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History taking and physical examination > ECG > Flashcards

ECG Flashcards

1
Q

What can we find on the ECG?

A
  1. Waves -> załamki
    1) P
    2) Q
    3) R
    4) S
    5) T
    6) U
  2. Points -> J
  3. Segments -> odcinki
  4. Intervals -> odstępy
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2
Q

U wave origins

A
  1. The exact source of the U wave remains unclear.
  2. The most common theories for the origin are:
    1) Delayed repolarization of Purkinje fibers
    2) Prolonged repolarisation of mid-myocardial M-cells
    3) After-potentials resulting from mechanical forces in the ventricular wall
    4) The repolarization of the papillary muscle
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3
Q

J point

A
  1. Junction of the QRS and ST segment
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4
Q

Segments in ECG

A
  1. PR
  2. ST
  3. TP
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5
Q

Intervals in ECG

A
  1. PR-> from the beginning of P to the beginning of QRS -> (po polsku odstęp PQ)
  2. QT -> from the beginning of QRS to the end of T
  3. QRS interval = QRS complex
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6
Q

Limb electrodes in ECG location

A
  1. Red -> right arm
  2. Yellow -> left arm
  3. Green -> left leg
  4. Black -> right leg
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7
Q

Precordial electrodes location

A

V1 -> fourth right intercostal space (4R) in sternal line
V2 -> 4L in sternal line
V3 -> halfway between V2 and V4
V4 -> 5L in midclavicular line
V5 -> directly lateral to V4 in anterior axillary line
V6 -> directly lateral to V4 in midaxillary line

Women -> V4, V5, V6 -> should be positioned on the chest wall beneath the breast

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8
Q

Quantity of lines in normal 25 cm/s ECG

A
  1. Horizontal lines
    - > 1 mm = 0,04 s = 40 ms
    - > 5 mm = 0,2 s = 200 ms
  2. Vertical lines
    - > 1 mm = 0,1 mV
    - > 10 mm = 1,0 mV
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9
Q

Every ECG examination algorithm

A
  1. Quality of reading
  2. General aspects
  3. Waves, intervals and segments morphology
  4. Rhythm
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10
Q

ECG Quality of reading examination algorithm

A
  1. Calibration -> should be 1 mV= 10 mm
  2. Paper speed -> should be 25 mm/s
  3. Electrode to skin contact -> back and forth movement of the isoelectric line
  4. Artifacts -> movement of patient
  5. Correctness of electrode placements
    1) reversals
    2) wrong placement especially V1 and V2
  6. Position of the patient -> ask if something is wrong
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11
Q

ECG examination algorithm General aspects

A
  1. Rhytm
  2. Rate
  3. Regularity
  4. Heart axis
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12
Q

ECG examination algorithm waveform analysis algorithm

A
  1. General contours
  2. Durations
  3. Positive and negative amplitudes
  4. Axes in frontal and transverse planes
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13
Q

Second to beats/minute exchange rate

A
  1. 0,2 s (one big square) = 300 bpm
  2. 75 bpm = 0,8 s (4 big squares)
  3. Algorithm to calculate HR:
    HR=300/x [bpm],

where x = number of big squares between one R of QRS complex and the next

  1. Algorithm to calculate HR when >100 bpm:
    HR=1500/y [bmp], where y = number of small squares
  2. If HR< 100 bpm big squares are sufficient
  3. HR=100 bpm x=3
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14
Q

ECG examination algorithm Heart rate and regularity

A
  1. Look to intervals RR in all leads and see if they are +/- equal
    1) if they are +/- equal -> HR is regular (variability of RR intervals should be ≤0.12 s)
    2) they are almost never equal -> differences in phases of respiratory cycle
  2. If HR is regular calculate HR between two succeeding R waves
  3. If HR is irregular:
    1) count the number of cardiac cycles in 6 seconds (30 big squares) and multiply by 10
    - > often there are markers at 3 second intervals (down)
    2) the number of cycles over a particular interval of time should be counted -> if 6s is not sufficient
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15
Q

Identification of heart axis

A

-> use only limb leads

  1. Identify the transitional lead
    - > lead in which QRS complex has the most equal positive and negative components
  2. Identify the lead that is oriented perpendicular (90 degrees) to the transitional lead using hexaaxial reference system
  3. Consider predominant direction (positive or negative) of lead from step 2 -> if it’s positive -> the axis is positive and vice versa
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16
Q

Heart axis QRS -> easier determination

A
  1. I + aVF +
    - > 0-90 degrees
2. I+ aVF -
       II + 
-> 0-(-30) degrees 
       II -
-> -30-(-90) degrees
  1. I - aVF +
    - > 90-180 degrees
  2. I- aVF -
    - > -90-(-180) degrees
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17
Q

