Arrhythmias

Question 1

Third Degree AV Block

Answer 1

• Complete failure of AV node conduction, subsequent dissociation
• SA nodal fun, atrial conduction pathways, atrial depolarization normal
• wave of depol not conduction through to ventricles

Question 2

Cause of Third Degree AV block

Answer 2

Idiopathic (most common)

Question 3

ECG Characteristics - Third Degree AV Block

Answer 3

• Normal P wave
• Regular P-P interval at normal sinus rate
• No supra ventricular input –> ventricules depol bc of ventricular automaticity (30-50bpm K9, 60-80bpm Fl)
• Superimposed ventricular rhythm with wide QRS ventricular escape that has no Assoc to P waves with reg R-R interval

Question 4

What happens if ventricular escape rhythm during 3rd degree block treated with lidocaine?

Answer 4

May suppress escape rhythm –> lead to cardiac arrest