Dual Lead Medtronics

dual chambered PM

by 0o0 DC 0o0 - 2017-10-27 08:27:29

My situation is kind of the other way round, my SA node wasn’t functioning correctly but my AV node is currently fine. Despite this I had a dual chambered PM placed with both leads activated. Even though I only really needed atrial pacing there is an understanding that in this scenario AV node conduction abnormalities often develop as you age. Having a ventricular lead in place means that should this arise then they don’t need to operate any further to place another lead.

Single lead ventricular PM are primarily used to generate an effective heartbeat in patients with chronic Afib alongside a slow ventricular response, as the AFib would still produce effective atrial stimulation (despite being erratic) all that is needed is the appropriate ventricular response, which a PM with a ventricular lead will produce.

In your Mum’s situation, I imagine that the atrial lead has been put in as a fail safe should her natural atrial stimulation stop being effective for some reason, that way they can just activate without any further surgery should it be needed. There may be other reasons too though (or that could be incorrect) so I would wait for others to pitch in with their answers too :)!

Atrial fibrillation pacing and atrial flutter.

by Selwyn - 2017-10-27 09:44:27

Good question!  As I see it, if she has atrial flutter, she cannot have atrial fibrillation at the same time.  Her AV node is obliterated. The norm, is dual  chamber sensing and dual chamber pacing. Single ventricular pacing is associated with a poorer outcome ( heart failure) due to the incoordination of the atria pushing against the closed interchamber flap valves ( mitral and tricuspid). 

A DDDR device is commonly prescribed after AV nodal ablation, together with automatic mode switching to avoid rapid ventricular tracking of AF. Arguably, because of poor long term sinus maintenance in this resistant group, and in those with persistent AF before ablation, a VVIR device may be an alternative, as you suggest.( (see http://anesthesia.slu.edu/pdf/pacemaker.pdf if you are not familiar with pacing mode classification)  

It would seem that your Mum does  have an active   SA (sinoatrial)  node. The generated pulse is going in a circular motion around the tricuspid valve of the right ventricle, causing flutter. 

The AMS mode of the pacemaker ( automatic mode switiching), will be active so that the ventricles are not paced at the rate of the circular circuit of flutter. A DDD device is indicated as she has some SA node activity still.  The ablation for atrial fibrillation is around the pulmonary veins and leaves the SA node functioning.

I hope this sheds some light on the question 

Selwyn