Mobitz I and Mobitz II

I understand the descriptions for Mobitz I and Mobitz II grade 2 type heart blocks.

What I am struggling with is what would the explanation be for having both in the same person.

I know I have a long PR interval and I know the EP said that sometimes my heart would drop a beat after increasingly lengthening PR intervals. That makes sense and would come under  Mobitz I and suggest I have a problem with the AV node.

However I also at one point was in a 2:1 block. So this suggests a Mobitz II. 

The literature suggests Mobitz I very rarely progresses to full heart block.  

Mobitz II can progress to full heart block as they have problems with the bundle of His.

My question is, what is the explanation for me having both Mobitz I and II during those few days I was on ECG? 

Does it suggest I have problems in both by AV node and bundle of His?

Thanks John


an assortment of diagnoses

by Tracey_E - 2021-01-11 11:05:30

It's common to have a bit of a mixed bag with electrical problems- sometimes a little of this, other times a little of that. The electrical system is faulty. You can drive yourself crazy overthinking it. If it progresses, you've already got the fix in place. 

I see so not black and white but a bit of grey

by quikjraw - 2021-01-11 11:11:49

I understand Tracey_E, the literature sort of suggests at any one time you are one grade or another but it can be literally all of them then.



by Tracey_E - 2021-01-11 11:15:16

If I went through every cardiologist I've had over the years and read the files, each of them would have something different in their charts. None are right or wrong, I think of it as fluid. Botton line is faulty wiring. 

I know, faulty electrics are frustrating, uncertain and trigger lots of questions

by Gemita - 2021-01-11 12:19:25

John, to put it into perspective, why can my crazy heart one minute be in Atrial Fibrillation, the next switch to Atrial Flutter, the next to Non Sustained Ventricular tachycardia, the next minute be back in normal sinus rhythm, the next minute be tachycardic/bradycardic, the next switch to bundle branch blocks, first right then left, then go on to Multi Focal Atrial Tachycardia, then to Supraventricular Tachycardia??  I have electrical disturbances that are wild, unpredictable, fluctuating, intermittent, fast, slow, regular, irregular, persistent/non persistent.  This is the nature of electrical disturbances.

Your Mobitz blocks can change from one moment to another, it may stay the same for lengthy periods, then suddenly change when you least expect it.  Mobitz like all electrical disturbances may change according to stress, infection, trauma (like surgery), medication changes, heart disease, fibrosis/sclerosis of the conduction system, inflammatory conditions, vagal tone, anaemia, Lyme disease and so on.  I expect you had a full work up John of potential causes prior to pacemaker implant but if not you could always ask specifically about further testing to give peace of mind.

John now that you have a pacemaker, all your questions can be safely answered over a long period because you are safe from any sudden deterioration in your symptoms.  Over time, as your electrical problems settle, get better or worse, all your questions will be answered.  I was like you (and still am) but I realise that this will be a process that I and my doctors will have to go through, an ever changing process, that is the nature of electrical disturbances.  But I am no longer afraid of the turmoil that is occurring sometimes in my heart because I am slowly putting a name to all the different rhythms that are dancing around.  I am able to ignore them most of the time because my pacemaker and beta blocker are taming them into submission (!). And do you know, with quiet acceptance, knowledge of the nature and type of arrhythmia I have present, they are not making the impact they once did.  I am sure it will be the same for you too very soon as you begin to rely on your pacemaker, accept that it is a part of you and is there to support you, does that make any sense?  

Mobitz-1 vs. Mobitz-2

by AgentX86 - 2021-01-11 15:21:52

IIRC, Mobitz-1 is caused my the A/V  node itself and is usually caused my external factors (drugs, illness, etc.). When the external factor clears up so does the arrhythmia. A pacemaker is not necessary.

Mobitz-2 is caused further down the chain. As you note, perhaps the bundle of His. This isn't reversible and will usually degenerate into 3rd degree heart block. A pacemaker is needed.

Mobitz 1 and 2 and other electrical problems

by Sisterwash65 - 2021-01-11 19:22:20

I agree with those previous comments and would like to add that I was diagnosed with 1st degree, Mobitz 1 and 2 and complete Heart Block - All in the same day. It is documented in my records. We have all had the experience with any electrical appliance that isn’t working right, so you jiggle the cord and it comes on... Then it’s working again. That’s what happens in our heart when you have conduction problems. The pacemaker is our backup. Thank God for pacemakers !

You know you're wired when...

You can finally prove that you have a heart.

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