythmia and what is it the result of?

A

Changes in intrathoracic pressure during breathing; irregular rhythm with the shortest P-P and R-R intervals varying by at least 0.12s from the longest P-P and R-R intervals, rate may be normal or < 60, QT interval varies with HR but all other measurements are normal

128
Q

What are the characteristics of tachydysrhythmias?

A

HR > 100 bpm; Shortenes diastolic time and coronary perfusion time, initially increases CO but eventually results in decreased CO and BP d/t decreased stroke volume, decreases aortic pressure, increases the work of the heart

129
Q

What are the characteristics of a bradydysrhythmia?

A

HR < 60 bpm; diastole is prolonged resulting in adequate coronary perfusion time but may decrease if HR is too slow, reduced MVO2 (work of the heart)

130
Q

What are the characteristics of premature complexes?

A

Occur early d/t ectopy and are followed by a pause; characteristically bigeminy, trigeminy, or quadrigeminy

131
Q

What are the characteristics of an escape complex or rhythm?

A

Occurs after a pause and serves as a latent pacemaker, originates from the AV node, junctional tissue, or ventricular tissue, stop when SA node regains function

132
Q

What are the criteria of a BBB?

A

Rhythm usually regular, ventricular and atrial rates usually equal, consistent P wave morphology with a P wave before every QRS, normal or prolonged PR interval, QRS usually wide (0.12-0.14s) and is constant or has slight variation, ST-T in the opposite direction to the QRS

133
Q

What is the normal ECG configuration of lead I?

A

Positive P wave, small q with R>S, positive T wave, isoelectric ST segment

134
Q

What is the normal ECG configuration of lead II?

A

Positive P wave, small q and R>S, positive T wave, isoelectric ST segment

135
Q

What is the normal ECG configuration of lead III?

A

Variable P wave, small or absent q with R>S, variable T wave, isoelectric ST segment

136
Q

What is the normal ECG configuration for lead aVR?

A

Negative P wave, small/absent/large Q with small/absent r and a large S that may be a QS, variable T wave, and isoelectric ST segment

137
Q

What is the normal ECG configuration for lead aVL?

A

Variable P wave, small/absent/large Q with small/absent/large R and absent or large S, variable T wave, and isoelectric ST segment

138
Q

What is the normal ECG configuration of lead aVF?

A

Positive P wave, small/absent q with small/absent/large R and absent to large S, variable T wave, isoelectric ST segment

139
Q

What is the normal ECG configuration of lead V1?

A

Variable P wave, absent Q, absent/small r, R

140
Q

What is the normal ECG configuration of lead V2?

A

Variable P wave, QRS same as V1 with the R>R in V1, variable T wave, isoelectric ST segment

141
Q

What is the normal ECG configuration of lead V3?

A

Variable P wave, small/absent q, R>/=S, R>R in V2, positive T wave, isoelectric ST segment

142
Q

What is the normal ECG configuration of lead V4?

A

Positive P wave, small/absent q, R>S, R>R in V3, positive T wave, isoelectric ST segment

143
Q

What is the normal ECG configuration of lead V5?

A

Positive P wave, small q, large R (<26 mm), R>R in V4, S

144
Q

What is the normal ECG configuration of lead V6?

A

Positive P wave, small q, large R (<26 mm), S

145
Q

What are the normal measurements of a P wave?

A

Measures 0.08-0.11 seconds in width, <2.5 mm in amplitude

146
Q

What are the normal measurements of the Q wave?

A

Typically <0.04s in duration, depth no more than 2mm in leads I/II/aVL/aVF/V4-6, depth 2-6mm in lead III, large Q in aVR, absent in leads V1-V3

147
Q

What are the criteria for a pathological Q wave?

A

>0.04s in duration, 1/3 the height of QRS amplitude, >25% of R wave amplitude in leads I/II/III/aVF, >15% of R wave amplitude in leads V4-V6, >50% of R wave amplitude in lead aVL; new Q waves are typically associated with the loss of R waves in the same leads

148
Q

What constitutes a pathological ST segment?

