Similar 3 EKGs. help !

[pchangb]

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Presupposition : All these 3 EKGs correspond to myocardial infarction. No further
information is given.

Question : Discuss whether these are transmural / subendocardial MI and localize
infarcted area.

Note that these all three EKGs clearly have ST depressions in precordial leads.
I have answers (these are from printed material) but don't know details about
these EKGs. I do not provide answers to reduce bias, later I will quote.

My brain aches whenever I see ST segment in a lead - is it by primary infarction ? or is it just a reciprocal change ? How can I differentiate between primary and reciprocal ?

EKG isn't almighty, it does not tell us everything. But we can discuss the probability, ex) "it looks like posterior transmural MI, rather than anterior subendocardial MI"

Ekg-1 :

Ekg-2 :

Ekg-3 :

 

[Packman2003]

My guess would be 1 is an occluded RCA, 2 is subendocardial and 3 is a posterior - maybe a distal occlussion of the circumflex. I don't start med school until August but I have some familiarity with EKGs as a Cardiology Tech and EMT. I just want to play for fun.

1. Inferior elevation with reciprocal left-sided changes would make me think RCA. Pathologic Q waves in inferior leads. I would get a right sided EKG as well if there is time.

2. Mostly depression. Q Waves in septal leads, but no ST elevation that meets STEMI criteria for a complete MI - in fact the only precordial lead that is not depressed is V1.

3. Looking in V1-V3 you have classic signs of posterior MI - most notable is the R wave and depression in V1. The st changes in V6 also supports a circumflex occlusion. A posterior EKG would be useful.

 

[drstar842]

I'm not the best at explaining things which are easier to point out visually, so forgive me in advance if any of the below sends you down a rabbit hole. Generally speaking, the direction of the GREATER deviation should be considered primary, and the direction of the lesser deviation considered secondary or reciprocal. Obviously, like all other things in medicine, there are exceptions. For instance, when there is epicardial injury involving both the inferior and posterior aspects of the left ventricle, the ST segments depression of the posterior involvement in leads V1-V3 may equal or exceed the ST elevation produced by inferior involvement in leads II, III, and aVF. But, other than that exception (and a few other cardiac conditions), if we have an ST elevation on ECG, go with the ST elevation as the primary change. Any depressions seen on EKG are typically reciprocal (obligatory) or secondary consequences from the primary infarction. Remember, the only EKG changes seen with non-Q wave infarctions are T wave inversion and ST segment depression. So, if we only have ST segment depressions on the ECG then we can rule out a transmural infarction (unless posterior infarction which show ST segment depression and tall R waves in the anterior leads without any reciprocal ST elevations in the standard leads). These are my best guesses on the EKGs. I think Packman hit most of the points (great call on ordering R-sided EKG, in fact, it should be performed in all patients presenting with an acute inferior MI in order to look for evidence of RV involvement), but I disagree with his intrepretation of the 2nd EKG.

EKG 1:
Findings
Elevated ST segments in leads II, III, and aVF
ST depressions in leads I, aVL, V2-V6
T-wave inversions leads I, aVL, V4-V6
Deep Q waves in II, III, and aVF
ST depression amplitude I, aVL < ST elevations II, III, and aVF​

Dx
Acute transmural inferior wall infarction due to a complete posterior descending artery occlusion w/ reciprocal ST depression laterally in leads I and aVL
Left-Ventricular subendocardial localized ischemia involving the LCX or LAD
LVH​

EKG 2:
Findings
Elevated ST segments in lead aVR and V1
ST segment depressions in leads I, II, III, avF, avL, V2-V6
T-wave inversions leads I, aVL, V3-V6
Poor R wave progression​

Dx
Acute transmural right ventricular epicardial infarction due to a complete proximal occlusion of the right coronary artery with reciprocal ST depression in almost all other leads. The absence of ST elevation in V2 and V3 rules out an anteroseptal infarction.
Left-Ventricular subendocardial localized ischemia involving the LCX or LAD​

EKG 3:
Findings
Elevated ST segments in aVR, V6
ST depressions in V1-V4
Prominent R waves in V1 and V2 that are greater than the S waves
Q-waves in lead III, lead aVF, and lead II
Q-wave amp - Lead III > Lead aVF > Lead II​

Dx
Acute transmural posterior wall infarction due to a complete LCX occlusion
Old inferior wall infarction demonstrated by a deep Q-wave in lead III (which makes sense considering the inferior wall usually has the same blood supply as the posterior wall)​

 

[josephf1]

ECG 1 - INF, usually if ST elevation in II > III its RCA/PDA dominant and if III > II Cx dominant.

