Nitro resolving ST elevation; evidence ?

[zzyzx]

Anecdotaly I have heard of nitro resolving ST elevation. Is there anyone aware of a study that actually confirms this?

 

[VFlutter]

I do not know of any studies but I have personally seen it happen a few times. Especially with intracoronary nitro in the cath lab. But all anecdotal.

 

[NPO]

Out of curiosity... Is the idea here vasodialation of the coronary vessels to clear a thrombus?

 

[Carlos Danger]

Not to clear a thrombus but to increase flow to the myocardium through vasodilation.

I have seen ST resolution with nitro. EKG changes with IV nitro and beta blockers aren't uncommon.

 

[KellyBracket]

Anecdotaly I have heard of nitro resolving ST elevation. Is there anyone aware of a study that actually confirms this?

Yes & no. The phenomenon of spontaneous reperfusion (SR) of a STEMI is well-described, with research studying predictors of SR, prognosis after SR, etc. However, there isn't much out there suggesting that the relationship between SR and ASA, NTG, or other acute therapy, is anything other than coincidence.

I wrote a short review of the topic When the STEMI disappears before you get to the ED! I point out that some people (e.g. Dr Stephen SMith) are pretty convinced that NTG does cause SR, and give a link so you can check out their perspective as well.

The common theme, however, is grab ECGs early, and often! EMS is in a unique position to document the early phases of ACS, and the data you acquire may significantly decide in-hospital course.

 

[TomB]

Back in 2008 David Hildebrandt (Hennepin at the time) presented a poster presentation and abstract to NAEMSP showing 7% of STEMIs normalized by arrival in the ED. All patients who normalized had positive troponins and PCI was not delayed because the ST-elevation had normalized. They speculated it could have been due to the NTG, O2, or spontaneous reperfusion but they did not study which it was. There was no control group, no set of patients that did not receive NTG.

 

[TheLocalMedic]

Back in 2008 David Hildebrandt (Hennepin at the time) presented a poster presentation and abstract to NAEMSP showing 7% of STEMIs normalized by arrival in the ED. All patients who normalized had positive troponins and PCI was not delayed because the ST-elevation had normalized. They speculated it could have been due to the NTG, O2, or spontaneous reperfusion but they did not study which it was. There was no control group, no set of patients that did not receive NTG.

I've had it happen to me once. Initial 12 lead showed significant ST elevation and so did a few subsequent others (I'm one of those guys who snap off several for every STEMI. En route (after ASA, NTG and O2 were all given) the monitor printed its own strip (for those unfamiliar the LP 15 will shoot out another 12 lead if there are changes) that showed normal ST segments in all leads. Surprised the heck out of me and I snapped off a few more that all showed the same thing. The patient even reported significant decrease in chest discomfort to boot. Not sure what caused it, but I know that he was still sent to the cath lab pretty quick.

 

[zzyzx]

Thanks for the link to your excellent blog. I've read most if your entries in the past, but haven't kept up with it like I should. You may want to consider also doing a podcast. Podcasts are so convenient to listen to for people who live super busy lives (ie most if us ). Your blog really is very good and it deserves a wider audience.

It is interesting that there are so many physicians and paramedics who insist that you must do a 12 lead before giving nitro, and yet there apparently is no real evidence that it will "erase" ST elevation. H

 

[Rialaigh]

Thanks for the link to your excellent blog. I've read most if your entries in the past, but haven't kept up with it like I should. You may want to consider also doing a podcast. Podcasts are so convenient to listen to for people who live super busy lives (ie most if us ). Your blog really is very good and it deserves a wider audience.

It is interesting that there are so many physicians and paramedics who insist that you must do a 12 lead before giving nitro, and yet there apparently is no real evidence that it will "erase" ST elevation. H

I believe this has more to do with not giving nitro, or very carefully titrating with nitro paste, on posterior MI's. I'm not giving nitro without a 12 lead, I will apply paste without a line depending on their pressure and symptoms, but not going blindly giving it.

 

[TomB]

Thanks for the link to your excellent blog. I've read most if your entries in the past, but haven't kept up with it like I should. You may want to consider also doing a podcast. Podcasts are so convenient to listen to for people who live super busy lives (ie most if us ). Your blog really is very good and it deserves a wider audience.

It is interesting that there are so many physicians and paramedics who insist that you must do a 12 lead before giving nitro, and yet there apparently is no real evidence that it will "erase" ST elevation. H

There is enough reason to believe that it will erase ischemia in general. Don't forget about ST-depression. NTG is a potent coronary vasodilator. It can absolutely reverse ST-elevation when coronary vasospasm is involved (happens in the cath lab all the time when given intracoronary). "Hasn't been studied enough" isn't the same as "no evidence."

 

[zzyzx]

There is enough reason to believe that it will erase ischemia in general. Don't forget about ST-depression. NTG is a potent coronary vasodilator. It can absolutely reverse ST-elevation when coronary vasospasm is involved (happens in the cath lab all the time when given intracoronary). "Hasn't been studied enough" isn't the same as "no evidence."

Do you have links to studies showing that IV nitro reverses ST elevation?

 

[TomB]

Do you have links to studies showing that IV nitro reverses ST elevation?

Re-read what I wrote. Resolving ST-depression, all by itself, is sufficient reason to perform a 12-lead ECG with the first set of vital signs, and before MONA. When the blood work comes back negative, the prehospital 12-lead ECG may be the only solid evidence that the patient's chest pain was cardiac in origin.

 

[zzyzx]

Got it , thanks.