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Right Sided MI - How Do I Tell The Difference

38 posts in this topic

Posted · Report post

OK help a student learn the differences. Start at the basics and go deep for me. What physical differences, what EKG differences (maybe post a strip showing), what is going to differ in treatment?

No this is not homework as I have completed my Paramedic course except clinicals. I actually did a paper on this but now want more, don't want no mistakes when I'm the Paragod in charge ;) .

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Posted · Report post

I think the old worn saying says it best. Treat the patient, not the monitor. Common sense is also key.

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Posted (edited) · Report post

As far as EKGs go - I read somewhere that if the ST elevation in lead III is "taller" than in lead II, you will probably have a right-sided MI. Dunno how accurate this is, but any googling of "right-sided MI" would seem to show this...

right.gif

Edited by scott33
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Posted (edited) · Report post

If 12 lead shows ST elevation in the inferior leads conduct a modified twelve lead looking for ST elevation in V4R with any two of II, III and avF. Also consider this rule of thumb, if the ST elevation is higher in lead III over lead II it is more likely that the RCA is involved over the circumflex branch (which only suuplies the inferior wall in ~20% of people).This may indicate a potential RVI or in may indicate and inferior wall MI.

In terms of clinical presentation look for JVD, or more specifically Kussmaul's sign where JVD becomes evident on inhalation. Expect hypotension due to reduced cardiac output. Expect lung sounds to be clear (pertinent negative to rule out cardiogenic shock)

Since RV AMI's occur most often due to occlusion of the right coronary artery expect that the RVI may occur in conjuction with an inferior wall MI. As such expect clinical signs of inferior MI such as nausea and vomitting due to vagal stimulation. Vagal stimulation may lead to an underlying sinus bradycardia or AV block.

Had to hit the books briefly to make sure I had the details right, but I surprised myself and remembered almost all of that. *Pat on back to self*

I think the old worn saying says it best. Treat the patient, not the monitor. Common sense is also key.

I don't follow on this at all. Common sense doesn't tell me dick about left vs right side MI. Common sense might tell me big fat guy, chain smoking with a huge cardiac history is more likely to have an AMI and keep my index of suspicion high, but this saying is for once incorrect. I cannot be sure (from my understanding) that a patient is not having a RVI without a 12 or 15 lead to rule out RV involvement. If I don't treat the monitor and jump to MONA than I'll drop their preload and potentially place the patient up a creek.

Don't confuse common sense with good, well-honed clinical judgement tempered by experience. Common sense lets us say "yep, you need a dressing for that bleedin." Clinical judgement let's us say, "these signs and symptoms suggest an MI, and the Kussmaul's sign, BP and N/V are making me think inferior or RVI. Let's take a closer look."

Cheers.

Edited by DocHarris
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Posted · Report post

spenac, get yourself the Garcia EKG book and make it your best friend (eat with it, pee with it, sleep with it just don't get the pages stuck together).

wrmedic, I have to disagree. I hate that saying because it is completely untrue. Your pt will not tell you, "I am having a right sided MI, you should be cautious with the nitroglycerin," but your EKG will. The pt can only describe the symptoms. It is the monitor/EKG that will give the diagnosis and guide your treatment.

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Posted · Report post

Right Sided Inferior Myocardial Infarction = Leads II, III, and aVF.

right.gif

It definitely helps to look at the monitor....watch your nitros with right sided heart failure.

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Posted (edited) · Report post

Common sense doesn't tell me dick about left vs right side MI.

haha, made me lol.

I agree though. For the most part the difference between a right and left sided failure will not be obvious at the outset. There are a few physical symptoms you can look for though, even though they are neither specific nor sensitive indicators of right heart failure.

Distal edema/JVD in the absence of pulmonary edema points to right heart failure. If you think about where blood goes as it passes through the heart, a failure of the right side should result in venous fluid backup. This results in distal edema and JVD.

Pulmonary edema in the absence of distal edema, by the same rationale, should raise suspicion for left heart failure.

