EKG Cards

Question 1

Identify this EKG.

Answer 1

Left Anterior Fascicular Block
* Slightly prolonged QRS duration (Not quite 120 msec or < 3 small boxes)
* Left axis deviation
* qR complex in leads I and aVL (Depolarization going towards these leads)
* rS complex in leads II, III, and aVF (Depolarization going away from these leads)

Question 2

Identify this EKG.

Answer 2

Left Anterior Fascicular Block

ECG Criteria
* Left axis deviation (usually -45 to -90 degrees)
* qR complexes in leads I, aVL
* rS complexes in leads II, III, aVF
* Prolonged R wave peak time in aVL > 45ms

In LAFB, the QRS voltage in lead aVL may meet voltage criteria for LVH (R wave height > 11 mm), but there will be no LV strain pattern.

Question 3

Identify this EKG.

Answer 3

Left Anterior Fascicular Block

ECG Criteria
* Left axis deviation (usually -45 to -90 degrees)
* qR complexes in leads I, aVL
* rS complexes in leads II, III, aVF
* Prolonged R wave peak time in aVL > 45ms

In LAFB, the QRS voltage in lead aVL may meet voltage criteria for LVH (R wave height > 11 mm), but there will be no LV strain pattern.

Question 4

Identify this EKG.

Answer 4

Bifascicular block (RBBB w/ LAFB)
Clinically, bifascicular block presents with one of two ECG patterns:

• Right bundle branch block (RBBB) with left anterior fascicular block (LAFB), manifested as left axis deviation (LAD)
• RBBB and left posterior fascicular block (LPFB), manifested as right axis deviation (RAD) in the absence of other causes

Question 5

Identify this EKG.

Answer 5

Bifascicular Block (RBBB w/ LPFB and RAD)

Clinically, bifascicular block presents with one of two ECG patterns:

• Right bundle branch block (RBBB) with left anterior fascicular block (LAFB), manifested as left axis deviation (LAD)
• RBBB and left posterior fascicular block (LPFB), manifested as right axis deviation (RAD) in the absence of other causes

Question 6

Identify this EKG.

Answer 6

Bifascicular Block (RBBB w/ LPFB and RAD)

Clinically, bifascicular block presents with one of two ECG patterns:

• Right bundle branch block (RBBB) with left anterior fascicular block (LAFB), manifested as left axis deviation (LAD)
• RBBB and left posterior fascicular block (LPFB), manifested as right axis deviation (RAD) in the absence of other causes

EKG:
* RBBB with wide QRS, slurred S wave in lead I and slurred R in V1.
* Right axis deviation (dominant negative deflection in leads I and aVl) with dominant positive deflection in aVf along with rS pattern in lead I and qR pattern leads III and aVf, suggesting left posterior fascicular block.

Question 7

Identify this EKG.

Answer 7

Bifascicular block (RBBB w/ LAFB)
Clinically, bifascicular block presents with one of two ECG patterns:

• Right bundle branch block (RBBB) with left anterior fascicular block (LAFB), manifested as left axis deviation (LAD)
• RBBB and left posterior fascicular block (LPFB), manifested as right axis deviation (RAD) in the absence of other causes

Question 8

Identify this EKG.

Answer 8

Right Bundle Branch Block
* QRS duration > 120ms
* RSR’ pattern in V1-3 (“M-shaped” QRS complex)
* Wide, slurred S wave in lateral leads (I, aVL, V5-6)

Question 9

Identify this EKG.

Answer 9

Right Bundle Branch Block
* QRS duration > 120ms
* RSR’ pattern in V1-3 (“M-shaped” QRS complex)
* Wide, slurred S wave in lateral leads (I, aVL, V5-6)

Question 10

Identify this EKG.

Answer 10

Left Bundle Branch Block (INCOMPLETE)
* QRS duration ≥ 120ms (QRS duration <120 ms is considered INCOMPLETE LBBB)
* Dominant S wave in V1
* Broad monophasic R wave in lateral leads (I, aVL, V5-6)
* Absence of Q waves in lateral leads
* Prolonged R wave peak time > 60ms in leads V5-6
* Note: Incomplete LBBB is diagnosed when typical LBBB morphology is associated with a QRS duration < 120 ms.

Question 11

Identify this EKG.

Answer 11

Left Bundle Branch Block (COMPLETE)
* QRS duration ≥ 120ms
* Dominant S wave in V1
* Broad monophasic R wave in lateral leads (I, aVL, V5-6)
* Absence of Q waves in lateral leads
* Prolonged R wave peak time > 60ms in leads V5-6
* Note: Incomplete LBBB is diagnosed when typical LBBB morphology is associated with a QRS duration < 120 ms.

Question 12

Identify this EKG.

