NTG and bradycardia

[tech1000]

I have given SL nitro a ton of times in my time being a nurse. Yesterday I gave a woman one dose of SL ntg. About a minute after giving it, she said she didn't fell well at all and felt like passing out. I tried to lay her back thinking it was just from an initial drop in BP because of the vasodilation, but she said she felt worse laying and sat right back up. Her HR was about 100 when I first gave it and then I noticed her HR trending down. It was in the 80s and I went to ask the MD to come in the room (she was just down the hall). In the 5 seconds I was gone, the husband asked another nurse to come in cause she had convulsions. Her HR when I got back to the room right after was 57, she was diaphoretic and pale, but she said she felt better already. Her HR went right back to 100 and she was totally fine. The only thing I could find about this was somebody saying it could be Bezold-Jarisch reflex. I had a BRAND NEW doc with me and all she said was "oh, it's cause she has the flu. Give her some fluids." I know that wasn't it though.

Aside from having the flu (and she had been sitting up the whole time if it could be the Bezold-Jarisch reflex, but I can't find a ton of info on that other than articles that I have to pay to read), she had T wave inversion, which she said was not new, and upper back pain. She was admitted before ever having a stress test, so no idea what came back, but her cardiac enzymes were normal. Also, her back pain totally resolved after this incident. And she had no other history that I can recall.

Has anybody ever had this happen or have input on it? I may check with one of our more seasoned docs tomorrow when I go back, but it was just really strange. (And I added NTG to her allergy list under adverse reaction- not doing that again!)

[CraigB-RN, MSN, RN]

Usually that's a reperfusion event. But it is usually transient. Scarry but like a vagal response self correcting.

[SpEdtacular, MSN, RN, EMT-P]

I have had a patient's heart rate drop from the 80s to the 40s because her chest pain turned into an inferior wall MI, but in that instance it stayed dropped. Although it doesn't sound like it was the case with your patient, a patient having a right-sided and/or inferior wall MI can become bradycardic and nitro can cause the patient to decompensate because the patient is preload dependent. The patient might have vagal-ed too, I have had that happen especially after starting IVs, or it could have just been a coincidence. There's always that.

[Loo17]

I have had two different patients in the past month become bradycardic after nitro, never before that. One patients rate dropped from 90's to 40's then after 500 ml NS and 5 minutes, returned to baseline. Aside from the low rate there were no notable ECG changes. The other went as low as 38 and returned to baseline in the same manner. Neither patient became hypotensive.

The docs were not able to tell me why this happened other than it was transient.