There is a caveat, though. Right and left heart failure are rarely independent of eachother. In fact, the most common cause of right heart failure is left heart failure. So, often we will see mixed symptoms and these indicators above will be worth squat. They are an interesting thing to keep in mind, though.

As far as treatment of the patient with right sided failure, you need to remember the Frank Starling law. The law states that stroke volume (and therefore cardiac output) is directly related to cardiac input ("preload"). It has to do with the stretching of the muscle fibers of the heart. Like an elastic band, the farther they are stretched, the more forcefully they contract. Patients with right heart failure have muscle dysfunction such that they become increasingly dependent on preload to mediate cardiac output. This is why we need to be careful with nitrates, as their primary function is to increase peripheral vascular pooling and reduce preload. Decreasing preload in a preload-dependent patient will rapidly reduce stroke volume, cardiac output, and blood pressure.

Edited by fiznat
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Posted · Report post

sorry...I just saw that I had posted the same pic as scott33. No intentions of being a jerk here.

~Ec

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Posted · Report post

It's all good. First picture google images will come up with

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Posted · Report post

Sounds like a good future strip tease.

Move V3 or V4 to opposite side of chest. (or both, or entire 12-lead). Don't expect to see tombstones, RVMI usually displays with 1-2mm of elevation. Avoid nitrates or other preload reducers, and administer fluids as needed.

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Posted · Report post

So I move v1-6 over to right side how will that change the things seen on my 12 lead? Will it change my QRS, etc? What does it actually tell me?

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Posted · Report post

So I move v1-6 over to right side how will that change the things seen on my 12 lead? Will it change my QRS, etc? What does it actually tell me?

Actually you leave V1 and v2 in place, moving just V3-V6 (although I recently saw a text that just moved V4-V6...not sure if there is any real difference there).

This gives you views of the right side of the heart through the right side of the chest. Similar to moving your leads around for V7 through V15 will give you your posterior view instead of hoping for riciprocal changes in V1-V2.

Remember your precordial (V) leads are UNIPOLAR, looking only from their specific locaion, where your "limb Leads" (I, II, III, AVL, AVR, AVF) are BiPolar, meaning they need two leads to assess their "view". This is why moving your V leads can be useful.

Any-who....Moving your V3-V6 over to look at V3r thu V6r will enable you to assess for ST elevation or other signs of Ishemia/infarction specific in location to the right side of the heart.

Just a thought, but with out going back to the OP, you do understand your lead groupings, vectors, and such in 12 leads?

I know you said something about having the "basics" down, but different people view the "basics" as different things....no offense intended....

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Posted · Report post

To check for RVI, do a 15 lead. Move V4 to the contralateral position on the right side (V4r) and move V5 and V6 to the posterior (=V8, V9), these three new leads now complete the 15 lead.

As for moving V4-V6 to the right, you can accomplish as much by only moving V4 as it has 90% sesitivity and 90% specificity.

The mention of ST elevation in II, II, and aVf is inaccurate as only ~40% of inferior STEMI involves the right ventricle.

Some hints in a standard 12 lead:

- if there is elevation in V1 only, especially with inferior changes, be suspicious of RVI (proximity to V4r).

- If there is ST depression in V1,V2, be alert it may be reciprocal changes from V8,V9.

Clinically, there is a triad that is common with RVI, this is hypotension, JVD and dry lung sounds, signs common with right heart failure.

As for the comment of treat the patient and not the monitor, that is horrible advice. STEMI is one clinical acumen that is quite definitive with specificity. How else would we give tNK if not for a positive 12 lead in addition to history and clinical findings?

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Posted · Report post

As for moving V4-V6 to the right, you can accomplish as much by only moving V4 as it has 90% sesitivity and 90% specificity.

Thats a very specific staement.

Do you have a reference?

Not that I disagree...just want to be "solid"....

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Posted · Report post

Yeah I think those numbers are a bit fudged. ...Either that or they need to be qualified. I know that the entire 12 lead is not that sensitive for ACS, so I have a hard time believing that a single lead is such a great indicator of RVI.

