Lidocaine Toxicity CAUSING v-tach?

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Specializes in Neurology.

Hi everybody,

I'm trying to understand how lidocaine toxicity can CAUSE ventricular tachycardia?

I work on a Neurology unit as an RN and we have this one doctor who only treats migraine patients from his own practice. When they get out of control migraines that they aren't able to manage at home, he admits them and uses some rather unusual outsidse-the-box treatments, one of which is a continuous lidocaine drip.

Now I've only been there for about 6 months so I've only personally worked with two or three of his patients, but today I had one of his patients on a lidocaine drip start having runs of v-tach. An hour or so later her tele strips looked like she was in primarily v-tach with random runs of sinus rhythm. We ended up shipping her off to the cardiac unit and d/c'ing the lidocaine, but for the life of me I cannot figure out how a lidocaine drip can cause vtach??

The doc was stumped as well, and I called the pharmacist and asked but he was swamped so he couldn't look into it (and she was off our unit anyways.) When I told my coworkers, none of them were really surprised though and they said that's what happens with lido toxicity and that this doctor's patients always end up super tachy.

Now, I thought that lidocaine blocks sodium channels and causes BRADYCARDIA and heart block. I saw it can also cause seizures and malignant hyperthermia, but the pt had no s/s of either. Any thoughts? The pharmacists best guess was that the lido interacted with another one of her meds and caused the vtach. That wouldn't explain why all my coworkers say their lidocaine patients are always tachy!

Any thoughts??

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Specializes in Anesthesia.

Bupivacaine-induced cardiac arrhythmias in sheep. - PubMed - NCBI In this study 100% of the animals had sinus tachycardia when exposed to high doses of lidocaine.

Certain medicines can increase the rate of cardiac dysrhythmias with local anesthetics (beta antagonists, calcium channel blockers, digatoxin). Already increased HR can also lead to a greater degree of sodium channel blockade in the heart, and high doses of local anesthetics will increase the PR interval and widen the QRS complex.

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Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.

It can change the conduction through the ventricles widening the QRS and developing a long QT syndrome which can precipitate V Tach

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Specializes in Critical Care, ED, Cath lab, CTPAC,Trauma.
Arrhythmia: Long Q-T Syndrome | Cleveland Clinic
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