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Cardiology > EKG Differentials > Flashcards

EKG Differentials Flashcards

1
Q

Lead I

Inverted P wave

A

• Ectopic atrial premature beat or rhythm
• AV junctional/ventricular premature complex or
rhythm with retrograde atrial activation
• Dextrocardia: Inverted P-QRS-T in leads I and aVL with reverse R wave progression in the precordial leads
• Reversal of right and left arm leads: Inverted PQRS-T in leads I and aVL with normal R wave progression in the precordial leads

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2
Q

Lead II

Tall peaked P wave

A
  • Right atrial abnormality/enlargement

* Bi-atrial abnormality

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3
Q

Lead II

Bifid P wave with peak-to-peak interval > 0.03 sec. and P wave duration > 0.12 sec.

A

• Left atrial abnormality/enlargement

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4
Q

Lead II

Inverted P wave

A

• Ectopic atrial premature beat or rhythm
• AV junctional/ventricular premature complex or
rhythm with retrograde atrial activation

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5
Q

Lead II

Sawtooth regular P waves

A
  • Atrial flutter

* Artifact due to tremor (e.g., Parkinson’s disease, shivering)

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6
Q

Lead II

Irregularly irregular baseline

A
  • Atrial fibrillation
  • Artifact due to tremor
  • Multifocal atrial tachycardia
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7
Q

Lead II

Multiple P wave morphologies

A
  • Wandering atrial pacemaker (rate < 100 bpm)
  • Multifocal atrial tachycardia (rate > 100 bpm)
  • Sinus or atrial rhythm with multiple atrial premature complexes
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8
Q

Lead V1

Tall upright P wave

A

• Right atrial abnormality/enlargement

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9
Q

Lead V1

Deep inverted P waves

A

• Left atrial abnormality/enlargement

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10
Q

Lead V1

Dome and dart P wave

A

• Ectopic atrial rhythm

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11
Q

No P Waves

P Waves present but hidden

A
  • Ectopic atrial rhythm or APCs (P waves hidden in preceding T wave)
  • Junctional rhythm or SVT (P wave buried in QRS)
  • Supraventricular rhythm with marked first-degree AV block (P wave hidden in preceding T wave)
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12
Q

No P Waves

P Waves not present

A
  • Sinoventricular conduction due to hyperkalemia
  • Marked sinoatrial exit block or sinus bradycardia with junctional or ventricular rhythm (escape or accelerated)
  • Sinus pause or arrest
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13
Q

PR Interval

Prolonged (> 0.20 seconds) PR interval

A

• First-degree AV block
• Complete heart block: PR interval varies, has no
constant relationship to the QRS, and may intermittently exceed 0.20 seconds
• Supraventricular or junctional rhythm with retrograde atrial activation: P wave inverted in lead II
• Atrial premature complex

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14
Q

PR Interval

Short (< 0.12 seconds) PR interval

A

• Short PR with sinus rhythm and normal QRS
• Wolff-Parkinson-White pattern: Delta wave, wide
QRS, ST-T changes in a direction opposite to main deflection of QRS
• Low ectopic atrial rhythm: PR interval usually > 0.11 seconds; P wave inverted in lead II
• Ectopic junctional beat or rhythm with retrograde atrial activation: PR interval usually < 0.11 seconds; P wave inverted in lead II

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15
Q

PR Segment Depression

A
  • Normals: < 0.8 mm
  • Pericarditis
  • Pseudodepression due to atrial flutter or Parkinson’s tremor
  • Atrial infarction: Reciprocal elevation in opposite leads; inferior MI usually evident
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16
Q

PR Segment Elevation

3

A

1 Normals: < 0.5 mm
2 Pericarditis: Lead aVR only
3 Atrial infarction: Reciprocal depression in opposite leads

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17
Q

Increased QRS duration 0.10 to < 0.12 seconds

11

A 
1 Left anterior fascicular block 
2 Left posterior fascicular block
3 Incomplete LBBB 
4 Incomplete RBBB
5 Nonspecific IVCD 
6 LVH 
7 RVH 
8 Supraventricular beat or rhythm with aberrant intraventricular conduction 
9 Fusion beats
10 Wolff-Parkinson-White pattern
11 VPCs originating near the bundle of His (i.e., high in the interventricular septum)
18
Q

Increased QRS duration > 0.12 seconds

9

A 
1 RBBB
2 LBBB 
3 Supraventricular beat or rhythm with aberrant intraventricular conduction
4 Fusion beats
5 Wolff-Parkinson-White pattern 
6 Ventricular premature complexes 
7 Ventricular rhythm 
8 Nonspecific IVCD 
9 Paced beat
19
Q

Low voltage QRS

7

A 
1 Chronic lung disease 
2 Pericardial effusion 
3 Myxedema 
4 Obesity
5 Pleural effusion
6 Restrictive or infiltrative cardiomyopathy
7 Diffuse coronary artery disease
20
Q

Tall QRS

5

A 
1 LVH 
2 Hypertrophic cardiomyopathy
3 LBBB 
4 Wolff-Parkinson White pattern 
5 Normal persons with thin body habitus
21
Q

