Heart Blocks
Heart blocks are fun, and way easier than you think. Below, we will go over first degree, second degree (types I and II), and third degree heart blocks. Easy peasy.
First Degree Heart Block
Don't be scared. Take a deep breath.
First degree heart blocks means that the space between the p wave and the qrs is bigger than it should be.
THAT'S IT.
More technical details for those interested: the space between the p wave and the qrs is called the PR interval, which is supposed to be less than .20 seconds long. When they are longer than .20, this is known as a first degree heart block.
This heart block indicates that the electrical signal moves from the atria (p wave) to the ventricle (qrs) more slowly than it should. This could be due to age, previous MI, heart disease, or other problems.
Treatment: None, nobody cares
Second Degree Heart Block, Type I (Wenckebach)
Seriously, if you're still scared, you need to go get a massage or something. This is stupid easy.
The second degree heart block (type I) is nicknamed the Wenckebach. You just learned what the PR interval is, right? Check out this rhythm.
In a Wenckebach, the PR interval starts off normal, then gets longer on the next beat. On the next beat, it's even longer. Then, after the initial p wave, it drops and there is no qrs. Just a lonely p wave that didn't make it past the atria.
After that, the pattern starts over and begins again.
Remember the little rhyme that goes "Long, longer, longest, drop- now you have a Wenckebach!"
Treatment: Possibly medications, sometimes a pacemaker
Second Degree Heart Block Type II
This type of heart block is similar to the Wenckebach you just learned about, but with one key difference: there is no long, longer, longest and then a drop. There's only the drop!
I'm saying that sometimes you get a p wave that just doesn't follow through with the qrs. The heart will try another beat with another p wave, and hopefully trigger the qrs.
Electrically, the heart is having trouble conducting electricity from the atria (p wave) to the ventricle (qrs). This is a little more serious of a problem.
Treatment: pacemaker
Third Degree Heart Block
This is the big one. And it's the toughest to spot, I'm not going to lie. Practice makes perfect, and once you understand what's happening, it's a lot easier to look at.
In previous blocks, the atria and the ventricle have been having a harder and harder time of coordinating their efforts, right? Some signals weren't passed from the atria to the ventricle.
In a third degree block, there is NO communication between the atria and the ventricle. They can't talk to each other, so they just beat by themselves to their own drum rhythm, so to speak.
The rhythm looks confusing because some p waves are buried inside of qrs complexes or t waves. Just space them out with your fingers and you should be able to find them easily!
This heart block is incredibly dangerous and can quickly dissolve into vfib or vtach.
Treatment: ICU + transvenous pacing until the person gets a pacemaker, stat!