VF arrest at home, no memory of chest pain. Angiography non-diagnostic. Does this patient need an ICD? You need all the ECGs to know for sure.

Written by Willy Frick

A man in his 50s was at home with his family when they heard a thud and rushed into the room to find him unconscious with agonal respirations. His daughter immediately started CPR and another family member called EMS. When EMS arrived the patient was in ventricular fibrillation. They shocked him twice before return of spontaneous circulation. He was intubated in the field and sedated upon arrival at the hospital. Here is his presenting ECG:

ECG 1, t = 0

What do you think?

This was interpreted by the treating clinicians as not showing any evidence of ischemia. At first glance, it is easy to dismiss leads V1-V3 due to baseline wander. But close inspection reveals subtle terminal TWI in V4. Once you notice this, that you can appreciate biphasic T waves in V2 and V3 beneath the artifact. In context of VF arrest, this is extremely suspicious for reperfused LAD OMI.

Initial hsTnI was 384 ng/L. The patient was treated as possible NSTEMI and underwent coronary angiography about 4 hours after presentation. The report describes a 60% proximal LAD lesion with TIMI 3 flow. (TIMI 3 means the rate of passage of dye through the coronary artery is normal by angiography.) Lesions less than 70% are generally considered to be non-flow limiting. Given the presentation, the cardiologist stented the vessel and the patient returned to the ICU for ongoing critical care. Two subsequent troponins were down trending. Echocardiogram showed LVEF 66% with normal wall motion and normal diastolic function.

Within a few days, the patient was extubated and was neurologically intact. However, he did not remember much from the day of the arrest. He did not remember whether he had experienced any chest pain. At his family's request, he was transferred to a hospital closer to his home to continue care. He was admitted to cardiology. His transfer packet included notes, labs, cath report, and ECG reports, but no actual ECG images. His ECG at the accepting facility is shown below:

Accepting facility ECG

The team reviewed his angiography films with an interventionalist and thought they were suspicious for plaque rupture in LAD, but they were not confident. Stated differently, the differential diagnosis for the presenting syndrome was either ventricular fibrillation due to acute coronary syndrome, or idiopathic ventricular fibrillation and bystander stable CAD. This is a critically important determination because of the 2017 AHA/ACC/HRS Guidelines for Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death. See the following management algorithm:

In other words, if this arrest is determined to have been due to acute coronary syndrome, the patient can be monitored without the immediate need for ICD implantation. On the other hand, if this was idiopathic VF and the interventionalist stented a stable moderate LAD lesion (remember, 60% is considered non-obstructive), the patient should have ICD implantation prior to discharge. Remember that hsTnI was 384 ng/L on presentation and trended down, relatively unimpressive.

They consulted EP for evaluation for ICD. The electrophysiologist is a reader of Dr. Smith's ECG Blog. When he reviewed the case, he only had access to the accepting facility ECG. He did not have access to ECG 1. In context, he thought it was suspicious but not diagnostic for reperfused LAD OMI. He contacted the referring facility and asked for copies of all the ECGs they had obtained. Here they are in sequence:

ECG 1, t = 0

ECG 2, t + 4 h

ECG 3, t + 24 h

ECG 4, t + 48 h

ECG 5, t + 72 h

In sequence and in clinical context, the ECGs tell a convincing story. The patient suffered LAD OMI at home and secondary VF arrest. By the time he arrived at the hospital, he already had spontaneous reperfusion, evident in the subtle TWI in the anterior leads in ECG 1. Non-emergent angiography showed an underwhelming "non-obstructive" 60% LAD lesion due to robust spontaneous recanalization, and over the next few days he had progressive deepening of his T waves followed by the beginning of return to normal. The relatively low troponin value fits exactly with brief LAD OMI.

By themselves (not evaluating the progression), the Queen of Hearts AI system diagnosed ECG 2 as Not OMI, and ECGs 3-5 as OMI (she is unable to compare serial ECGs even though this would make it much easier for her.)

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The patient was discharged without an ICD, in accordance with guidelines.

Learning points:

• Chart review is an under-appreciated, extremely high value practice. The electrophysiologist in this case saved the patient from getting an ICD simply by taking the time to gather and review existing medical data.

• OMI can be extremely brief with spontaneous recanalization and only mild troponin elevation. Angiography tells you the state of the vessel at that moment in time. Putting ECG in clinical context can tell you what the vessel looked like before presentation!

• Angiography can be misleading and must always be understood in clinical context.

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MY Comment, by KEN GRAUER, MD (6/23/2024):

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The beauty of Dr. Frick's presentation in today's case is its simplicity in conveying a critically important finding affecting the outcome of this patient.

• Simply by correlating the history of cardiac arrest with serial ECGs recorded after the event — it became obvious that the 60% lesion on cardiac cath, despite its surprisingly good TIMI 3 flow — was indeed the "culprit" artery that had spontaneously reperfused after the event.
• As per Dr. Frick — "Angiography can be misleading — and must always be understood in clinical context".

The parallels between today's case and Wellens' Syndrome are important to recognize. The principal difference between these entities, is that instead of a cardiac arrest being the event that suggests transient LAD occlusion — with Wellens’ Syndrome, it is the history of a recent episode of chest pain that has now resolved at the time we see an ECG showing signs of LAD reperfusion that tells us the LAD has recently occluded, but has now reopened.

• Clinical deduction by correlation of history with serial ECGs in Wellens’ Syndrome is similar to the process described by Dr. Frick in today’s case. With Wellens’ Syndrome — recognition of this entity is essential for expediting cardiac cath with PCI because of an otherwise excessively high risk that the recently opened “culprit” vessel may at any time reocclude.
• Yet just as initially occurred in today’s case — failure to correlate serial ECGs with the history almost led to misinterpretation of cardiac cath findings — until the EP cardiologist was consulted, and knew to go back to the basics of gathering all tracings for serial review.

The above said — it may prove insightful to take another look at the Wellens' Syndrome case instantly recognized by Dr. Smith in the August 12, 2022 post in Dr. Smith’s ECG Blog.

• The merit of reviewing this August 12, 2022 case — is our need as emergency providers to immediately recognize signs of cardiac reperfusion — that by simply correlating ECG findings with the history — we can know within seconds the pathophysiology involved, and the current state of the “culprit” vessel.
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• I find it amazing how application of the simply stated Learning Points by Dr. Frick at the end of today’s case can tell so much — if we simply stop to look and listen.