low heart rate

hypocaffeinemia, BSN, RN · Oct 25, 2008

About eleventy billion things.

The most likely suspects are medication or sick sinus syndrome, but without knowing more it's just speculation.

SuesquatchRN, BSN, RN · Oct 25, 2008

Generally, the SA node fires at 60 - 100 BPM. If that fails the AV takes over, at I think 40 - 60. If THAT fails the Purkinje fibers kick in, at 20 - 40. I think those are the usual rates.

So the electric company, the SA, has a blackout and the back-up generator, the AV, ran out of fuel. So you have someone on a bicycle, the Purkinje fibers, pedaling furiously to keep a charge in that battery.

A number of things can cause this.

leslie :-D · Oct 25, 2008

dang, it could be a millions things.

cad, valve problems, pump malfunction, sclerotic vessels, electrical, meds (digoxin, beta, calcium ch blockers), hypothyroid, lung disease...and often, idiopathic.

but i agree that you likely r/o sss and meds.

leslie

Jarnaes · Oct 26, 2008

Resting HR in the 30's... could also be Lance Armstrong or Michael Phelps, but I guess those guys don't c/o dizziness... :yeah:

loricatus · Oct 26, 2008

If this wasn't a chronic condition & was an isolated incident, I would suspect a vasovagal episode.

If this was her baseline, ditto on what others have said.

Virgo_RN, BSN, RN · Oct 26, 2008

Was the pt. on tele, or did you get an EKG? Was it a sinus rhythm?

Virgo_RN, BSN, RN · Oct 26, 2008

Generally, the SA node fires at 60 - 100 BPM. If that fails the AV takes over, at I think 40 - 60. If THAT fails the Purkinje fibers kick in, at 20 - 40. I think those are the usual rates.
So the electric company, the SA, has a blackout and the back-up generator, the AV, ran out of fuel. So you have someone on a bicycle, the Purkinje fibers, pedaling furiously to keep a charge in that battery.
A number of things can cause this.

In theory, yes, this is true. But, just because the rate is low, does not mean it is originating in the AV node or the ventricles. Sinus bradycardia originates in the SA node, and can go as low as the 20s-30s. The AV node and purkinje fibers don't necessarily kick in and take over the pacemaker function when the SA node is firing at a low rate. People can have sinus pauses that last for several seconds with no junctional or idioventricular beats. Real hearts don't always fall neatly into the categories we learn in EKG class. Without an EKG, it's not really possible to say what was happening in this case.

Flightline, BSN, RN · Oct 26, 2008

Was the pt. on tele, or did you get an EKG? Was it a sinus rhythm?

Hey Virgo (me too, by the way--actually on the cusp, Sep 22), assuming everything reported is accurate, could a pt have a sinus rhythm that low? I suppose they could if they had too much dig, or beta blockers or something, but you'd think there would be an escape rhythm--a junctional rhythm of some sort or ventricular escape beats.

The OP must give us more info.

Ah, I see you posted the answer to my question. Beat me to the punch as it were.:typing

Virgo_RN, BSN, RN · Oct 26, 2008

I've seen sinus brady that low, and no, you won't always see escape beats.

hypocaffeinemia, BSN, RN · Oct 26, 2008

I've seen sinus brady that low, and no, you won't always see escape beats.

I see sinus rates that low almost daily (monitor tech), and almost never do any of the downward pacers kick in.

Virgo_RN, BSN, RN · Oct 26, 2008

In a little over a year, I've seen a junctional rhythm once. I've never seen an idioventricular rhythm.