What MIGHT be true is IF there is a STEMI on the right side, there is a high chance it will show up in V4R. That much is possible. You still ought to post your source if you are going to quote stats like that though.

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Posted · Report post

I've never understood why just V4R is sufficient. Any other time you need TWO leads to say anything... why is it the right side only needs one?

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Posted · Report post

Here is a good article on Right-sided Infarction. It's a little long, but lot's of info.

http://ccn.aacnjournals.org/cgi/content/full/25/2/52#F3

They also suggest moving all leads, including switching V1 and V2.

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Posted · Report post

You can check out Bob Page's book that he uses to supplament his lecture. It is at http://www.multileadmedics.com/seminarhandouts.htm click the MLM 05 Master link. He explains not only how to read 12 leads, but 15 leads, and the right sided MI.

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Posted · Report post

And don't give Fentanyl to them (MS is contraindicated) without MD's orders... like me and get QA'd........ Bad Fred.... (slaps hand for thinking outside of the box).

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Posted · Report post

I've never understood why just V4R is sufficient. Any other time you need TWO leads to say anything... why is it the right side only needs one?

Provincial ALS standards say RVI indicated by V4R with any TWO of II, III and avF.

According to my book approximately half of inferior MI's have right ventricular involvement and that "right ventricular MI's rarely occur independently on inferior wall MI's." (from Ontario Base Hospital Group ALS Pre-course. I'd check my Bledsoe or ECG book but don't have either at the base tonight.)

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Posted · Report post

Thats a very specific staement.

Do you have a reference?

Not that I disagree...just want to be "solid"....

Specific reference, had to search to find my textbook...

- The 12-Lead ECG In Acute Myocardial Infarction, Tim Phalen pp 42. Mosby Lifeline ISBN 0-8151-6752-0

Supporting reference

- ECG's Made Easy, Second Edition, Barbara Aehlert pp 213. Mosby ISBN 0-323-01432-1

- Sensitivity 70-93%, sensitivity 77-100% ( Chou, T, Knilans TK: Electrocardiography in clinical practice: adult and pediatric, Philadelphia, WB Saunders)

J Lopez-Sendon, I Coma-Canella, S Alcasena, J Seoane, and C Gamallo

To clarify, 40% of inferior MI's involve the right ventricle, but >95% of RVI have inferior involvement. DocHarris, we're saying the same thing.

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Specific reference, had to search to find my textbook...

- The 12-Lead ECG In Acute Myocardial Infarction, Tim Phalen pp 42. Mosby Lifeline ISBN 0-8151-6752-0

Supporting reference

- ECG's Made Easy, Second Edition, Barbara Aehlert pp 213. Mosby ISBN 0-323-01432-1

- Sensitivity 70-93%, sensitivity 77-100% ( Chou, T, Knilans TK: Electrocardiography in clinical practice: adult and pediatric, Philadelphia, WB Saunders)

J Lopez-Sendon, I Coma-Canella, S Alcasena, J Seoane, and C Gamallo

To clarify, 40% of inferior MI's involve the right ventricle, but >95% of RVI have inferior involvement. DocHarris, we're saying the same thing.

Well done. Thanks.

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Posted · Report post

This is a RVI from a call I ran personally. Try clicking it to zoom.

RVI.png

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Posted · Report post

FL_Medic thanks for posting this,

that strip is a good example of where V8,V9 posterior leads would be nice to see. You see T wave inversion in V1 and V1 as well as ST depression in V2. I'd be highly suspicious of posterior involvement.

What is the point? It has evovled from an inferior STEMI to Inerior, posterior and right ventricular infarct. Probably a proximal occlusion of the RCA. These patients have a high mortality rate, respond very poorly to SL nitrates (IV drip only) and an example of why EMT's giving nitro, nitro without a 12 lead and IV are all bad things. Also an example of treating the monitor and not the patient. Yes these patients are few, but these are the ones we can kill if treated improperly.

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Posted · Report post

Another example of one I flew a couple of years ago:

INF.jpg

Take care,

chbare.

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