A

Elevation >1mm above isoelectric in >/= 2 contiguous leads, depression >0.5-1mm below isoelectric in >/= 2 contiguous leads, convex or coved ST elevation indicative of AMI, concave ST elevation indicative of pericarditis, upsloped ST depression considered non-specific but may indicate CAD, horizontal or downsloping ST depression is significant for UA or NSTEMI

149
Q

What are the normal characteristics of a T wave?

A

Does not exceed 5mm in limb leads and 10 mm in precordial leads, upstroke longer than downstroke, positive in leads I/II/V3-6, variable in leads III/aVL/aVF/V1-V2, and negative in aVR

150
Q

What are the characteristic findings in myocardial ischemia and NSTEMI?

A

Symmetrical T wave inversion, ST depression

151
Q

What is typical of myocardial injury?

A

Convex ST elevation

152
Q

What is typical of myocardial infarction/STEMI?

A

Pathological Q waves

153
Q

What is the difference between subendocardial ischemia and transmural injury?

A

Subendocardial ischemia causes ST depression because the repolarization is still occurring in the usual direction but is then delayed at the area of injury, transmural injury causes completely altered repolarization in which the electrical activity is still moving in the direction of the epicardium

154
Q

What are the stages of infarction?

A

Normal -> ischemia -> injury -> infarction

155
Q

True or false, early repolarization is a normal variant in young adults.

A

True, this causes ST elevation

156
Q

What measurements of ST elevation are pathological in limb leads vs precoridal leads?

A

1mm in limb leads, 2mm in precordial leads

157
Q

List the primary causes of ST elevation

A

Ventricular aneurysm, pulmonary embolism, intracranial hemorrhage, acute MI, early repolarization, pericarditis

158
Q

What are the primary causes of ST depression?

A

Myocardial ischemia, LVH, intraventricular conduction defects, medication (Digoxin), reciprocal changes in leads opposite the area of acute injury, unstable angina

159
Q

What are the typical findings of a posterior MI?

A

Tall R waves and ST segment depression in leads V1-V4 (apply leads V8-9 for definitive diagnosis), may also have tall T waves, associated with lateral and inferior MIs

160
Q

What are the steps to ECG analysis?

A

Rate, rhythm, P waves, QRS complex, PR interval, QRS duration, QT interval, determine QTc (>0.44 associated with 8x risk CVS mortality)

161
Q

What are the criteria for WPW syndrome?

A

Rate dependent on underlying rhythm, regular rhythm unless associated with afib, normal p waves unless afib present, short PR interval, wide QRS with delta wave present

162
Q

What are the criteria for PAC’s?

A

Rate nonspecific, rhythm irregular, P waves present but may be morphologically different in PAC, variable PR interval in the PAC but normal otherwise, normal QRS

163
Q

What are the criteria for atrial tachycardia?

A

Rate 150-250 bpm, regular rhythm, normal P waves but differ in shape from normal sinus P waves, PR interval may be short, normal QRS interval

164
Q

What are the criteria of a supraventricular tachycardia?

A

Rate 150-250, regular rhythm, P waves often buried in proceeding T waves, usually not possible to measure PR interval, normal QRS unless conducted through ventricles abnormally

165
Q

What are the criteria for a paroxysmal supraventricular tachycardia?

A

Rate 150-250, irregular rhythm, P waves frequently buried in preceding T wave, usually cannot measure PR interval, normal QRS but may be wide if abnormally conducted through the ventricles

166
Q

What are the criteria for atrial flutter?

A

Atrial rate of 250-350, ventricular rate is variable, atrial rhythm regular, ventricular rhythm variable, P waves saw-toothed, variable PR interval, QRS usually normal but may look wider if flutter waves are buried inside of it

167
Q

What are the criteria for atrial fibrillation?

A

Atrial rate of 350 per minute or greater, ventricular rate variable, irregular rhythm, no true P waves only chaotic electrical activity, no PR interval, normal QRS

168
Q

What are the criteria for a premature junctional contraction?

