Right Sided MI - How Do I Tell The Difference

[spenac]

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 .

[wrmedic82]

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

[scott33]

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...

Edited April 22, 2009 by scott33

[WolfmanHarris]

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 April 22, 2009 by DocHarris

[ERDoc]

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.

[Ecnalubma08]

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

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

[fiznat]

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 April 22, 2009 by fiznat

[Ecnalubma08]

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

~Ec

[scott33]

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

[FL_Medic]

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.