Question

What are the differences in the different types of AV blocks?

Answer 1

There are generally three types of AV blocks. They are first degree, second degree and third degree AV block. The AV blocks are that the signal transmission from the atria to ventricle is blocked and this affect the contraction of the heart.

The difference between these blocks are that in the first degree AV block it's not a true block and it just delays the impulse transmission. We can identify it by the increase in the PR interval for about 200msecond.

The second degree block can be again split into type I and type II. In type I it's a nodal block. It can be identified by the lengthen PR interval till the WRS wave falldown. So we can find fronthis that the P wave was not reaching the ventricles. In type II we can see a nonconducted p wave and a constant PR interval.

In third degree block a slow rythm can be seen as the P wave is not conducted to the ventricle. So the rate atria contracts is faster than ventricle contraction rate and we can see that the QRS complex gets narrowed due to that. So it's an infranodal block.