ECG Rhythms- MIS-C Case Report (9-15.21-2024) - DRAFT

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Review of ECG Rhythms — MIS-C Case Report (9/5/2024):

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What follows below are my first impressions of the ECG rhythms sent to me from the Case Report by Dimah Jarmakani et al — of a 12-year old boy with MIS-C (Multisystem Inflammatory Syndrome in Children).

• For full discussion of the case — CLICK HERE —

ECG Rhythm Overview:

A 12-year-old boy was admitted to our hospital with severe myocardial dysfunction and chaotic rhythm with tachy- and bradycardic arrhythmias. What follows are the ECG tracings of our patient:

• ECGs #1 and #2 were performed on the 2nd and 4th hospital days, respectively — at which time the patient had severe myocardial dysfunction. 
• ECGs #3,4,5,6 were done one week later — at which time the patient began to respond to the medical treatment, with recovery of myocardial function. 

We requested assistance from Dr. Grauer for interpretation of the ECG tracings, This is his response to us:  

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My impressions of representative tracings from this case follow below:

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ECG #1:

Figure-1: ECG #1 is from the 2nd hospital day.

MY Thoughts on ECG #1:

This clearly is a challenging series of arrhythmias — obtained from this acutely ill 12-year old boy with MIS-C:

• I put limb leads and chest leads from this first tracing togeter (these tracings were sequentially recorded). Note that this tracing was recorded at half standardization. 
• The rhythm is highly variable. The RED arrow looks like a sinus P wave in front of beat #2. We really do not see more sinus P waves in this ECG #1 — but having glanced ahead at ECG #2, there clearly are sinus-appearing P waves in this next tracing (below) — so I’ll suppose that the RED arrow in front of beat #2 in ECG #1 is a sinus P wave (or possibly a P wave from another atrial focus).
• Given that this RED arrow P wave is pointed — I think we are seeing the opposite picture under each of the YELLOW arrows! I therefore suspect these YELLOW arrows highlight the location of retrograde conduction from ventricular beats.
• QRS morphology of beats #3,4; 6,7; 9,10; 12,13 and 15 shows marked right axis with an rS in lead I — and qR pattern in leads III,aVF.
• Unfortunately — we do not know for certain which beats in the limb leads correspond to which beats in the chest leads — but my guess is that beats #3,4; 6,7; 9,10; 12,13 and 15 with LPHB-like conduction — correspond to the RBBB-like beats in lead V1 of the chest leads. These beats are very wide and not preceded by P waves — so I think these are all PVCs (with a bunch of ventricular couplets) and with the YELLOW-arrow retrograde conduction. RBBB-LPHB-like conduction suggest they may be fascicular beats from the left anterior hemifascicle (although the QRS is wider than fascicular beats usually are).
• In the chest leads of ECG #1 — we also see a LBBB-like etiology for beats #6 and 13 in the chest leads (and perhaps for beats #16,17 in the limb leads). It is hard to say if these are PVCs from another ventricular focus (though their close resemblance to LBBB conduction to me suggests they are supraventricular with aberration.
• I think the BLUE arrows in ECG #1 represent conducted beats from a different atrial focus (ie, negative or not well seen in lead II — but better seen in other leads).
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• BOTTOM LINE — I do not think any of the above details really matter clinically … As you say — the rhythm is chaotic — but not necessarily unexpected given the history of a sick, symptomatic 10-year with severe dilated cardiomyopathy … I’d guess this is sinus rhythm, perhaps with a wandering atrial pacemaker and very frequent ventricular ectopy with multiple couplets. It is not quite MAT — because pure MAT should show a different-shape P wave with every beat, and we don’t quite have that. That said — in my experience, there is a spectrum of disorders with sinus rhythm and PACs at one end — and true MAT at the other end. This rhythm is somewhere in between.

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ECG #2:

Figure-2: ECG #2 is from the 4th hospital day.

Figure-1: I've - ECG-1

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ECG #2 — I again put both pieces together. I’m not quite sure when ECG #2 was done with respect to ECG #1 — nor whether clinical circumstances were different — but this ECG looks VERY different than ECG #1.

RED arrows show what looks to be sinus P waves that are HUGE !!!! = consistent with RAA (which is consistent with this patient’s underlying heart disease. Perhaps the patient has pulmonary hypertension and/or tricuspid regurgitation?

After 2 sinus beats — we see junctional escape at a SLOW escape rate — followed by 2 more sinus beats, and then 2 slow junctional escape beats.

As you suspect — this could reflect SSS ( = Sick Sinus Syndrome) — with need to rule out effect from rate-slowing medication and/or something potentially “fixable” (ie, hypoxemia).

I suspect BEST treatment for these rhythm disturbances is correction of this patient’s underlying heart disease — but that of course is easier said than done …. In the meantime, a pacemaker may be needed.

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ECG #3:

Figure-3: ECG #3 — obtained 1 week later during recovery.

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ECG 3: (HAS 4 tracings):

I am glad your patient is getting a little better. It became difficult to know which tracing was which — so I am placing below what I think are the 4 new tracings. Some of the leads are not labeled — and I don’t know if any 2 make up a complete ECG — but clinically, that really isn’t important since your patient has heart failure from cardiomyopathy and NOT and acute infarction. Whether there is a component of myocarditis is another question …

So I’ll put the 4 tracings I see below with my thoughts. Overall — it DOES look like the patient may be a little better — though still with a chaotic rhythm. There definitel are periods of bradycardia (so pacing may be needed for that). There is an underlying sinus rhythm — with the “theme” being LOTS of ectopics including many different PAC shapes (therefore multiple PAC sites) and some PVCs.

Overall — I think this rhythm “acts” like MAT. By strict definition — each P wave should change in shape with “true MAT” — and that does not quite happen, since there are periods of sinus rhythm. But as I think I mentioned earlier — there is a “spectrum” of supraventricular arrhythmias — and sinus rhythm with lots of different looking PACs as we see here “acts” clinically like MAT. Typically — this may be cause by a very “sick” patient (as is the case for your patient) and/or hypoxemia, electrolyte disorders, heart failure, etc.

BOTTOM LINE — It’s hard to be sure of every single beat — but this is not important. It is the “theme” that counts — which as I describe above, seems to be “acting clinically” like MAT + PVCs — for which best treatment is support and to do the best you can with the patient’s heart failure. Hope this helps — :)

ECG-3 — I see sinus bradycardia and arrhythmia. Beat #4 is a PAC (Note that the P looks different in lead aVL) — and then beat #5 is junctional escape (the sinus P in front of beat 5 has a PR too short to conduct!)

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ECG #4:

Figure-4: ECG-4 — obtained 1 week later during recovery. 

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ECG-4 — I see sinus rhythm for beats #1,2. Beats #3 and 6 look like PVCs. Since the QRS is different and we see retrograde P waves — I think beats #4,5,9,11,13,15,17 are PVCs. The other beats are PACs with different-looking P waves. The fixed coupling for beats #4,5,9,11,13,15,17 supports these being PVCs.

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ECG #5:

Figure-5: ECG-5 — obtained 1 week later during recovery.

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ECG-5 — Now that we know that the tall, pointed P-Pulmonale P waves in lead II are the sinus beats — we can identify the P waves in front of beats #2,6-thru-9 as being sinus P waves. Once again — the P in front of #6 is too short to conduct, so this is junctional escape. After beat #9 — we see the same thing that we saw in ECG #1 ...

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ECG #6:

Figure-6: ECG-6 — obtained 1 week later during recovery.

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ECG-6 — I see sinus brady until the ?. I cannot tell for certain if the “dip” under the BLUE line is a PAC.

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Figure-1: I've