EKG preexcitation pt 2

Question 1

1) How do you map?
2) When is it indicated?
3) What do you do once you map it?

Answer 1

1) EPS studies
2) Indicated in patients with h/o syncope and tachyarrhythmias
3) Once ID, accessory pathway(s) may be ablated (sealed)

Question 2

Give the tl;dr of WPW

Answer 2

WPW increases risk of sudden cardiac death, but rare initial manifestation
Most patients can be “leisurely” evaluated and treated
Prognosis is excellent
Short PR without Delta wave = increased risk of tachyarrhythmias but exceedingly rare

Question 3

With WPW, short PR and delta wave typically only seen when in what?

Answer 3

a more normal rhythm and rate such as NSR

Question 4

What may work for WPW?

Answer 4

Blocking AV node – vagal maneuver or Rx may induce AVRT in susceptible patients

Question 5

What are the arrythmias assoc. with WPW?

Answer 5

AVRT – narrow QRS complexes (orthodromic) more common than wide QRS complexes (antidromic)
AF may be very fast (~300/min), may rarely lead to VF

Question 6

What are some DDXs for wide QRS complex tachycardias? Define each

Answer 6

1) V-Tach
2) Supraventricular tachycardia with aberrant conduction
-SVT with underlying BBB
-Usually rate dependent, seen with faster rates (critical rate)
3) AVRT – antidromic tachycardia, in patients with preexcitation WPW
4) Paced rhythm: Pacer senses the P wave, fires within ventricle to cause depolarization

Question 7

Accessory pathway in __________ alters vectors, so you assess axis or amplitude with caution (ventricular hypertrophy or BBB)

Answer 7

WPW

Question 8

Describe AVNRT

Answer 8

1) Abrupt onset (initiated by PAC or premature junctional contraction)
2) Regular rhythm – rate 150-200/min
3) Retrograde P waves may be seen
-Leads II or III
-Pseudo R’ in V1
4) QRS is usually narrow
5) NO delta waves
6) Carotid message or Adenosine may terminate

Question 9

Describe atrial flutter

Answer 9

1) Regular saw-toothed P waves
2) 2:1, 3:1, 4:1, etc. block
3) Atrial rate 250-300
4) Ventricular rate ½, 1/3, ¼ etc. of atrial rate
5) Narrow QRS
6) Carotid message increases block (slow ventricular rate but does not terminate)

Question 10

Describe afib

Answer 10

1) “irregular irregular pattern of QRS”
2) Atrial rate often > 300
3) Narrow QRS
4) Ventricular rate variable
5) Carotid message may slow ventricular rate a bit but not terminate

Question 11

Describe MAT (Multifocal Atrial Tachycardia)

Answer 11

1) Irregular rhythm
2) At least 3 different P wave morphologies
3) Rate 100-200, sometimes < 100
4) Carotid message has minimal effect on rate and does not terminate

Question 12

Describe PAT (Paroxysmal Atrial Tachycardia)

Answer 12

1) Regular rhythm
2) Rate 100-200
3) Characteristic warm up period in autonomic form
4) Carotid massage – minimal affect on rate, does not terminate

Question 13

Describe WPW AV reciprocating tachycardia

Answer 13

1) Narrow QRS complex (orthodromic) – 0.10 sec or less – more common
2) Wide QRS complex (antidromic) – more than 0.10 sec
3) Secondary to preexcitation – if WPW may see Delta Waves once rate slows in some leads
4) Vagal maneuvers or Adenosine may terminate if orthodromic
5) May precipitate in a patient with WPW