A

Rate variable, rhythm irregular, no P wave or retrograde P wave, no PR interval, normal QRS

169
Q

What are the criteria for an accelerated junctional rhythm?

A

Rate 61-100, rhythm regular, buried or retrograde P waves, no PR interval, normal QRS

170
Q

What are the criteria for a junctional tachycardia?

A

Rate 101-180, rhythm regular, buried or retrograde P waves, no PR interval, normal QRS

171
Q

Criteria for a junctional escape rhythm

A

Rate <60, rhythm regular, buried or retrograde P waves, no PR interval, normal QRS

172
Q

Define bigeminy

A

Ectopy every other beat

173
Q

Define trigeminy

A

Ectopy every third beat

174
Q

Define quadrigeminy

A

Ectopy every fourth beat

175
Q

Criteria for monomorphic ventricular tachycardia

A

Rate 100-250, rhythm regular, no P waves or not associated with the QRS complex, no PR interval, wide QRS

176
Q

criteria for polymorphic ventricular tachycardia

A

Rate 100-250, regular or irregular, no P wave or not associate with the QRS complex, no PR interval, wide QRS

177
Q

Criteria for ventricular fibrillation

A

Indeterminate rate, chaotic rhythm, no P waves, no PR interval, no QRS

178
Q

Criteria for first degree AV block

A

Rate dependent on underlying rhythm, regular rhythm, normal P waves, prolonged PR interval, normal QRS complex

179
Q

Criteria for a second degree AV block type I (Wenckebach)

A

Rate dependent on underlying rhythm, regular atrial rhythm, irregular ventricular rhythm, normal P waves but more P waves than QRS complexes, progressively longer PR interval until one P wave is blocked and the QRS is dropped, normal QRS

180
Q

Criteria for a second degree AV block type II (mobitz II)

A

Atrial rate usually between 60-100, slower ventricular rate, regular atrial rhythm, regular or irregular ventricular rate, PR interval normal or prolonged but constant, QRS may be normal but is usually wide

181
Q

Criteria for third degree AV block

A

Atrial rate 60-100, ventricular rate 40-60 (slower than atrial rate), usually a regular rhythm with independent atria and ventricles, normal P waves but more than QRS complexes, PR interval varies greatly, normal or wide QRS

182
Q

BBB Criteria

A

Usually regular rhythm, any rate but equal atrial and ventricular, normal or prolonged PR interval, wide QRS, ST-T in opposite direction to terminal portion of QRS complex

183
Q

RBBB QRS Morphology

A

V1: rSR’ with the R rabbit ear taller than the L, VAT >0.02 s, inverted T wave; V6: qRS with large broad S wave also seen in leads I and aVL, normal VAT, upright T wave

184
Q

RBBB Criteria

A

QRS >0.10s, normal or R axis deviation, broad S in leads I/aVL/V5/V6, RSR’ in lead V1 with R’ taller than R, qRS pattern in V5 and V6, ST-T opposite of terminal portion of QRS

185
Q

RBBB etiologies

A

Normal variant, congenital heart disease, RVH with pulmonic stenosis or pHTN, acute dilation of the R ventricle, coronary insufficiency, degenerative disease in conduction system

186
Q

LBBB QRS Morphology

A

V1: negative complex with QS or rS with deep/wide S sharply downsloping, normal VAT, upright T; V6: positive complex with R or M complex and absent septal q wave, VAT markedly delayed, T wave inverted

187
Q

LBBB Criteria

A

wide QRS (>0.10), QRS predominantly negative in leads V1 and V2, predominantly positive in V5 and V6 and often notched, absence of small q waves in leads I/aVL/V5/V6, wide monophasic R waves in I/aVL/V1/V5/V6

188
Q

LBBB etiologies

A

MC organic heart disease (HTN, ASCVD), anterior MI, valvular disease (AS, etc), rheumatic heart disease, cardiomyopathy, HF, LVH, coronary insufficiency, trauma, cardiac tumors, fibrosis of conduction system

189
Q

What are the ECG features of LVH?

