Ekg Theory

Front 1

normal ecg parameters (10 points)?

Back 1

1. 12 leads present
2. rhythmic
3. heart rate= 60-100bpm
4. source is sinus node
5. PRint= .12-.2s
6. QRS= .08-.12s, R increases from V1-V6 (smaller than S in V1 and V2 but bigger in V5 and V6), R is less than 25mm, S is less than 25mm
7. STseg= neither elevated nor depressed
8. T wave= not greater than 1/2 of QRS, inverted in avR and V1, III (with small Q and goes away if breath is held), V2 (young people), and V3 (blacks)
9. QTint= .35-.43s (inversely proportional to heart rate)
10. MEA= 0-90 degrees (-values L shift, +values R shift)

Front 2

possible problems if abnormal QRS?

Back 2

incorrect calibration, LVH/RVH, posterior MI, WPW, dextrocardia, BBB

Front 3

possible problems if elevated or depressed STseg?

Back 3

elevated: AMI, prinzmetal's angina, pericarditis, LV aneurysm, high take-off
depressed: ischemia, posterior AMI, digitoxin/quinidine, LVH/RVH + strain

Front 4

possible problems if T is too tall, too small, or inverted?

Back 4

tall: hyperkalemia, AMI (posterior in ant.leads V1-V3, anterior in ant.leads V1-V3)
small: hypokalemia, pericardial effusion, hypothyroidism

Front 5

possible problems if QTint is shorter or longer?

Back 5

shorter: hypercalcemia, digoxin
longer: hypocalcemia and acute myocarditis (maybe also, AMI, cerebral injury, LVH/RVH, hypothermia)

Front 6

describe how the leads look at the heart.

Back 6

4 limb electrodes to create 6 limb leads: coronal plane
I - straight L
II - R foot
III - L foot
avR - R shoulder
avL - L shoulder
avF - inferior surface
6 chest leads: transverse plane
V1 - big L angle
V2 - small L angle
V3 - anterior surface
V4 - LV anterior surface
V5 - small R angle
V6 - big R angle
______________________________
positive deflection= electrical impulse flowing towards the lead

Front 7

describe how the impulses are generated from the sinus node, atrioventricular node, and from various ecotopic sites.

Back 7

sinus node= 60-100bpm; you're seeing the atrial depolarization as the P wave
atrioventricular node= 40-60bpm; you're seeing the PRint as the time it delays the electrical impulse in case of rapid beats + depolarization traveling from SA, through the atria, and through the AV
bundle of His= down the septum with the left side first, seen as Q wave, R wave (bigger because LV depolarization is bigger than RV), and S wave (bigger in R sided leads because LV depolarization moves away from them) as seen as a transition in the chest leads
ectopic sites= irregular QRS morphology

Front 8

describe the repolarization.

Back 8

STseg= transient period where no impulses are passed
T wave= repolarization of ventricles
QTint= total time for reactivating the ventricles and recovery to resting state
U wave= septum repolarization or slow repolarization of ventricles, seen in V2-V4

Front 9

3. heart rate
which conditions present with bradycardia?

Back 9

(less than 6 QRSs in 6s)
1. sinus bradycardia
2. sick sinus syndrome
3. 2nd/3rd degree AV block
4. escapes: AVj(x), ventricular, asystole
5. beta blockers, calcium antagonists, digoxin, adenosine

Front 10

3. heart rate
which conditions present with tachycardia?

Back 10

(more than 10 QRSs in 6s)
NARROW: supraventricular
1. sinus tachycardia
2. atrial tachycardia
3. atrial flutter
4. atrial fibrillation
5. AV re-entry tachycardia
BROAD: ventricular
1. supraventricular causes if abberent conduction is also present
2. ventricular tachycardia
3. accelerated idioventricular rhythm
4. torsades de pointes
CHAOTIC:
1. ventricular fibrillation

Front 11

4. sinus rhythm
sinus bradycardia

Back 11

1.
2.
3. less than 60bpm
4.
5.
6.
7.
8.
9.
10.
causes? digoxin, beta blockers, ischemia, MI, hypothyroidism, hypothermia, obstructive jaundice, uraemia, high intracranial pressure, SSS, K+/Ca2+ abnormalities

Front 12

4. sinus rhythm
sinus tachycardia

Back 12

1.
2.
3. more than 100bpm
4.
5.
6.
7.
8.
9.
10.
causes? anxiety, pain, fear, fever, exercise, adrenaline, alcohol, ischemia, AMI, heart failure, pulmonary embolism, fluid loss, anaemia, hyperthyroidism