ECG 2 - ST elevation in AVR is a 'soft marker' for triple vessel disease, as is diffuse ST changes, this is a guy I would typically NOT plavix load in the ED until his coronaries got squirted in case of CABG, especially if DM.

ECG 3 - Q waves in III are notoriously bogus, especially if only in III and < .04 msec, often disappear on inspiration in real time ECG monitoring.

 

[drstar842]

ECG 1 - INF, usually if ST elevation in II > III its RCA/PDA dominant and if III > II Cx dominant.

ECG 2 - ST elevation in AVR is a 'soft marker' for triple vessel disease, as is diffuse ST changes, this is a guy I would typically NOT plavix load in the ED until his coronaries got squirted in case of CABG, especially if DM.

ECG 3 - Q waves in III are notoriously bogus, especially if only in III and < .04 msec, often disappear on inspiration in real time ECG monitoring.

I'd have to disagree on your ECG 3 analysis. While a Q wave in lead III or aVR is considered normal, the Q wave present in lead III on this ECG along with the Q waves on lead aVF and lead II (which I left off the findings, but updated) go along with the picture of a "true posterior MI," which usually includes either an ongoing inferior MI or presence of an old inferior MI. Typically, the changes seen on ECG for an acute inferior transmural MI include Q-waves and ST elevations in II, III, and avF with Q waves being the largest in lead III, followed next by lead aVF, and then lead II. After reperfusion, the ST changes return to their isoelectrical state, leaving behind any Q waves that might have been present. This ECG shows a Q wave in III that is greater than the Q wave in aVF which is then greater than the smallest Q wave in lead II. I'm still gonna stick with it being an acute transmural posterior wall infarction due to a complete LCX occlusion with evidence of an old transmural inferior wall infarction from a previous LCX dominant occlusion.

Basically, what I am saying is that I agree with you that Q waves in III are notoriously bogus, but in the context of an acute posterior MI, Q waves also in aVF, and II, and the high association of posterior and inferior wall MIs, well, it'd be worth calling records for old ECGs.

 

[josephf1]

dont know about you but i only see a small q wave in III in ecg 3

 

[Trifling Jester]

1: RCA
2: LM or 3v disease... more likely LM because ST elevation in AVR>V1
3: PDA

 

[pchangb]

I copy the answer for Ekg-1 to this forum.

Ekg-1 :

II,III,aVF : Q-wave, ST elevation
right precordial leads : tall R-waves, ST-segment depression, upright T-waves
So, we get inferior-posterior MI.
lateral leads : ST-segment depression, T-wave inversions. There are 2 possibilities 1) reciprocal change from the acute inferior MI, 2) lateral subendocardial injury. We could not find any abnormality in lateral myocardium.

Answer : inferior-posterior MI

 

[pchangb]

Ekg-2 :
all leads except aVR, V1 : ST depression
aVR, V1 : reciprocal ST elevation
'Widespread ST depression except aVR, V1' + 'ST elevation aVR' means LMCA occlusion/proximal LAD occlusion. aVR>V1 means LMCA occlusion rather than proximal LAD occlusion.
Answer : anterior subendocardial infarction by LMCA occlusion

 

[pchangb]

Ekg-3 :
V1-V4 : ST depression
V6 : ST elevation
In LCX occlusion, posterior injury (V1-V4 : ST depression) + inferior injury (II,III,aVF elevation) is common but posterior injury without any inferior injury is also possible pattern. And ST elevation in V5&#8722;6 is often observed in LCX occlusion. For this patient, posterior ECG leads was additionally done and posterior leads showed ST elevation.
Answer : posterior MI by LCX occlusion.

Thank you for all replies ! All of you are great !

 

[Packman2003]

3 for 3