Right Ventricular Infarction – Part 3

Let’s take a look at another case.

This was one of the first ECGs ever transmitted to my local receiving hospital on the Lifenet Receiving Station. It was definitely the first STEMI.

The data quality of the first 12 lead ECG wasn’t the greatest. This is the second ECG, with lead V4 in the position of V4R.


Unfortunately, I can’t seem to locate the details of this case. All I remember is that it was a male patient with chest pain.

This is an interesting ECG for several reasons.

There is ST segment elevation in leads II, III, and aVF which suggests acute inferior STEMI. You can also make out ST segment elevation in leads V5 and V6.

But where are the reciprocal changes? Normally we’d expect to see something in leads I and aVL. In this case, we don’t even have so much as a flattening of the ST segment.

Very unusual indeed!

The only places I can see ECG changes that could be construed as reciprocal changes are in leads aVR and V1.

Is this a STEMI? I wouldn’t blame you if you gave serious consideration to another diagnosis like pericarditis.

It is a STEMI.

Let’s look at lead V4R. Do you see ST segment elevation?


In fact, there appears to be about 1 mm of ST segment depression.

Is there right ventricular involvement?


The culprit artery isn’t even the RCA. It’s the circumflex (LCX).

Take a look at the image to the right from an editorial in the New England Journal of Medicine by HJ Wellens.

You will note that lead V4R in this case looks almost identical to the third example, which indicates occlusion of the circumflex artery.

When I contacted the director of cardiovascular services at the hospital, he confirmed that the circumflex was 100% occluded.

If you remember your coronary anatomy from Part 1, it’s the right coronary artery (RCA) that typically supplies the right atrium and right ventricle before reaching the inferior wall of the left ventricle.

In a minority of patients, the circumflex (LCX) supplies the inferior wall of the left ventricle. Occlusion of this artery generally does not threaten the right ventricle.

So what have we learned? Is it always necessary to check the right sided precordial leads in the setting of acute inferior STEMI? Or at least lead V4R? It certainly isn’t going to hurt. I won’t discourage it.

Consider this comment left by Shaggy in Part 2.

I work in a busy ED and one day the medics brought in a hypotenisive patient with an inferior wall MI on their 12 lead. I asked the attending if she wanted me to do a 12 lead with V4R. Her answer which I heard from others was if it is inferior and hypotensive, consider it right sided and treat as such. However, after reading this post, I see the importance of checking the right side on a normotensive patient with an inferior MI. I am glad you are around. I just wish I didn’t have to keep reviewing your posts.

I tend to agree with the attending. I would simply include patients who are technically normotensive but on the low side of “normal” especially if they are bradycardic or “shocky” in appearance!

SoCal Medic alluded to another trick in a comment he left for Part 1.

I have been taught two different ways, the first by obtaining V4R and evaluating that for ST Segment changes and the second by comparing Lead II to Lead III.

You will notice that in Part 2, the ST-segment elevation is maximal in lead III over lead II (STE III > STE II). An examination of lead V4R confirms right ventricular involvement.

In this case, ST-segment elevation is maximal in lead II over lead III (STE II > STE III). An examination of lead V4R confirms that there is not right ventricular involvement.

Is it really that simple? Not exactly. STE III > STE II confirms that the culprit artery is the RCA. From there, you should suspect the possibility of RV infarction and treat accordingly. But it does not confirm right ventricular infarction. There is a study forthcoming from Stephen Smith, M.D. on this very topic.

Consider Eskola et al. How to Use ECG for Decision Support in the Catheterization Laboratory – Cases With Inferior ST Elevation Myocardial Infarction. Journal of Electrocardiography Vol 37 No. 4 October 2004.


See also:

Right ventricular infarction – Part 1

Right ventricular infarction – Part 2

Right ventricular infarction – Part 3

Further reading:

Acute Inferior STEMI, Right Ventricular Infarction, and Cardiac Arrest


  • Tazambo says:

    Hi Tom,I just noticed that your profile pictured changed again, that’s 2 new ones in as many weeks, isn’t it?I should really post my photo, it nice to see who’s actually posting.RegardsDave

  • Tom B says:

    Hi Dave,It’s 3 if you include the South Park icon I created at South Park Studio.I took it down after a couple of hours because it didn’t seem professional enough. :)I had the most recent picture taken yesterday for an interview I did with the EP Lab Digest.It should be published in the March 2009 issue.Tom

  • qatardad says:

    The simple rule I always teach is this:1. Any suprapubic complaint gets a routine 12 lead.2. Any inferior MI gets a V4R3. Any inferior MI gets fluid for Frank-Starling priming and we hold off on NTG and MS, or do a careful trial after a bolus (as you described) but obviously go ahead with ASA. Nice blog, BTW. I run paramedicine.com.Marc

  • Anonymous says:

    Hi Tom.Do you give boulus fluid, and hold in with nitro, to all pt with right ventricular infarction, even if they are normotensive ?Sorry for my bad english. /Jenny. Sweden.

  • Tom B says:

    qatardad (Marc) – Thanks for the comment! Sorry I missed it.Tom

  • Tom B says:

    Jenny – If the BP is on the low side of normal with inferior STEMI then I go ahead with a fluid bolus.At the very least I obtain IV access before the first trial dose of NTG!Tom

  • Anonymous says:

    How about posterior involment in RV infarction ? Should ST depression in V1-v3(v4) be a "heads up" for RV involment as well in as inferior infarctions? The RCA supports the posterior wall to, doesnt it ?Thanks again for a really nice blogg. Keep it up./Rookie

  • Tom B says:

    Rookie – The RCA often supplies the posterior wall through the posterior descending artery, but that's a distal branch of the RCA.It's a proximal occlusion of the RCA we're concerned with! I always look for the tell-tale ST segment depression in the right precordial leads with inferior ST elevation, but it's not my main tip-off that I'm dealing with RVI! I still feel the best evidence is STE in lead III > STE in lead II, although STE in V4R is also part of the puzzle (and let's not forget the physical exam).Tom

  • Hillis says:

    I know the article was posted around year but just i'd like to thanke you Tom for your great work .. I should admit in each case am learning and revising alot of information that i've unfortunately missed and still learning !!. The interpretation of ECG is so tricky !!Thanke you so much

  • Tom B says:

    My pleasure, Dr. Hillis! Thank you for reading my blog!


  • muataz says:

    thank u Tom its really informative

  • Bill MacPherson says:

    This was excellent and this is what we need for more learning for all of us. When we work together as a team with our patients wellbeing in our insterest the outcome will be all positive. I have worked as an ED nurse for 25 years now I’m in med school and believe me as a physician if you don’t listen to the paramedics story and the nurses you are in BIG TROUBLE work together and respect all and learn two heads are better then on
    Thanks Bill (Canada)

  • Tony says:

    Thanks for posting this review. I will certainly use the information for my students and my own practice in the field.

  • Steve Smith says:

    This quote is incomplete because it does not interpret when STE in II is > than STE in lead III.

    “An examination of lead V4R confirms that there is not right ventricular involvement. Is it really that simple? Actually, it is.”

    STE in II > STE in III is good evidence of circ occlusion and thus has good NPV for RVMI. However, STE in II > III implies RCA occlusion but NOT RVMI. It makes RV MI possible because the RCA is involved, but not at all necessary. Thus, it has a poor PPV. STE in V1 has a good PPV, but if there is any ST depression in V2 or V3, a poor NPV.

  • Sean says:

    The one thing that would make this the perfect post is a video on 15 lead placement. Otherwise you just cleared up a bunch of issues for me. Thanks

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