What is vagal tone?

I have a cardiac arrythmia (multifocal atrial tachycardiac) caused by a wandering atrial pacemaker. Google tells me this is generally caused by COPD or other serious conditions, and if not these then by “variations in vagal tone.” I don’t have COPD or heart failure or some other serious condition they could find, so they just put me on a beta blocker shrugged and sent me on my way.

I looked up vagal tone and don’t understand what it is at all. Can someone explain it to me in simple terms that I can understand?

I didn’t put this in IMHO even though it is medical because I am not seeking advice, merely explanation. Can anyone dumb down the explanation for me?

What’s being referred to is autonomic tone.

More info here

sorry, can’t stay to elaborate.

I’m not a doctor at all but I can try since nobody has responded… The vagal nerve is like a data cable connecting between your brain (specifically the medulla oblongata) and multiple organs including your heart, eyes, lungs, digestive tract, etc. It is responsible for sending signals from your nervous system to those organs when they are at rest, kind of like your car engine when it’s idling as opposed to when the car is moving. The vagal nerve’s actions are automatic (you don’t consciously control it) and constant, running passively. The “vagal tone” is just a term for what the vagal nerve is doing. If the vagal nerve was the cable that connects your TV to the cable company, the vagal tone would be cable service providing you the shows you watch.

Vagal tone, in regards to your heart rate, is what slows down your heart when you’re resting.

Isn’t there something about treatment of clinical depression associated with the vagus?

  • off to Google *

ETA: First grab

Vagal tone as an indicator of treatment response in major depression
a1 Department of Psychology, University of Arizona, Tucson, Arizona, USA

Increased vagal tone has been associated with treatment success using pharmacological agents and cognitive-behavioral treatment in major depression, but not using electroconvulsive therapy. The present study investigated whether increases in vagal tone would be associated with favorable treatment response with nonpharmacological treatment. At baseline and following treatment, 16 subjects were administered the Hamilton Rating Scale for Depression (HRSD) followed by electrocardiographic recording. Those with little change in vagal tone from before to after treatment showed minimal reduction in HRSD score (−4.8); those with larger vagal tone change showed a large decrease in HRSD score (−14.8). Changes in vagal tone are thus related to favorable treatment response in depression, and do not represent anticholinergic pharmacological effects. Future work manipulating vagal tone might prove informative in teasing apart the causal role of vagal tone and depression.

These are good responses. In case the term that is confusing to you is the term “tone”, it may be helpful to thing of it in terms of “muscle tone”.

If you gently squeeze your bicep muscle, you will feel some firmness, even at rest (that is awake, but no activity). If you actually flex your arm, you will feel more firmness. If you flex against resistance, you will feel even more firmness. These all represent different degrees of muscle tone, appropriate for different situations. Even at rest there is still some activity. When you are unconscious, the tone is even less than at rest. (If the nerve to the muscle is cut, the muscle becomes entirely flaccid.)

The Vagus nerve (and many other nerves) are similar. They are constantly active to some degree, even when they are not ‘actively working’. The Vagus nerve supplies parasympathetic stimulation and works in opposition to the sympathetic system. The body likes to have both sytems running, even if one is just “idling” (as Atamasama said). One analogy is that it idles for the same reason a bank heist getaway car driver idles- to be ready to jump in at a moment’s notice. I personally envision these opposing systems (very common in biologic situations) as opposing ‘pincers’, better able to hold physiology at precise points.

Too much or too little vagal tone for a given situation begets a slower or faster heart rate than normal (among other things).

Thanks guys for responding. I understand a little better. but I think this will remain beyond my understanding. I just was trying to understand how this relates to my heart’s pacemaker wandering around. The irregular heart beat is very disconcerting. Doc said today they will put me on a monitor for a few days. Thanks again for trying to help me with this.

Let me see if this helps.
You have a normal pacemaker that gives off an electrical signal that tells your heart to beat.
When you have a wandering pacemaker it means that different parts of your heart also give off electrical signals that can stimulate a heartbeat.
Normally, the main pacemaker is the strongest and by the time the heart has relaxed enough to beat again, the signal from the main pacemaker comes through to create another beat. However, if the main pacemaker is too slow, one of the other signals can come in and make the heart beat out of rhythm (like a syncopated beat).
The vagus nerve control the main pacemaker. Vagal tone refers to how strong the vagus signal is. When the vagus nerve tells the main pacemaker to slow down then these other beats can come in and your heart rhythm is irregular.

If you label the main pacemaker A, other areas of electrical activity b,c,d etc and a heartbeat HB, it can look like this:

normal: A…HB…A…HB…A…HB…A…HB…A…HB…A…HB…A…HB
increased vagal tone: A…HB…b…HB…A…c…HB…d…HB…A…b…HB…A…HB

Thank you psychobunny. I get it now. It doesn’t explain why this is happening, but at least now I understand how it works.