EKGs

Question 1

Overview of pathophys leading to arrhythmias

Answer 1

1. SA node dysfunction
2. Ectopic pacemaker (atrial, junctional, ventricular)
3. Re-entrant circuits (atrial or ventricular)
4. Blocks
5. Pre-excitation syndromes
   -escape rhythms: atrial (60-80 bpm), junctional (40-60bpm) and ventricular (20-40bpm)
   -normal HR=3-5 big boxes on EKG

Question 2

Premature beats

Answer 2

1. Premature patterns: bigeminy or trigeminy (can be atrial, junctional or ventricular)
2. PAC, PJC or PVC

Question 3

Normal sinus rhythm

Answer 3

1. Presence of P, QRS, and T waves
2. R-R interval and distance between waves consistent
3. Leads I, II and aVF upright, lead aVR opposite/down
4. P waves look same throughout (same morphology and direction)

Question 4

Sinus arrhythmia (not a true arrhythmia)

Answer 4

1. Unequal distance between identical waves/intervals but normal rate

Question 5

Sinus tachycardia

Answer 5

1. Rate is faster >100bpm (<3 big boxes)

Question 6

Sinus bradycardia

Answer 6

1. Rate is slower <60bpm (>5 big boxes)

Question 7

Sinus pause

Answer 7

1. There is an extended period of time between sinus beats and no other pacemaker foci takes over
2. Causes: meds/drugs, ischemia, damage to SA node
3. Concern arises when pause is longer than 3 seconds, multiple frequent pauses or pt is symptomatic

Question 8

Sick sinus syndrome

Answer 8

1. Variety of rhythms including sinus brady, tachy-brady, sinus arrest, etc
2. Often requires pacemaker

Question 9

Atrial escape rhythm

Answer 9

1. A spot in the atria takes over as pacemaker and P wave morphology changes, narrow QRS
2. Rate=60-80bpm

Question 10

Ectopic atrial tachycardia

Answer 10

1. Similar to atrial escape but at a faster rate, 100-150bpm (<3 big boxes)

Question 11

Wandering atrial pacer (multi-focal)

Answer 11

1. Multiple areas in the atria takeover as pacemaker
2. There are at least 3 different P wave morphologies within same lead
3. Caused by vagal nerve activity

Question 12

Multi-focal atrial tachycardia

Answer 12

1. Same as wandering atrial but at a faster rate >100bpm, P morphology changes

Question 13

AVNRT

Answer 13

1. Re-entrant circuit AV nodal origin
2. Normal QRS, but fast rate=150-250

Question 14

Afib (slow, normal, rapid)

Answer 14

1. Afib: multiple atria foci firing randomly, atria can’t contract normally
   -no P waves, “irregularly irregular”, wavy baseline
   RVR: fast Afib, needs treatment
   SVR: slow Afib

Question 15

Atrial flutter

Answer 15

1. Re-entrant tachycardic circuit where the AV node can’t keep up and ventricular rate is slower
2. Back-to-back flutter waves/”sawtooth” appearance
3. Rate around 300bpm
4. Distance between QRS may vary

Question 16

Junctional escape

Answer 16

1. Area near the AV node takes over as pacemaker
2. P waves can be absent, retrograde or inverted
3. Rate=40-60bpm

Question 17

Accelerated junctional

Answer 17

1. Faster junctional escape, >60bpm

Question 18

Idioventricular/ventricular escape

Answer 18

1. Area in the ventricle takes over as pacemaker
2. Wide QRS, no P waves
3. Rate=20-40bpm
   -signal returns to baseline between beats

Question 19

Accelerated ventricular escape

Answer 19

1. Ventricular escape but faster, >40bpm

Question 20

V-tach (monofocal)

Answer 20

1. Sudden onset of ventricular firing/depolarization
2. Wide QRS, rate=150-250bpm
3. Mono or polymorphic
4. Sustained vs non-sustained (>30 seconds) pulse vs pulseless
   -3 PVCs=V-tach

Question 21

Multi-focal V-tach/Torsades des pointes

Answer 21

1. Polymorphic V-tach
2. “Twisted ribbon” appearance
3. Typically occurs in those with QT prolongation with an R on T event (R wave occurs during repolarization), also with electrolyte abnormalities
4. Tx=magnesium

Question 22

Ventricular flutter

Answer 22

1. Type of V-tach but faster, rate=250-350
2. Ventricular waves of similar amplitude
3. Can quickly deteriorate into Vfib

Question 23

Ventricular fibrillation

Answer 23

1. Multiple foci firing simultaneously, rapid twitching/fibrillating of ventricles
2. Patients that present with this are in cardiac arrest and require immediate defibrillation
3. Rate=350+

Question 24

AV node block 1st degree

Answer 24

1. AV node slows conduction more than normal, long but consistent P-R intervals (>1 big box, 3-5 small boxes)

Question 25

2nd degree block

Answer 25

1. Mobitz type I/Wenckebach: PR interval progressively gets longer until a QRS complex gets dropped, then resets -some P waves without QRS complex 2. Mobitz type II: PR interval does not change, dropped QRS complex

Question 26

3rd degree block

Answer 26

1. No atrial impulses get through to ventricle 2. No relationship between P and QRS waves 3. Variable PR interval -draw intervals between P waves

Question 27

THE HEART BLOCK POEM

Answer 27

1. If R is far from P, then you have a first degree 2. Longer, longer, longer, drop! Then you have a Wenckebach 3. If some Ps don't get through, then you have a Mobitz II 4. If Ps and Qs don't agree, then you have a third degree

Question 28

Right BBB

Answer 28

1. Block occurs distal to AV bundle, affected ventricle will depolarize slightly after non-affected one 2. QRS>120ms 3. RSR' in V1-V3 (bunny ears) 4. Wide, slurred S wave in V5-V6 and I and aVL -BBB typically have QRS and T wave on opposite sides of isoelectric baseline

Question 29

Left BBB

Answer 29

1. QRS>120ms 2. Dominant S wave in V1 3. Broad monophasic R wave in V5-V6 and I and aVL 4. No Q waves in I, V5-V6

Question 30

Accessory pathway WPW

Answer 30

1. Short PR interval, presence of delta wave (curving of R wave) 2. Can cause a "short circuit" tachycardia and possibly sudden cardiac death

Question 31

Accessory pathway LGL

Answer 31

1. Short/absent PR interval, NO delta wave 2. Higher risk for AVNRT