Front 13

4. sinus rhythm
sinus arrhythmia

Back 13

1.
2. arrhythmic
3. 75bpm and 90bpm
4.
5.
6.
7.
8.
9.
10.
causes? under the age of 40, inspiration/expiration and harmless

Front 14

4. sinus rhythm
sick sinus syndrome (SSS)

Back 14

1.
2. arrhythmic
3. sinus bradycardia, then sinus tachycardia as an escape, atrial escape if sinus arrest, sinoatrial block with gaps may occur, +/- atrial tachycardia, atrial flutter, atrial fibrillation, AV node blocks
4.
5.
6.
7.
8.
9.
10.
causes? fibrosis of sinus node and conducting system, ischemia, digoxin, quinidine, beta blockers, cardiomyopathy, amyloidosis, myocarditis

Front 15

4. non-sinus rhythm
atrial tachycardia

Back 15

1.
2.
3. more than 100bpm (120-250bpm but above 200bpm AV block occurs to delay this)
4. atrial ectopic= abnormally shaped P waves
5.
6.
7.
8.
9.
10.
causes? digoxin, ischemia, rheumatic heart disease, cardiomyopathy, SSS, COPD

Front 16

4. non-sinus rhythm
atrial flutter

Back 16

1.
2. rhythmic
3. 300 F waves/m with 150/100/75bpm (so 5 flutter waves/s and 2:1, 3:1, or 4:1 QRS rate respectively because of an AV block to delay this)
4. re-entry circuit within the atria every .2s (1 node with extra conduction fiber)
5.
6.
7.
8.
9.
10.
causes? (same as fibrillation) hypertension, ischemia, hyperthyroidism, SSS, alcohol, rheumatic mitral valve disease, cardiomyopathy, atrial septal defect, pericarditis, myocarditis, pulmonary embolism, cardiac surgery, idiopathic waves
measuring? carotid sinus massage or adenosine will highlight this change by increasing the degree of AV block and making the sawtooth baseline easier to see; also, converted to sinus rhythm with DC cardioversion and overdrive atrial pacing

Front 17

4. non-sinus rhythm
atrial fibrillation

Back 17

1.
2. arrhythmic
3. 350-600 f waves/m with 120-180bpm
4. no P waves because multiple atrial ectopics cause only low-amplitude oscillations
5.
6.
7.
8.
9.
10.
causes? (same as flutter) hypertension, ischemia, hyperthyroidism, SSS, alcohol, rheumatic mitral valve disease, cardiomyopathy, atrial septal defect, pericarditis, myocarditis, pulmonary embolism, cardiac surgery, idiopathic waves
variations? paroxysmal, permanent, or persistent

Front 18

4. sinus rhythm
AV re-entry tachycardia (WPW)

Back 18

1.
2. rhythmic
3. episodes 188bpm (lose delta wave)
4. P wave is after the RS
5. narrow RS complexes
6.
7.
8.
9.
10.
causes? second pathway inside AV node (dual) or outside of AV node (accessory) leading to re-activation of AV node= WPW

Front 19

4. non-sinus rhythm
AV nodal re-entry tachycardia

Back 19

1.
2.
3. 130-250bpm
4. sinus but inverted P not always seen (maybe after the QRS)
5.
6. narrow QRS complexes (broad if existing with BBB, looking similar to VT)
7.
8.
9.
10.
causes?

Front 20

4. non-sinus rhythm
ventricular tachycardia

Back 20

1.
2.
3.
4. more than 120bpm
5.
6. broad QRS
7.
8.
9.
10.
causes? re-entry circuit, increased automaticity of ventricular focus, AMI, ischemia, hypertrophy, dilation, mitral valve prolapse, myocarditis, congenital heart disease, electrolyte disturbance, pro-arrhythmic drugs, idiopathic

Front 21

4. non-sinus rhythm
accelerated idioventricular rhythm

Back 21

1.
2.
3. 60bpm (slow form of VT)
4. ventricular focus
5.
6.
7.
8.
9.
10.
causes? infarcted area acts as ventricular focus, AMI

Front 22

4. non-sinus rhythm
torsades de pointes

Back 22

1.
2.
3. 270bpm (polymorphic form of VT that can lead to V fibrillation)
4.
5.
6. broad QRS
7.
8.
9.
10.
causes? anti-arrhythmic drugs, electrolyte abnormality, hereditary syndromes, +/- long QT interval

Front 23

4. non-sinus rhythm
ventricular fibrillation

Back 23

1.
2. arrhythmic
3.
4. ventricular foci (medical emergency)
5.
6. chaotic QRS complexes
7.
8.
9.
10.
causes? AMI, electrolyte and acid-base abnormalities usually follow