A

Tall R waves in L ventricular leads, deep S waves in R ventricular leads, delayed intrinsiciod deflection in V6 (time from QRS onset to peak R is >/= 0.05sec), widened QRS/T angle (L ventricular strain pattern or ST-T oriented opposite to QRS direction), L shift in frontal plane QRS axis, evidence of L atrial enlargement

190
Q

What are the Estes criteria for LVH?

A

Diagnostic requires 5 points, probable requires 4 points: R or S in limb leads >/= 20 mm (3 points) S in V1 or V2 >/= 30 mm (3 points) R in V5 or V6 >/= 30 mm (3 points) ST-T abnormalities with Digitalis (3 points) ST-T abnormalities without Digitalis (1 point) Left atrial enlargement in V1 (3 points) Left axis deviation (2 points) QRS duration 0.09 seconds (1 point) Delayed intrinsicoid deflection V5 or V6 (>0.05s) (1 point)

191
Q

What are the Cornell Voltage criteria for LVH?

A

Sensitivity of 22%, specificity of 95% S in V3 + R in aVL > 24mm (men) S in V3 + R in aVL > 20 mm (women)

192
Q

What are the limb lead voltage criteria for LVH?

A

R in aVL >/= 11 mm If LAD, R in aVL >/= 13 mm plus S in III >/= 15 mm R in lead I + S in lead III > 25 mm

193
Q

What are the chest lead criteria for LVH?

A

S in V1 + R in V5 or V6 >/= 35 mm

194
Q

What are the common diagnostic criteria for RVH?

A

R in V1 >/= 0.7mV QR in V1 R/S in V1 >1 with R >0.5mV R/S in V5 or V6 >0.7mV R in V5 or V6 >/=0.4mV with S in V1 >/= 0.2mV RAD >/= 90 degrees S1Q3 pattern S1S2S3 pattern P pulmonale

195
Q

What must there be at least one of in the presence of a narrow QRS for the diagnosis of RVH?

A

RAD greater than 90 degrees in the presence of a disease capable of causing RVH, R in aVR >/= 5mm, R in aVR > Q in aVR

196
Q

What are the specific features of RVH found in lead V1?

A

R/S ratio > 1 and negative T wave, qR pattern, R > 6 mm OR S <2mm OR rSR’ with R’ >10mm

197
Q

What are chest lead criteria for RVH?

A

R in V1 + S in V5 or V6 10mm R/S ratio in V5 or V6 <1 R in V5 or V6 < 5mm S in V5 V6 > 7mm *ST segment depression and T wave inversion in R precordial leads is usually seen in severe RVH such as in pulmonary stenosis and pulmonary hypertension

198
Q

What is the simplified ECG criteria for RVH?

A

V1-2: R taller than S, strain pattern V5-6: deep S wave, no strain pattern RAD *strain pattern denotes a change in repolarization shown by a downward sagging ST segment with inverted T wave when seen in any lead with a tall R wave (leads III, aVF, V1-2)

199
Q

What is the simplified ECG criteria for LVH?

A

V1-2: deep S wave, no strain pattern V5-6: tall R wave, strain pattern, also in leads I and aVL *sum of S in V1 or V2 + R in V5 or V6 = 35 mm or more LAD

200
Q

What does RVH commonly result from?

A

COPD, pulmonic stenosis, and systemic hypertension

201
Q

What does LVH typically result from?

A

Chronic systemic HTN, AS *increased risk for MI and/or SCD, more likely to have ventricular ectopy which additionally may be difficult or impossible to suppress with medication

202
Q

What are the characteristics of a normal Q wave?

A

Generally <0.04s in duration Depth < 2mm in leads I, II, aVL, aVF, V4-6 Depth 2-6mm in lead III Large Q in aVR Absent Q in leads V1-3

NEHI/CMC Cardiology (6 decks)

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