EKG changes in different leads

[Dustdevil]

Because AHA is always right!

Bretylium, anyone?

[UMSTUDENT]

Because AHA is always right!

Bretylium, anyone?

Beat me to it. If AHA was the definitive source of knowledge on all things cardiac people wouldn't spend years in fellowship to become board certified cardiologist. There are at least a few studies that will detail how much of an interpretive science ECG "reading" really is. I believe one study* showed that a computer beat out a world famous cardiologist by almost 20% in diagnosing confirmed MIs.

*Heden, B., Ohlin, H., Rittner, R., and Edenbrandt, L., "Acute myocardial infarction detected in the 12-lead ECG by artificial neural networks," Circulation 96 (1997) pp.1798-1802

As found from the book Complications: A Surgeon's Notes on an Imperfect Science by Atul Gawande.

[flight-lp]

Whats wrong with Bretylium Dust? Isn't it still first line along with Procainamide, Isuprel, and Propanolol?

o.k. maybe the AHA refrerence wasn't the best reference example, but it is still correct..............................

[Dustdevil]

If I remember correctly from the last time I studied 12 leads about 20 years ago, Dubin say's you're both right.

V1 and V2 are septal.

V1 through V4 are anteriour.

The difference is that in a septal, you'll get ST depression. In an anteriour, you will get ST elevation.

But then again, it's been awhile. Anybody have a Dubin book to check? I trust him more than any other source.

[zumjus]

If you get depression in the Septal leads (v1, v2), especially with a tall R waves, then that would be a reciprocal of a posterior MI. Elevation in Septal lead would indicate septal MI.

My two cents: I agree that lead 2 is pretty much worthless in 3 lead unless you need to tell speed (or major obvious cardiac arrythmias, i.e. V-Fib/V-Tach/Asystole/etc. etc. etc.). We use 4 leads and 12 leads in my system and I prefer looking at leads 1 and AVF instead of lead 2 when using a 4 lead (it tells me more about their cardiac status then lead 2 does). Doing the "modified 12 lead" with a 3 lead, by moving the leads around, is still not very helpful. I know they used to do it, but luckily testing and research has revealed that it is not a very good indicator of MI. Hell we used to shock Asystole too, but we now know that isn't a very good idea anymore, or helpful either. The monitor needs to be in diagnostic mode (like a 12 lead does, not 3 lead). Just because you are moving around the leads, doesn't make it any more diagnostic if the monitor is in monitoring mode. I don't know how many times I have taken a person into the ER with elevation showing in leads 2/3, but the 12 lead showed nothing going on in the inferior leads. The nurses are quick to freak out, until I show them the 12 lead. Here is an idea, if the patient is having CP or a CP equivalent then treat them like they are having an MI regardless of whether or not the monitor shows elevation or not. If your service doesn't have a 12 lead monitor, then raise the money to get one. The are essential now and standard of care. Of course if I had to choose between a 12 lead and CPAP, I'd go with CPAP everyday of the week, and twice on Sundays.

[jmac]

my two cents worth,

i am enjoying this and its very good reading, just want to say that regardless of the monitor, 3 lead or 12, they can both misinform you at times, i had a case of psuedonormalisation a couple of weeks ago, this is where the t-wave after an old incident is inverted and with a new episode of chest-pain or possible MI the t-wave reverts to normal, i am told this is rare, this was my first case, so i treated the PT and not the monitor.

Its little things like this that keep you on your toes, the EKG appeared normal in all leads and the PT had to be monitored for a period of hours before signs of damage showed, so it just goes to show sometimes we can become attached to our mechanical friends, but its better to take a look at the history and the PT,

keep safe.

[zumjus]

That's interesting. I will have to ask around about that.

[Dustdevil]

Its little things like this that keep you on your toes, the EKG appeared normal in all leads and the PT had to be monitored for a period of hours before signs of damage showed, so it just goes to show sometimes we can become attached to our mechanical friends, but its better to take a look at the history and the PT,

Absolutely! Good job! There is a mistaken belief by many that "treat the patient, not the monitor" somehow doesn't apply to 12 leads. Dead wrong. That's why the ER doc runs cardiac enzymes AND an EKG instead of just one or the other.

[Ridryder 911]

You should be treating several factors as Dust describes.. the old silent AMI, we have seen so many times in patients that so happened to be examined because of another c/c such as a fall or non related trauma. I look at treating AMI like a jig saw puzzle.. sometimes there are many pieces .. sometimes, you get luck and the puzzle is easy to figure out..

R/r 911