Hexaxial reference system

A 
aVL: -30 and +150
I: 0 and 180
aVR: -150 (positive) and +30
II: +60 and -120
aVF: +90 and -90
III: +120 and -60
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18
Q

Degrees in hexaxial reference system -> what they mean

A
  1. -30 to +90
    1) is normal axis of QRS complex
    2) I and II -> positive QRS
  2. +90 to +180
    1) axis deviated right (RAD -> right-axis deviation)
    2) I -> negative QRS
    3) II -> positive QRS
  3. -30 to -90
    1) axis deviated left (LAD -> left-axis deviation)
    2) I -> positive QRS
    3) II -> negative QRS
  4. -90 to 180
    1) EAD -> extreme-axis deviation
    - > rarely
    2) I -> negative QRS
    3) II -> negative QRS
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19
Q

Frontal plane axis -> differences between people

A

1) Age
1. Neonate -> rightward
2. Children-> vertical position
3. Adulthood-> leftward

2) Body posture
1. Slim -> more vertical
2. Fat -> more horizontal

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20
Q

ECG examination algorithm Waves, segments and intervals morphology

A
  1. P wave
  2. PR interval
  3. QRS complex
  4. ST segment
  5. T wave
  6. U wave
  7. QT interval
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21
Q

P wave morphology ECG

A
  1. Location:
    1) before each QRS
  2. General contour:
    1) Monophasic or biphasic
  3. Duration
    1) normally ≤ 0.12 s
  4. Amplitude
    1) normally no more than:
    1. 0.25mV in frontal plane leads
    2. 0.3 mV in precordial leads
    3. V1: positive ≤0.15 mV
    negative ≤0.1 mV
  5. Axis
    1) positive or negative
    2) axis of P-wave
    - > could be determined according to the QRS
    - > normal limits: 0 to +75 degrees
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22
Q

P wave morphology ECG - general contour

A
  1. Monophasic in all leads except V1 and possibly V2
  2. In V1 -> biphasic
  3. RA and LA differential
    1. Beginning (1/3) -> RA
    2. Middle (2/3) -> both RA and LA
    3. End (3/3) -> LA
    - > especially important to determine in V1
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23
Q

P wave morphology ECG - axis

A
  1. Entirely upright -> in leftward- and inferiorly oriented leads (to sinus rhythm: I, II, aVF+, aVR -)
    1) I, II
    2) aVF
    3) V4, V5, V6
  2. Negative in:
    1) aVR
  3. Biphasic in V1 and possibly V2
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24
Q

PR interval morphology ECG

A
  1. Measures the time required for an electrical impulse to travel from SA to ventricular myocardium
  2. Durations -> adult: 0.12 to 0.20 s (childhood depends on age, can be <0.12 s)
  3. Varies highly with autonomic system activity
    - > a major potion of PR interval depends on AV
    - > Varies with HR
  4. PR segment -> should be isoelectric
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25
Q

QRS complex morphology ECG

A
  1. General contour
    1) should be higher (more mV) than P or T wave
    2) should be peaked rather than round
    3) see which waveform (monophasic, …)
    4) consider Q, R and S waves separately
  2. Duration -> 0.07-0.11 s
  3. Amplitudes
    1) other card
  4. Axis
    1) positive or negative
    2) plane axis -> is the axis of heart
    3) transverse axis
26
Q

QRS complex waveforms

A
  1. Monophasic
    1) R
    2) QS
  2. Biphasic
    1) RS
    2) QR
  3. Triphasic
    1) RSR’
    2) QRS
27
Q

Q wave morphology ECG

A
  1. Presence
    1) absence abnormal in: V5, V6
    2) presence abnormal in: V1, V2, V3
  2. Duration limits -> other card
  3. Amplitude
    1) In I, II, aVL, aVF and V4-V6 a normal Q wave is very small
    2) In right-oriented leads (III and aVR) Q wave of any size is normal
    3) Enlargement of Q wave (more than 1/3 of the amplitude of the R wave or more than 0.1 mV)!!! -> in many conditions:
    1) loss of myocardial tissue (infarction)
    2) enlargement of ventricular myocardium
    3) abnormalities of ventricular conduction
28
Q

Q wave normal duration limits ECG

A 
Leads:
I: < 0.03
II: < 0.03
III: no limits
aVR: no limits 
aVL: < 0.03
aVF: < 0.03
V1: any Q is abnormal
V2: any Q is abnormal
V3: any Q is abnormal
V4: < 0.02
V5: < 0.03
V6: < 0.03
29
Q

R wave morphology ECG

A
  1. Increase in amplitude and duration in V1 to V4 or V5
    1) reversal of this with larger V1 and 2 -> can be in RV hypertrophy
    2) accentuation with large R wave in V5 and V6 -> can be in LV hypertrophy
    3) loss of R-wave progression from V1 to V4 may indicate loss of LV myocardium (eg. infarction)
30
Q

