What is High Grade AV Block?

Okay, this is an entirely stupid question considering it's been 18 months since my diagnosis. After reading ElectricFranks question about upper PM limits and then Ronaldo's response, I have to ask what is High Grade AV Block? This is what I was dx'd with and have a PM, but only understand it at a kindergarten level (from the cardiologist). Can anyone tell me more - where does the electrical current go/not go? Is the problem in my atrium or ventricle or both? Left or right side? What else should I know - it's tough to know what you don't know! :)
Thanks so much,
Tracie

6 Comments

p.s.

by Tracey_E - 2009-12-30 07:12:19

nice name :o)

av blocks

by Tracey_E - 2009-12-30 07:12:26

I'm not sure what they mean by high grade, but I have a complete, or 3rd degree block. I was diagnosed when I was 5. The dr described it to me then as the top and bottom of my heart don't talk to each other. Pretty much sums it up!

The atria are the brains, they read the level of oxygen in our blood and raise/lower our hr as needed. The ventricles are the brawn, they produce the strong beat we feel as our pulse, which circulates the blood through our bodies. The SA node is in the atria, think of it as the control center. Ours works just fine. The SA node is nature's pacemaker and it sets the pace by telling the AV node in the ventricles when to beat. With a block, this signal either always or sometimes does not get through.

Complete, or third degree, means the signal never or almost never gets through. Those of us with this pace close to 100% off the time in the ventricle, almost never in the atria. Our natural pacemakers work just fine, but the circuit is broken and the signal does not get through.

A bit better than that is second degree block, which means either intermittent 3rd degree block or some of the beats get through all the time but not all. For example, a 2:1 block means for every 2 atrial beats, the ventricle will get the message once.

First degree block means sometimes some of the signals don't get through. First degree is usually left untreated unless there are symptoms.

I suspect high grade means third degree or complete. It doesn't really matter which one we have, the cure is the same for all of them. The pacemaker keeps an eye on things. Every time the atria beats, it gives the ventricles a chance to beat also. When it doesn't, the pm generates a signal to tell the ventricle to beat. The pm also watches our atria to make sure it doesn't skip or drop too low, but most of the time we don't pace much atrial.

Thank you

by Tracie - 2009-12-30 08:12:02

TraceyE (Yes, nice name!),
Thank you for this info. This is more than I got when dx'd or in for checks. I do remember when I was first dx'd, the doc told me "high grade" because mine is intermittent, meaning they cannot tell when the signal will be lost therefore making it more dangerous than usual. Although, reading your explanation, I would now disagree with the doc. A lost signal is a lost signal - doesn't matter when or how often! Again, thanks. If you think of anything else to add, please let me know.

High grade blocks

by lenora - 2009-12-30 08:12:41

Mobitz type 2 second degree can progress to high grade complete or 3rd degree AV block. There's a very slow ventricular escape rhythm and the patient can't maintain systemic blood perfusion with such a low heart rate. Blood pressure is low. Requires immediate pacemaker implantation.

High grade block

by ElectricFrank - 2009-12-31 12:12:01

This is the kind of block us upper class folks get!! LOL

Might be a good one to put on my grave stone. "He had an upper class heart"

Seriously, it seems to be just another term for complete AV Block. There are all sorts of terms floating around out there. My guess is that many are attempts on a doctors part to explain the situation in a way a patient can understand it.

High-Degree Definition

by pacemaker writer - 2010-01-01 07:01:40

High-grade heart block is a term pacemaker writers use to describe 2nd or 3rd degree heart block. TraceyE had a great definition.

The issue is what happens at the AV node. In a healthy heart, the electrical signal is slowed slightly as it goes through the AV node. This makes sure the atria contract first and can relax before the ventricles contract.

In first-degree heart block, the electrical signal slows down way too much in the AV block but still gets through. Think: delay.

In second- and third-degree heart block, some to all of the signals get blocked. There are lots of variations (there are 2 specific types of second-degree AV block) but "high-degree AV block" means that the atria and ventricle are mostly not talking to each other or totally not talking to each other.

Don't be embarrassed that you're confused. Heart block is a very complicated condition with lots of variations!

By the way, Happy New Year!

You know you're wired when...

You have rhythm.

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