ECG - 3rd degree AV block?

Re: ECG - 3rd degree AV block?

Martin Atkinson — Wed, 07 Sep 2011 10:53:30 GMT

Looks like a 3rd degree heart block to me, the QRS complexes are bizarre and wide so look like VPCs rather than triggered by the P wave but they are mono-focal which improves the prognosis, they are fast for an esacape rythmn it doesn't excude this. You say there is a pulse deficit but don't say what the pulse rate is - if it is a lot slower than the heart rate. Given the breed this is most likley to be secondary to cardiomyopathy, X-ray and echo would be useful and try a Cardiopet proBNP. If the owner won't go for a pacemaker I would try pimobendan, which may improve cardiac function all round and reverse some the changes which have led to the heart block

Re: ECG - 3rd degree AV block?

Anonymous — Tue, 06 Sep 2011 21:02:00 GMT

Thanks for replies.

For anyone interested in follow-up:

Spoke briefly to cardiologist I'd sent the ECG to today. Didn't have much time to chat as in meeting, but from what he said, I think it is a 3rd degree AV node block. He said the only treatment was a pacemaker, but at £2500-£3500 I doubt the client will go for it. He suggested that just because the ventricular rate was 70bpm at time of ECG doesn't mean that isn't significant bradycardia or even asystole at time of collapsing episodes (he thought this was much more likely than a ventricular tachycardia happening); he also said that the level of output from the systoles was unknown and may be poor. Unfortunately, didn't have time to explain the ECG in more detail, but I think the last comment must refer to the compexes being ventricular rather than supraventricular - would be interested to know what his thoughts on the rate of these (I still presume escape beats?) was at least twice what normally expect with 3rd degree AV node block?

Dog collapsed just once in last 24hrs and only went down on hindlegs, not forelegs.

Re: ECG - 3rd degree AV block?

Kirsten Simpson — Tue, 06 Sep 2011 17:01:42 GMT

I've only seen one 3rd Degree AV block and the dog presented collapsed and couldn't stand, HR was between 15-30bpm. This one looks/sounds more like 2nd Degree AV block Mobitz type 2 variation? Have you tested it with Atropine? (I like cardiology but don't see enough, so this is just my own postulating, not an expert at all!)

Re: ECG - 3rd degree AV block?

Stephen Courtney — Mon, 05 Sep 2011 21:37:44 GMT

I think you'll have to wait for a definitive word from your cardio guy, but I would expect a 3rd degree block to show an escape rythm - ie a much slower heart rate than you appear to have there, in addition the ventricular complexes should be identical. the two cases I've ever seen were fairly lethargic due to bradycardia, so they were the easiest ECGs I've ever done. Your traces look good and i think you'll get some useful info.

If you think the collapses are cardiogenic the next step is a holter monitor but based on the number of odd beats you picked up, I doubt it would show much. but you never know unless you try, this dog may shower out bizarre complexes at erratic intervals - hence the value of a holter.