S wave morphology ECG

A
  1. Progression-> should be:
    1) large in V1
    2) larger in V2
    3) then progressively smaller from V3 to V6

-> abnormalities in this progression suggest hypertrophy or infarction

31
Q

QRS complex duration

A
  1. 0.07 to 0.11 seconds
  2. Is termed QRS interval
  3. Beginning and end of the QRS may be isoelectric in some leads -> multi-lead comparison is necessary -> often end (point J) is indistinct in the leads, particularly precordial
  4. Intrinsicoid deflection should be examined
  5. It usually is slightly longer in males than in females
32
Q

Prolongation of QRS duration

A
  1. LV hypertrophy
  2. Abnormalities in intraventricular impulse conduction
  3. Ventricular side of origin of cardiac impulse
33
Q

Intrinsicoid deflection

A
  1. Duration between the earliest appearing Q or R wave to the peak of the R wave
  2. Represents the time required for the electrical impulse to travel from the endocardial to the epicardial surfaces of the ventricular myocardium
  3. Measured in precordial leads
    - > in V1 and V2 should be ≤0,035 s
    - > in V3-V6 should be ≤0,045s
34
Q

QRS amplitude depends on:

A
  1. age (increasing until 30 years old then decreasing)
  2. sex -> larger in males
  3. physical activity
  4. body type -> larger in slender

Abnormally Large:

  1. Intraventricular conduction abnormalities
  2. Ventricular enlargement

Abnormally small:
7. In any condition that increases the distance between the myocardium and the recording electrode eg. thick chest wall

35
Q

QRS amplitude

A
  1. Wide normal limits
    1) No upper border -> even 4 mV is seen physiologically
    2) Lower border -> abnormal is:
    A) <0.5 mV in limb leads
    B) <1.0 mV in precordial leads
  2. Measured between the peaks of the tallest positive and negative waveforms in QRS complex
36
Q

Direction of QRS

A
  1. Always should be positive in:
    1) I, II
    2) aVL
    3) V4, V5, V6
  2. Should be negative in
    1) aVR
    2) V1
    3) V2
  3. In other (III, aVF, V3) can be either
37
Q

Transverse axis of QRS

A
  1. Algorithm similar to frontal plane axis
  2. Transverse lead -> usually V3 or V4
  3. Then perpendicular lead is respectively V6 or V1
  4. Normal axis: 0 to -60 degrees
38
Q

ST segment

A
  1. Represents ventricular repolarization -> phase 1 and 2
  2. Should be horizontal and isoelectric (at TP segment level) but:
    1) may be displaced as much as 0.1 mV from the TP segment in the direction of T wave
    - > early repolarization syndrome -> normal variant
    2) occasionally in young males may normally show even greater elevation in leads V2 and V3
    3) Abnormally prolonged QRS May alter ST segment
    4) slight upsloping, downsloping or horizontal depression may occur as a normal variant
  3. Duration -> is influenced by factors that alter the duration of ventricular activition
39
Q

Significant elevation of ST -> norms

A

1) in V2 and V3
1. Women ≥0.15 mV
2. Men <40 years: ≥0.25 mV
3. Men ≥40: ≥0.2 mV
2) in other leads: ≥0.1 mV

3) Measured in point J

40
Q

Significant decrease of ST -> norms

A
  1. V1, V2, V3 ≥0.05 mV
  2. Other leads ≥0.1 mV
  3. Measured in point J
41
Q

ECG -> T wave morphology

A
  1. General contour
  2. Duration-> is not usually measured (QT interval is measured)
  3. Amplitudes
    1) shouldn’t exceed 0.5 mV in limb leads
    2) shouldn’t exceed 1.5 mV in precordial leads
    (But can in young people with vagotonia)
  4. Axis
    1) should be evaluated in relation to QRS
    2) can be measured analogically to QRS axis
    3) QRS-T angle is number of degrees between axis of QRS and T wave -> normally doesn’t exceed 45 degrees in frontal plane
42
Q

ECG -> T wave morphology -> General contour

A
  1. Always should be positive directed in:
    1) I, II
    2) V4-V6
  2. Always should be negative in aVR
  3. Can be either way:
    1) III
    2) aVL and aVF
    3) V2 and V3 -> these can be negative only if amplitude of V2 biphasic (initially positive then negative)
  4. In V1 should be biphasic
  5. Light peaking may occur as normal variant
  6. Should be directed in the same direction as QRS complex
  7. Ascending part should be less steep than descending part
43
Q

Changes in amplitude of T wave

A
  1. Age -> it diminishes
  2. Sex -> larger in males
  3. Tends to vary with QRS amplitude
  4. Should be always bigger than U wave if it’s present
44
Q