Prominent R wave in lead V1

7

A

1 RVH
2 Posterior wall MI
3 Incorrect lead placement: Electrode for lead V1 placed in 3rd instead of 4th intercostal space
4 Skeletal deformities (e.g., pectus excavatum)
5 RBBB
6 Wolff-Parkinson-White pattern
7 Duchenne’s muscular dystrophy

22
Q

Left axis deviation

A
  • Left anterior fascicular block (if axis > -45°, item 45)
  • Inferior wall MI (items 57, 58)
  • LBBB (item 47)
  • LVH (item 40)
  • Ostium primum ASD (item 79)
  • Chronic lung disease (item 81)
  • Hyperkalemia (item 74)
23
Q

Right axis deviation

A
  • RVH (item 41)
  • Vertical heart
  • Chronic lung disease (item 81)
  • Pulmonary embolus (item 82)
  • Left posterior fascicular block (item 46)
  • Lateral wall MI (items 55, 56)
  • Dextrocardia (item 80)
  • Lead reversal (item 03)
  • Ostium secundum ASD (item 78)
24
Q

Q wave myocardial infarction

A

(see items 51-60)
• Anterolateral MI: Abnormal Q waves in leads V4-V6
• Anterior MI: Abnormal Q waves in at least two consecutive
leads in V2-V4
• Anteroseptal MI: Abnormal Q waves in leads V1-V3 (and
sometimes V4)
• Lateral MI: Abnormal Q waves in leads I and aVL
• Inferior MI: Abnormal Q waves in at least two of leads II, III,
and aVF

25
Q

Pseudoinfarcts (Q waves in absence of MI)

A

• Wolff-Parkinson-White (item 34): Negative delta waves
mimic Q waves
• Hypertrophic cardiomyopathy (item 85): Q waves in I, aVL,
V4-V6 due to septal hypertrophy
• LVH (item 40): Poor R wave progression, at times with ST
elevation in V1-V3, can mimic anteroseptal MI. Inferior Q
waves may be present and can mimic inferior MI
• LBBB (item 47): QS pattern in V1-V4mimics anteroseptal MI.
Less commonly, Q waves in III and aVF mimic inferior MI
• RVH (item 41)
• Left anterior fascicular block (item 46)
• Chronic lung disease (item 81): Q waves appear in inferior
and/or right and mid-precordial leads
• Amyloid, sarcoid, and other infiltrative cardiomyopathic
diseases: Electrically active tissue replaced by inert substance
• Cardiomyopathy
• Chest deformity (e.g., pectus excavatum)
• Pulmonary embolism (item 82): Q wave in lead III and
sometimes aVF, but Q waves in II are rare
• Myocarditis
• Myocardial tumors
• Hyperkalemia (item 74)
• Pneumothorax: QS complex in right precordial leads
• Pancreatitis
• Lead reversal (item 03)
• Corrected transposition
• Muscular dystrophy
• Mitral valve prolapse: Rare Q wave in III and aVF
• Myocardial contusion: Q waves in areas of intramyocardial
hemorrhage and edema
• Left/right atrial enlargement: Prominent atrial repolarization
wave (Ta) can depress the PR segment and mimic Q waves
• Atrial flutter (item 18): Flutter waves may deform the PR
segment and simulate Q waves
• Dextrocardia (item 80)

26
Q

Early R wave progression (tall R wave in V1, V2; R/S > 1)

A
  • RVH (item 41)
  • Posterior MI (items 59, 60)
  • RBBB (item 43)
  • Wolff-Parkinson-White pattern (item 34)
  • Normals
  • Duchenne’s muscular dystrophy
27
Q

Poor R wave progression (first precordial lead where R

wave amplitude

A
  • Normals (abnormal lead placement)
  • Anterior or anteroseptal MI (items 53, 54)
  • Dilated or hypertrophic cardiomyopathy
  • LVH (item 40)
  • Chronic lung disease (item 81)
  • Cor pulmonale (item 82)
  • RVH (item 41)
  • Left anterior fascicular block (item 45)
28
Q

Reverse R wave progression (decreasing R wave

amplitude across precordial leads)

A
  • Anterior MI (items 53, 54)

* Dextrocardia (item 80)

29
Q

Initial slurring of R wave (delta wave)

A

• Wolff-Parkinson-White pattern (item 34)

30
Q

Terminal notching (of R or S wave)

A

• Hypothermia (Osborne wave; item 88)
• Early repolarization (item 61)
• Pacemaker spike (failure to sense; item 94)
• Atrial flutter (item 18): Flutter waves may be superimposed on
QRS