Answer 12

True trifascicular block refers to the presence of conduction delay in all three fascicles below the AV node (RBBB, LAFB, LPFB), manifesting as bifascicular block and 3rd degree AV block. One of two ECG patterns is present:

3rd degree AV block + RBBB + LAFB or;
3rd degree AV block + RBBB + LPFB

Other rare indicators of trifascicular block include:

Normal sinus rhythm with alternating LBBB/RBBB
RBBB with alternating fascicular blocks on a beat-to-beat basis
These herald impending failure of all three fascicles and associated 3rd degree AV block

Question 13

Identify this EKG.

Answer 13

ECG Features: PR interval > 200 milliseconds (five small squares)

Question 14

Identify this EKG.

Answer 14

Sinus Bradycardia w/ 1st degree AV Block (note that PR Interval is >300 ms)

Question 15

Identify this EKG.

Answer 15

AV Block: 2nd Degree, Mobitz I (Wenckebach Phenomenon)

Progressive prolongation of the PR interval culminating in a non-conducted P wave:

PR interval is longest immediately before dropped beat
PR interval is shortest immediately after dropped beat

Question 16

Identify this EKG.

Answer 16

2nd Degree AV Block with 2:1 conduction

Question 17

Identify this EKG.

Answer 17

2nd degree AV Block with 2:1 conduction

Question 18

Identify this EKG.

Answer 18

Brugada Type III
* Brugada type 3: can be the morphology of either type 1 or type 2, but with <2mm of ST segment elevation.

Question 19

Identify this EKG.

Answer 19

Brugada Type II

Question 20

Identify this EKG.

Answer 20

Lown-Ganong-Levine Syndrome
* Proposed pre-excitation syndrome.
* Accessory pathway composed of James fibres.

Characteristic ECG findings of: short PR interval (<120ms);
* normal P wave axis
* normal/narrow QRS morphology in the presence of paroxysmal tachyarrhythmia.

Question 21

Identify this EKG.

Answer 21

Wolff-Parkinson White (WPW Type A)

ECG Features:
* PR interval < 120ms
* Delta wave: slurring slow rise of initial portion of the QRS
* QRS prolongation > 110ms
* Discordant ST-segment and T-wave changes (i.e. in the opposite direction to the major component of the QRS complex)
* Pseudo-infarction pattern in up to 70% of patients — due to negatively deflected delta waves in inferior/anterior leads (“pseudo-Q waves”), or prominent R waves in V1-3 (mimicking posterior infarction)

(Type A) Left-sided AP: produces a positive delta wave in all precordial leads, with R/S > 1 in V1. Sometimes referred to as a type A WPW pattern
(Type B) Right-sided AP: produces a negative delta wave in leads V1 and V2. Sometimes referred to as a type B WPW pattern

Question 22

Identify this EKG.

Answer 22

Wolff-Parkinson White (WPW Type A)

ECG Features:
* PR interval < 120ms
* Delta wave: slurring slow rise of initial portion of the QRS
* QRS prolongation > 110ms
* Discordant ST-segment and T-wave changes (i.e. in the opposite direction to the major component of the QRS complex)
* Pseudo-infarction pattern in up to 70% of patients — due to negatively deflected delta waves in inferior/anterior leads (“pseudo-Q waves”), or prominent R waves in V1-3 (mimicking posterior infarction)

(Type A) Left-sided AP: produces a positive delta wave in all precordial leads, with R/S > 1 in V1. Sometimes referred to as a type A WPW pattern
(Type B) Right-sided AP: produces a negative delta wave in leads V1 and V2. Sometimes referred to as a type B WPW pattern

Question 23

Identify this EKG.

Answer 23

Wolff-Parkinson-White (Type A Pattern)

ECG Features:
* PR interval < 120ms
* Delta wave: slurring slow rise of initial portion of the QRS
* QRS prolongation > 110ms
* Discordant ST-segment and T-wave changes (i.e. in the opposite direction to the major component of the QRS complex)
* Pseudo-infarction pattern in up to 70% of patients — due to negatively deflected delta waves in inferior/anterior leads (“pseudo-Q waves”), or prominent R waves in V1-3 (mimicking posterior infarction)

(Type A) Left-sided AP: produces a positive delta wave in all precordial leads, with R/S > 1 in V1. Sometimes referred to as a type A WPW pattern
(Type B) Right-sided AP: produces a negative delta wave in leads V1 and V2. Sometimes referred to as a type B WPW pattern

Question 24

Identify this EKG.

Answer 24

Premature Atrial Complex
* Abnormal (non-sinus) P wave usually followed by a normal QRS complex (< 120 ms)
* Post-extrasystolic pauses may be present — PACs that reach the SA node may depolarise it, causing the SA node to be “reset”, with a longer-than-normal interval before the next sinus beat arrives
* PACs may also be conducted aberrantly (usually RBBB morphology), or not conducted at all. P waves will still be visible in both cases

Question 25

Identify the unique feature on this EKG.

Answer 25

* Osborn Wave (J Wave): positive deflection seen at the J point in precordial and true limb leads. It is most commonly associated with hypothermia. These changes will appear as a reciprocal, negative deflection in aVR and V1.

Question 26

Identify this EKG.