ECG -> U wave morphology

A
  1. Normally either absent or very small
  2. Normally oriented in the same direction as the T wave with +/- 10% of its amplitude
  3. Usually most prominent in V2 or V3
  4. Larger in slow rhythm
45
Q

ECG -> QT interval

A
  1. Measures the duration of electrical activation and recovery of the ventricular myocardium
  2. Varies inversely with HR -> the “normality” of the QT interval can be determined only by correcting for HR
  3. QTc -> corrected QT interval
    - > is included in normal ECG analysis
  4. QTc duration should be ≤ 0.46 s
46
Q

cQT formulae

A
  1. Bazett’s formula:

QTc = QT/ √RR

  1. Hodges and coworkers’ formula (preferable)

QTc = QT + 1,75*(VR-60)/1000

  • > all in [s]
  • > RR -> interval duration between two consecutive R waves [s]
  • > VR -> ventricular rate
47
Q

QTc interval normal differences

A
  1. Females > males

2. Increases with age

48
Q

Normal sinus rhythm rate

A

60-100 bpm

<60 -> bradycardia
>100 -> tachycardia

49
Q

Sinus arrhythmia

A
  1. Normal variation in cardiac rhythm that cycles with the phases of respiration
  2. Inspiration -> accelerates
  3. Expiration -> slows
50
Q

Cardiac rhythm examination

A

Factors that should be considered:

  1. Cardiac rate and regularity
  2. P-wave axis
  3. PR-interval
  4. Morphology of QRS complex
  5. QTc interval and U wave
51
Q

Cardiac rhythm examination Cardiac rate and regularity

A
  1. Sinus rhythm-> should be 60-100 or there should be explanation for increase (exercise) or decrease (sleep, vagotonia in athletes)
  2. Should be +- regular (variability between RR intervals should be ≤0.12s)
  3. There should be variations with respiratory cycles
  4. If HR<60 and >100 or it’s irregular loss of sinus rhythm should be considered
52
Q

Cardiac rhythm examination P-wave axis

A
  1. Alterations of P-wave axis to either >+75 or
53
Q

Cardiac rhythm examination PR-interval

A
  1. Adult norms for PR interval: 0.14 to 0.21 s

2. No P wave -> PR interval cannot be determined-> obvious abnormality of cardiac rhythm

54
Q

Abnormally short PR interval

A

1) with abnormal P wave indicates:
1. displacement of impulse formulation to a position closer to the AV node than to SA node
2. With inverse P-wave-> ectopic atrial rhythm

2) with normal P-wave indicates:
1. Abnormally rapid conduction pathway within the AV node or
2. Presence of abnormal bundle of cardiac muscle connecting the atria to the Bundle of His -> ventricular pre-excitation

55
Q

Abnormally long PR interval

A
  1. with normal P wave:
    1) delay of impulse transmission between SA and ventricular myocardium -> usually in AV node
    2) 1st degree AV block
  2. with abnormal P wave:
    1) reverse activation -> from ventricles to atria (impulse originates from ventricles)
    - > P wave may be identified as a distortion of the T wave (reverse P-wave)
    - > it’s called junctional rhythm
56
Q

Cardiac rhythm examination Morphology of QRS complex

A
  1. Normal P wave with short PR interval and abnormal QRS complex
    1) no AV nodal transition -> there is bypass that directly enters the ventricular myocardium-> ventricular pre-excitation
  2. Normal P wave with normal PR interval with abnormal QRS complex (at the end)
    • > inter-ventricular conduction delay -> abnormality in bundles branches (in one -> normal cardiac rhythm with abnormal QRS, in both -> abnormal rhythm)
  3. Abnormally prolonged QRS with the absence of P wave -> ventricular rhythm
57
Q

Cardiac rhythm examination QTc interval and U wave

A

Look for:

  1. Elevation of ST segment
  2. Increase or decrease of T-wave amplitude
  3. Prolongation of QTc interval
  4. Increase in U wave
58
Q

Pacemaker activity -> cardiac cells

A
  1. SA 60-100 beats/min
  2. Atrial cells 55-60 beats/min
  3. AV 45-50 beats/min
  4. His bundle and it’s branches 40-45 beats/min
  5. Purkinje cells 35-40 beats/min
  6. Cardiomyocyts 30-35 beats/min
59
Q

SA and AV noodles arterial supply

A
  1. SA
    1) 59% right coronary artery
    2) 38% left coronary artery
    3) 3% both arteries
  2. AV
    1) always right coronary artery
60
Q

Tp wave

A
  1. Caused by repolarization of atria
  2. Usually covered by QRS complex but eg. when PR interval increases -> can be visible
  3. Its amplitude should be opposite to P wave

History taking and physical examination (12 decks)

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