Front 24

5. PRint conduction disturbance
sinoatrial block: 1st,2nd,3rd

Back 24

1.
2. irregularly regular
3.
4. occassional missing P waves but still sinus otherwise
5. failure of P wave, followed by gap, then next P as expected
6.
7.
8.
9.
10.
causes? problem with the sinus node

Front 25

5. PRint conduction disturbance
atrioventricular block: 1st, 2nd:mobitz 1,2,2:1, 3rd, high grade

Back 25

1.
2.
3.
4.
5. longer PRint (varies with each type)
6. some QRS fail to be conducted
7.
8.
9.
10.
causes? problem with the bundle of his

Front 26

6. QRS conduction disturbance
bundle branch block or left sided hemiblock

Back 26

1.
2.
3.
4.
5.
6. 2 R peaks in one complex (the mirror of 2 S is seen in the opposite chest leads)
7.
8.
9.
10.
causes?

Front 27

2. rhythmic
escape rhythms

Back 27

1.
2.
3. 40-60bpm AV, less than 40bpm ventricular
4. if no P wave because sinus fails, then atrioventricular junction or ventricles create the impulse rhythm
5. none
6. AV is identical, V is broad QRS
7. scooped if ventricular
8.
9.
10.
causes?

Front 28

2. arrhythmic
ectopic beats

Back 28

1.
2.
3.
4. if sinus, then P, but otherwise AV or ventricular, both of which may travel retrograde and create inverted P waves
5.
6. earlier than expected; narrow if AV and broad if ventricular
7.
8.
9.
10.
causes?

Front 29

10. mea
quick method of determining?

Back 29

if QRS in lead I=positive, then axis is between +/-90 (perpindicular) and if in lead II=positive, then axis is between -30/+150. combined, it only leaves the area between -30 and +90, which is normal.
I+,II- = left axis deviation
I-,II+ = right axis deviation

Front 30

10. mea
which diseases associated with left axis deviation?

Back 30

1. LAHB
2. WPW
3. inferior MI
4. ventricular tachycardia

Front 31

10. mea
which diseases associated with right axis deviation?

Back 31

1. RVH
2. WPW
3. anterolateral MI
4. dextracardia
5. LPHB

Front 32

4. sinus impulse
what can cause the P wave to be absent?

Back 32

1. no coordinated atrial activity= atrial fibrillation, sinus arrest, SA block, hyperkalemia
2. they're hidden by= AV or ventricular tachycardia (escape rhythm); VT also produces post-QRS P waves via retrograde conduction; atrial flutter
*** if intermittently absent= sinus arrest or SA block

Front 33

4. sinus impulse
what can cause the P wave to be inverted?

Back 33

1. abnormal atrial depolarization= atrial ectopics, AV junctional rhythms, VT, V ectopics
2. dextrocardia

Front 34

4. sinus impulse
what can cause the P wave to be too tall?

Back 34

right atrial enlargement.

causes? pulmonary hypertension, pulmonary stenosis, tricuspid stenosis

Front 35

4. sinus impulse
what can cause the P wave to be too wide?

Back 35

left atrial enlargement.

causes? mitral valve disease, LVH (from hypertension, aortic valve disease, hypertrophic

Front 36

5. PRint
what can cause this to decrease?

Back 36

1. AV junctional rhythm, AV ectopic beats, AV re-entry tachycardia
2. WPW
3. LGL

Front 37

6. abnormal QRS morphology
what can cause pathological Q waves?

Back 37

= deeper than 2 squares, more than 1/4 the height of R wave, or more than 1 square wide
1. MI (necrosis)
2. LVH (septal hypertrophy)
3. BBB
4. pulmonary embolism (if in lead III)

Front 38

6. abnormal QRS morphology
what can cause the QRS to be too big?

Back 38

= less than 25mm high, bigger than S in V5 and V6, smaller tha S in V1 and V2
1. VH
2. posterior MI (tall R in V1)
3. WPW (tall R in V1)
4. dextrocardia
5. BBB (if wide as well)

Front 39

6. abnormal QRS
left ventricular hypertrophy

Back 39

1.
2.
3.
4.
5.
6. deep S in R sided leads and tall R in L sided leads
7. depression (strain)
8. inverted (strain)
9.
10. L deviation
causes?

Front 40

6. abnormal QRS
right ventricular hypertrophy

Back 40

1.
2.
3.
4.
5.
6. deep S in L sided leads and tall R in R sided leads
7. depression (strain)
8. inverted (strain)
9.
10. R deviation
causes? may occur with RBBB; pulmonary hypertension, pulmonary sclerosis

Front 41

6. abnormal QRS
WPW

Back 41

= bundle of Kent accessory pathway in the left side that bypasses AV node/bundle of his, to directly connect the atria and ventricles
1.
2.
3.
4.
5. shorter
6. tall R in R sided leads or deep S in L sided leads (depends on where is access. pathway - it's the opposite side)
7.
8.
9.
10. R deviation
causes?