Answer 26

**Pericarditis** * Widespread concave ST elevation and PR depression throughout most of the limb leads (I, II, III, aVL, aVF) and precordial leads (V2-6) * Reciprocal ST depression and PR elevation in lead aVR (± V1) * Sinus tachycardia is also common in acute pericarditis due to pain and/or pericardial effusion Pericarditis can be difficult to differentiate from Benign Early Repolarisation (BER) as both conditions are associated with concave ST elevation. One useful trick to distinguish between these two entities is to look at the ST segment / T wave ratio and the Fish Hook Pattern ST segment / T wave ratio: The vertical height of the ST segment elevation (from the end of the PR segment to the J point) is measured and compared to the amplitude of the T wave in V6. A ratio of > 0.25 suggests pericarditis A ratio of < 0.25 suggests BER

Question 27

Identify this EKG.

Answer 27

**Pericarditis** * Widespread concave ST elevation and PR depression throughout most of the limb leads (I, II, III, aVL, aVF) and precordial leads (V2-6) * Reciprocal ST depression and PR elevation in lead aVR (± V1) * Sinus tachycardia is also common in acute pericarditis due to pain and/or pericardial effusion Pericarditis can be difficult to differentiate from Benign Early Repolarisation (BER) as both conditions are associated with concave ST elevation. One useful trick to distinguish between these two entities is to look at the ST segment / T wave ratio and the Fish Hook Pattern ST segment / T wave ratio: The vertical height of the ST segment elevation (from the end of the PR segment to the J point) is measured and compared to the amplitude of the T wave in V6. A ratio of > 0.25 suggests pericarditis A ratio of < 0.25 suggests BER * Spodick Sign: Downsloping TP segment seen as an early ECG manifestation in ~30% of patients with pericarditis, best visualised in leads II and the lateral precordial leads * PR depression alone can be a masquerader as it is seen in 12% of patients with STEMI

Question 28

Identify this EKG.

Answer 28

Bidirectional Ventricular Tachycardia Bidirectional ventricular tachycardia (BVT) is a rare ventricular dysrhythmia characterised by a beat-to-beat alternation of the frontal QRS axis. It is most commonly associated with severe digoxin toxicity

Question 29

Identify this EKG.

Answer 29

Bidirectional Ventricular Tachycardia Bidirectional ventricular tachycardia (BVT) is a rare ventricular dysrhythmia characterised by a beat-to-beat alternation of the frontal QRS axis. It is most commonly associated with severe digoxin toxicity

Question 30

Identify the most likely underlying etiology.

Answer 30

Massive Pericardial Effusion/Pericardial Tamponade Massive pericardial effusion produces a characteristic ECG triad of: * Low QRS voltage * Tachycardia * Electrical alternans - occurs when the heart swings backwards and forwards within a lartge fluid-filled pericardium.

Question 31

Identify the most likely underlying etiology.

Answer 31

**Massive Pericardial Effusion/Pericardial Tamponade** Massive pericardial effusion produces a characteristic ECG triad of: * Low QRS voltage * Tachycardia * Electrical alternans

Question 32

Identify the EKG phenomenon.

Answer 32

**Electrical Alternans**, associated with massive pericardial effusion/pericardial tamponade.

Question 34

Identify this EKG Strip.

Answer 34

**Normal Sinus Rhythm** * Regular rhythm at a rate of 60-100 bpm (or age-appropriate rate in children) * Each QRS complex is preceded by a normal P wave * Normal P wave axis: P waves upright in leads I and II, inverted in aVR * The PR interval remains constant * QRS complexes < 100 ms wide (unless co-existent interventricular conduction delay present) Normal heart rates in children Newborn: 110 – 150 bpm 2 years: 85 – 125 bpm 4 years: 75 – 115 bpm 6 years+: 60 – 100 bpm

Question 35

Identify this EKG strip.

Answer 35

**Normal Sinus Rhythm** * Regular rhythm at a rate of 60-100 bpm (or age-appropriate rate in children) * Each QRS complex is preceded by a normal P wave * Normal P wave axis: P waves upright in leads I and II, inverted in aVR * The PR interval remains constant * QRS complexes < 100 ms wide (unless co-existent interventricular conduction delay present) Normal heart rates in children Newborn: 110 – 150 bpm 2 years: 85 – 125 bpm 4 years: 75 – 115 bpm 6 years+: 60 – 100 bpm

Question 36

Identify this EKG.

Answer 36

**Normal Sinus Rhythm** * Regular rhythm at a rate of 60-100 bpm (or age-appropriate rate in children) * Each QRS complex is preceded by a normal P wave * Normal P wave axis: P waves upright in leads I and II, inverted in aVR * The PR interval remains constant * QRS complexes < 100 ms wide (unless co-existent interventricular conduction delay present) Normal heart rates in children Newborn: 110 – 150 bpm 2 years: 85 – 125 bpm 4 years: 75 – 115 bpm 6 years+: 60 – 100 bpm