31
Q

ST segment elevation

A

• Myocardial injury (item 65): Convex upward ST elevation
localized to a few leads and terminates with an inverted T
(unless hyperacute peaked T wave). Reciprocal ST depression
evident in other leads. Q waves frequently present. ST & T
wave changes evolve, and T wave becomes inverted before ST
segment returns to baseline
• Acute pericarditis (item 84): Widespread ST elevation (I-III,
aVF, V3-V6) without reciprocal ST depression in other leads
except aVR. No Q wave. PR segment depression is
sometimes present. ST-T wave changes evolve; T wave often
becomes inverted after ST segment returns to baseline. Note:
Pericarditis (and ST elevation) may be focal
• Ventricular aneurysm: ST elevation usually with deep Q wave
or QS in same leads; ST & T wave changes persist and are
stable over a long period of time
• Early repolarization (item 61): Concave upward ST elevation
that ends with an upward T wave, with notching on the
downstroke of the R wave. T waves are usually large and
symmetrical. ST-T wave changes are stable over a long time
period
• LVH (item 40)
• Bundle branch block (items 43, 47)
• Central nervous system disease (item 86)
• Apical hypertrophic cardiomyopathy (item 85)
• Hyperkalemia (item 74)
• Acute cor pulmonale (item 82)
• Myocarditis
• Myocardial tumor

32
Q

ST segment depression

A

• Myocardial ischemia (item 64): horizontal or downsloping
• Repolarization changes secondary to ventricular hypertrophy
(item 67) or bundle branch block (items 43, 47)
• Digitalis effect (item 70)
• “Pseudodepression” due to superimposition of atrial flutter
waves or prominent atrial repolarization wave (as seen with
atrial enlargement, pericarditis, atrial infarction) on the ST
segment
• Central nervous system disorder (item 86)
• Hypokalemia (item 75)
• Antiarrhythmic drug effect (item 72)
• Mitral valve prolapse

33
Q

Nonspecific ST segment changes

A
  • Organic heart disease
  • Drugs (e.g., quinidine)
  • Electrolyte disorders (e.g., hypokalemia, item 75)
  • Hyperventilation
  • Myxedema (item 87)
  • Stress
  • Pancreatitis
  • Pericarditis (item 84)
  • Central nervous system disorders (item 86)
  • LVH (item 40)
  • RVH (item 41)
  • Bundle branch block (items 43, 44, 47, 48)
  • Healthy adults (normal variant) (item 02)
34
Q

Tall peaked T waves

A

• Hyperacute MI
• Angina pectoris
• Normal variant (item 02): Usually effects mid-precordial leads
• Hyperkalemia (item 74): More common when the rise in
serum potassium is acute
• Intracranial bleeding (item 86)
• LVH (item 40)
• RVH (item 41)
• LBBB (item 47)
• Superimposed P wave from APC, sinus rhythm with marked
first-degree AV block, complete heart block, etc.
• Anemia

35
Q

Deeply inverted T waves

A
  • Myocardial ischemia (item 64)
  • LVH (items 40, 67)
  • RVH (items 41, 67)
  • Central nervous system disorder (item 86)
  • Wolff-Parkinson-White pattern (item 34)
36
Q

Nonspecific T waves

A

• Persistent juvenile pattern: T wave inversion in V1-V3 in young
adults
• Organic heart disease
• Drugs (e.g., quinidine)
• Electrolyte disorders (e.g., hypokalemia, item 75)
• Hyperventilation
• Myxedema (item 87)
• Stress
• Pancreatitis
• Pericarditis (item 84)
• Central nervous system disorders (item 86)
• LVH (item 40)
• RVH (item 41)
• Bundle branch block (items 43, 44, 47, 48)
• Healthy adults (normal variant) (item 02)

37
Q

Long QT interval – Acquired conditions

A 
• Drugs (quinidine, procainamide, disopyramide, amiodarone,
sotalol, dofetilide, azimilide, phenothiazines, tricyclics,
lithium)
• Hypomagnesemia
• Hypocalcemia (item 77)
• Marked bradyarrhythmias
• Intracranial hemorrhage (item 86)
• Myocarditis
• Mitral valve prolapse
• Myxedema (item 87)
• Hypothermia (item 88)
• Liquid protein diets
38
Q

Long QT interval – Congenital disorders

A
  • Romano-Ward syndrome (normal hearing)

* Jervell and Lange-Nielson syndrome (deafness)

39
Q

Short QT interval

A
  • Hypercalcemia (item 76)
  • Hyperkalemia (item 74)
  • Digitalis effect (item 70)
  • Acidosis
  • Vagal stimulation
  • Hyperthyroidism
  • Hyperthermia
40
Q

Prominent U wave

A
  • Hypokalemia (item 75)
  • Bradyarrhythmias
  • Hypothermia (item 88)
  • LVH (item 40)
  • Coronary artery disease
  • Drugs (digitalis, quinidine, amiodarone, isoproterenol)
41
Q

Inverted U wave

A
  • LVH (item 40)
  • Severe RVH (item 41)
  • Myocardial ischemia
42
Q

Right axis deviation is associated with which conditions?

A
  • Chronic lung disease (e.g. emphysema)
  • RVH
  • Lateral wall MI
  • Dextrocardia
  • Vertical heart
  • PE
  • Ostium secundum ASD
  • Left posterior fascicular block

Cardiology (12 decks)

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