Heart block (theory 2)

Question 1

1st degree heart block

Answer 1

-every impulse is delayed slightly
-delay between atria depolarisation and ventricular depolarisation larger than normal
-PR interval more than 5 little boxes or 0.2 secs
-least serious of heart blocks
-first indication of damage to AV node

Question 2

Second degree heart block type 1

Answer 2

-impulse occasionally prevented from proceeding to ventricles
-increasing PR interval gradually until beat is dropped
-60-100bpm

Question 3

Second degree heart block type 2

Answer 3

-consistent PR interval
-rhythm is regular except for dropped beats

Question 4

Third degree heart block

Answer 4

-complete dissociation of AV node
-all impulses are blocked
-ventricles develop their own pacemaker
-generally bradycardic
-regular atrial rhythm
-P wave without QRS complex
-Ventricular rhythm is regular