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Sem. B - ECG > Blocks > Flashcards

Flashcards in Blocks Deck (8)
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1

1st Degree Heart Block

1st Degree Heart Block

  • PR interval > 0.20secs (5 small squares)
  • Usually regular
  • Usually benign
  • No specific treatment required

 

2

2nd Degree Heart Block Mobitz 1 (Wenckebach)

2nd Degree Heart Block Mobitz 1 (Wenckebach)

  • PR interval extends until a P wave is not followed by a corresponding QRS complex
  • Following PR interval is short/normal and the cycle starts again
  • QRS complex must be seen at least twice in a row in order to see this pattern
  • Usually benign, asymptomatic pt do not require treatment, permanent pacing rarely required
  • Symptomatic pt usually respond to atropine

3

2nd Degree Heart Block Mobitz 2

2nd Degree Heart Block Mobitz 2

  • Intermittently P waves are not followed by a QRS, with no real pattern
  • P waves remain at a constant rate
  • Whenever there is a QRS, the PR interval remains constant throughout
  • Type 2 is of greater concern than Type 1 and sometimes requires pacing
  • Extended RR interval will be an exact multiple of the number of dropped beats
  • Likely to progress into bradycardia or 3rd degree block, can cause syncope and sudden cardiac death
  • Immediate admission for cardiac monitoring and likely permanent pacing

4

3rd Degree/Complete Heart Block

3rd Degree/Complete Heart Block

  • No relationship between the P waves and the QRS complexes
  • Usually more P waves than QRS complexes
  • P & QRS are both regular but independantly of each other
  • Ventricular response is usually bradycardic and the QRS are often wide and bizarre
  • Typically pt will present as severe bradycardia with independant atrial/ventricular rates
  • P likely to suffer ventricular standstill causing syncope or sudden cardiac death
  • Urgent admission for cardiac monitoring, usually permanent pacing

5

Left Bundle Branch Block (LBBB)

Left Bundle Branch Block (LBBB)

  • Wide QRS with possible absence of Q in lateral leads
  • Tall R waves Lateral I, V5-V6
  • Deep S waves anterior V1-V3
  • Broad 'notched' or 'M' shaped R wave in lateral leads

 

Traditionally LBBB accompanied by chest pain was criteria for thrombolysis

6

Right Bundle Branch Block (RBBB)

Right Bundle Branch Block (RBBB)

  • Broad QRS > 120 ms
  • RSR’ pattern in the anterior leads V1-3 (‘M-shaped’ QRS complex)
  • Wide, slurred S wave in the lateral leads (I, aVL, V5-6)

7

Bifascicular Block

Bifascicular Block

RBBB

+

Left Axis Deviation

8

Trifascicular Block

Trifascicular Block

RBBB

+

Left Axis Deviation

+

1st Degree Heart Block

 

May progress to 3rd degree/complete heart block then require permanent pacing