Front 42

6. abnormal QRS morphology
what can cause the QRS to be too small?

Back 42

1. obesity
2. emphysema
3. pericadial effusion

Front 43

6. abnormal QRS morphology
what can cause the QRS to be too wide?

Back 43

= conduction through the ventricles is slower than usual, depolarization may take an abnormal route
1. BBB
2. ventricular rhythms
3. hyperkalemia

Front 44

6. abnormal QRS morphology
what can cause either RBBB or LBBB, and what's the clinical significance of each?

Back 44

1. ischemia
2. cardiomyopathy
3. atrial septal defect
4. massive pulmonary embolism
= very common in normal hearts, during SVT
1. ischemia
2. cardiomyopathy
3. LVH (from hypertension or aortic stenosis)
4. fibrosis of the conduction system
= more disastrous, with AMI or thrombolysis and renders the ECG unable to be analyzed further

Front 45

6. abnormal QRS morphology
what can cause the QRS to be abnormal?

Back 45

1. incomplete BBB
2. fascicular block (slurred or notched QRS)
3. WPW (additional delta wave along with short PRint)

Front 46

7. abnormal STseg
what can cause it be elevated?

Back 46

1. AMI (acute and subacute)
2. LV aneurysm
3. prinzmetal's angina
4. pericarditis
5. high take-off (normal variant)
6. aortic dissection

Front 47

what markers and clinical modifications should be present with myocardial infarctions?

Back 47

risk factors= smoking, hypertension, DM, hyperlipidemia, age, males, family history
measurable markers=
1. troponin I/T and CK-MB at 24h (troponin decreases until 6 days after; CK-MB decreases until 3rd day)
2. AST at 30h (decreases until 5 days after)
3. LDH at 48h (decreases until 6 days after)

Front 48

how can you localize myocardial infarctions within the left ventricle?

Back 48

= find the leads with STseg elevation or the mirror of it

1. anterior: V1-4
2. lateral: I, avL, V5-6
3. anterolat.: I, avL, V1-6
4. inferior: II, III, avF
*5. posterior: V1-4 depression

Front 49

7. abnormal STseg
what can cause its depression?

Back 49

1. ischemia (most common change)
2. posterior AMI
3. digoxin, quinidine
4. VH with strain

Front 50

what is digoxin and what are it's effects?

Back 50

= anti-arrhythmic drug
1. STseg depression "reverse tick" into negative T wave, especially if tall R
2. reduced T wave
3. QTint shortening

Front 51

8. abnormal T wave
what causes it to be too tall?

Back 51

1. hyperkalemia
2. AMI (also, hyperacute)
3. normal varient, best to compare readings at different times

Front 52

8. abnormal T wave
what causes it to be too small?

Back 52

1. hypokalemia
2. pericardial effusion
3. hypothyroidism

Front 53

8. abnormal T wave
what causes it to be inverted?

Back 53

1. ischemia
2. MI
3. VH with strain
4. digoxin
5. normal variant (avR, V1, V2 (kids), V3 (blacks))
6. with BBB
7. with pericarditis
non-diagnostic ecg appearance:
8. hyperventilation
9. mitral valve prolapse
10. pulmonary embolism
11. subarachnoid hemorrhage

Front 54

9. abnormal QTint
what can cause it to be shorter than .35s?

Back 54

1. hypercalcemia
2. digoxin
3. hyperthermia

Front 55

9. abnormal QTint
hypercalcemia

Back 55

1.
2.
3.
4.
5.
6.
7.
8. early ventricular repolarization; maybe prominent U wave
9. shortened
10.
causes? hyper PTH, malignancy, excessive vit.D, sarcoidosis, thyrotoxicosis

Front 56

9. abnormal QTint
what causes it to be longer than .43s?

Back 56

1. hypocalcemia
2. anti-arrhythmic drugs: quinidine, procainamide ** also seen with torsades de pointes
3. acute myocarditis
4. hereditary syndromes
* maybe: AMI, cerebral injury, hypertrophic cardiomyopathy, hypothermia

Front 57

8. abnormal T wave
when will a U wave be present?

Back 57

1. hypercalcemia
2. hypokalemia
3. hyperthyroidism
** is isn't diagnostic, instead, just a clue.

Front 58

8. abnormal T wave (with U wave)
hypokalemia

Back 58

1.
2.
3.
4.
5. 1st degree AV block
6.
7. depression
8. small T, with U
9.
10.
causes?