ECG Blog #452 — Is this Wide QRS Rhythm VT?

The patient whose ECG is shown in Figure-1 — presented with acute dyspnea and hypotension.

QUESTION:

• In Figure-1 — Is the rhythm VT?
•   — How certain are you of your answer?

Figure-1: The initial ECG in today's case. (To improve visualization — I've digitized the original ECG using PMcardio).

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MY Thoughts on the ECG in Figure-1:

Although at first glance, the ECG in Figure-1 appears to be wide — this is a false initial impression! Closer inspection suggests that the QRS complex is actually narrow — and that the reason the QRS appears to be wide, is that the dramatic picture of "Shark Fin" ST Elevation is present!

• I have previously reviewed a number of cases of "Shark Fin" morphology (See ECG Blog #364 — Blog #410 — Blog #265 — among others).

Consider the following in Figure-2 — in which I've labeled today's ECG:

• Look closely in all 12 leads — to see if there are one or more leads that allow you to precisely define the limits of the QRS complex. I've drawn vertical RED lines to highlight these leads. Everything to the right of these RED lines marks the beginning of the ST segment (BLUE arrows in Figure-2) — which shows marked ST elevation in multiple leads!
• Following these RED lines upward — suggests there is ST depression in leads aVL; aVR; V1,V2.
• Sinus P waves are best seen in lead V1. Note that the 4th QRS complex in lead V1 is wider, and preceded by an on-time sinus P wave with a shorter PR interval (PINK arrow P wave in lead V1). The fact that this PR interval is shorter than all other PR intervals in this lead — means that this 4th QRS complex in lead V1 must be a PVC (albeit possibly with some fusion) — because there is not adequate time for this PINK arrow P wave to conduct all the way through the ventricles. This proves that the other 5 beats in lead V1 (that are each preceded by an on-time RED arrow P wave) — are sinus-conducted beats.
• Isn't it easier to appreciate that the 5th colored arrow in lead V1 is a sinus P wave — because of the slightly longer R-R interval that precedes it? (made possible because the 4th QRS complex in this lead is a PVC that occurs before the next sinus-conducted beat would have occurred).
• We call this 4th QRS complex in lead V1 a "late-cycle" PVC (Premature Ventricular Contraction) — because it occurs at a fairly late point in the R-R interval.
• Late-cycle PVCs are also seen in lead II and in lead aVL. In each of these leads — we see an on-time sinus P wave preceding a wider and different-looking QRS complex with a PR interval that is too short to conduct normally — thereby proving that the QRS complexes seen right after these PINK arrow P waves in leads II and aVL are PVCs (albeit possibly with some fusion).
• There is another PVC that occurs immediately after the lead change in lead aVL — but the lead change (vertical black line) blocks our view of the P wave before this beat.

BOTTOM Line:

• Today's patient presented in shock (presumably cardiogenic) — with acute dyspnea, hypotension, and the ECG that is shown in Figure-2.
• This ECG shows marked sinus tachycardia with end-cycle (late-diastolic) PVCs — and with Shark Fin ST elevation in multiple leads. Given the diffuse nature of ST-T wave changes — this ECG picture presumably is the result of acute LAD occlusion (or possibly even LMain occlusion).

Figure-2: I've labeled the initial ECG in today's case.

CASE Follow-Up: 

Unfortunately, my follow-up of today's case is limited. The "good news" — is that this patient did survive!

• Optimal treatment of the patient in today's case would entail recognizing there is sinus tachycardia with marked and diffuse Shark Fin ST elevation — with need for prompt cath and almost certain need for coronary reperfusion with PCI (Percutaneous Coronary Intervention).

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Acknowledgment: My appreciation to Haseeb Raza Naqvi (from Multan, Pakistan) for the case and this tracing.

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ADDENDUM (10/19/2024):

• The Audio Pearl below reviews the concept of "shark fin" ST elevation. 

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ECG Media PEARL #73 (5:40 minutes Audio) — Reviews the concept of "Shark Fin" ST elevation and depression as a sign of extensive acute infarction.

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Related ECG Blog Posts to Today’s Case:

• ECG Blog #185 — My Ps, Qs, 3R System for Rhythm Interpretation.
• ECG Blog #205 — Reviews my Systematic Approach to 12-lead ECG Interpretation.
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• ECG Blog #364 — Blog #410 — Blog #265 — for more examples of Shark Fin Morphology.

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