A 50-something man with Chest pain at triage

A 50-something male presented to triage with chest pain for one day.

An ECG was recorded quickly before any further history or physical exam:

What do you think?

When I saw this (presented at a conference), I immediately thought it looked like Thype 1 Brugada phenocopy (in other words, Type 1 Brugada ECG pattern).  There is an rSR' in lead V1 without any spike of the R'-wave.  The downsloping STE starts immediately from the peak, leading to an inverted T-wave.  Lead V2 also has downsloping STE with an inverted T-wave.

There is also some STE in aVL, with reciprocal STD in inferior leads, highly suggestive of OMI.  This is unusual for Brugada and so one must be very careful not to brush it off.  It still could all be due to a proximal LAD Occlusion.

In spite of the unusual appearance of aVL and inferior leads, I still thoght it looked like Brugada, but further investigation is warranted:

Case continued:

Further history revealed cough and shortness of breath.  The temperature was 39.5 C.  A Chest X-ray showed infiltrates.  Thus, another etiology of chest pain is found, and the fever suggests "fever-induced Brugada."  The physician in charge quickly realized all this and did not activate the cath lab.

More ECGs were recorded:

18 minutes:

The Queen of Hearts was fooled, but with low confidence:

The initial troponin returned at less than 3 ng/L.

2 hours:

Continued Brugada Phenocopy

Again, V1 and V2 have Type 1 Brugada pattern (see criteria for Type 1 below)

To determine whether it is indeed Brugada or not, it is important to determine whether the QRS is actually prolonged or not.

If the QRS is prolonged, then the differential includes:
1. Hyperkalemia
2. Drug toxicity, especially diphenhydramine, which has sodium channel blocking effects, and also anticholinergic effects which may result in sinus tachycardia, hyperthermia, delirium, and dry skin.
----Other drugs with sodium channel blockade: Tricyclic antidepressants.  They result in a large R-wave in aVR, but also usually have a wider QRS.
----Other sodium channel blockers, such as flecainide or cocaine.

However, if the QRS is not prolonged, then Brugada is likely, and in this case, Brugada uncovered by fever is the likely culprit.

Criteria for Type 1 Morphology:
1. R'-wave of at least 2 mm in V1 or V2
2. But no distinct R'-wave because the ST segment takes off at an angle from the peak
3. The ST segment is convex upward ("coved"). [They use terminology of "concave downward"]
4. The peak at the high takeoff does not correspond with the J-point. It is BEFORE the J-point, as measured in other leads (e.g. lead II across the bottom).  See this demonstration.
5. Gradual downsloping of ST segment such that at 40 ms after the takeoff, the decrease in amplitude is less than 4 mm (in this example, it is less than 1 mm).  In normal RBBB, the decrease in amplitude is much greater (see this example).
6. ST is followed by a symmetrically negative T-wave
7. "The duration of QRS is longer than in RBBB," and "there is a mismatch between V1 and V6." This criterion is perplexing and not well explained.
8. The downsloping should be such that the Corrado index is greater than 1.0 (see example above), which ensures that there is enough downsloping of the STE.
Corrado index is the ratio: [ST elevation at the J-point] divided by [ST elevation at 80 ms after the J-point].  A flat ST segment will have a Corrado index greater than 1.

See here for more detail, especially on Type 2 Brugada: 

Is this Type 2 Brugada syndrome/ECG pattern?

Case continued:

Next AM:

Continued Type 1 Brugada phenocopy

Day 2:

Now it has Type 2 Brugada Morphology!

See this post to learn more about Type 2 Brugada and its morphology:

Is this Type 2 Brugada syndrome/ECG pattern?

There is a score called the "Shanghai score" (links to mdcalc online calculator) which calculates risk of Brugada.  It is to be used when there is clinical suspicion of Brugada syndrome based on the ECG findings, and is based on:

1. ECG

1.a. Type 2 or 3 pattern that converts wth provocative drug challenge. +2

1.b. Fever induced Type 1 pattern: +3

1.c. Spontaneous Type 1 pattern: +3.5

2. Clinical History

2.a. of atrial fib/flutter at age less than 30: +0.5

2.b. syncope of unclear etiology: +1

2.c. Suspected arrhythmic syncope: +2

2.d. Nocturnal agonal respirations: +2

2.e. Unexplained cardiac arrest or documented VF/polymorphic VT: +3

3. Family History

3.a. None: 0

3.b-d. Unexplained sudden cardiac death (3 categories) (+0.5 - +2)

4. Genetic test result

For this patient, he gets 3 points for fever induced Brugada and zero points for other categories, for a total of 3, which results in "Possible Brugada Syndrome"

Course: The patient's pneumonia was treated and improved.  He was hemodynamically stable for discharge. He was advised to aggressively manage hyperpyrexia in the future and avoiding sodium channel blocking agents. 

 

Here are more cases of Fever-induced Brugada:

--Hyperthermia and ST Elevation 

    -- The syndrome of Brugada and Fever was discussed at length

--A Patient with Syncope 

     -- a very subtle case of syncope due to Brugada that was missed on the first presentation and not diagnosed until he had recurrent syncope 3 years later.

--Syncope and ST Segment Elevation. And another finding. How well does the computer interpretation perform? 

     -- in this case, the computer diagnosed STEMI but the patient had Fever with Brugada

--A young F is hyperthermic, delirious, and dry: Fever-induced Brugada? Diphenhydramine toxicity? Tricyclic?

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MY Comment, by KEN GRAUER, MD (1/13/2025):

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Today's case highlights a number of KEY points:

• Point #1: Our need for comfort in recognizing Brugada Phenocopy (as emphasized in the July 22, 2023 post of Dr. Smith's ECG Blog — as well as in the May 5, 2022 post — the November 25, 2022 post — among many others).
• Point #2: Our need to remember the common causes of Brugada Phenocopy.
• Point #3: Phenocopy should only be diagnosed after ruling out other causes of the abnormal ECG.
• Point #4: Awareness of the history is critical for distinction between Brugada Syndrome vs Phenocopy.

Applying these Points to Today's Case:

Although Dr. Smith instantly recognized the Brugada-1 ECG pattern in leads V1,V2 of today's initial ECG — there were other essential findings in this tracing and in this case:

• As noted by Dr. Smith — There is coved ST elevation in lead aVL, in association with reciprocal ST depression in each of the inferior leads.
• There is subtle-but-real ST depression in leads V5,V6.
• Despite the typical Brugada-1 appearance in lead V1 in the initial ECG (with the framework of this Brugada-1 pattern continuing in lead V2) — the ST segment in lead V2 remains elevated by 3+ mm. for a longer duration than is generally seen with simple Brugada Phenocopy.
• The presenting complaint noted at Triage was, "a 50yo man with chest pain!" Subsequent history in today's case clarified the situation (in that this patient had dyspnea, cough and a high fever as the result of pneumonia) — but that information was not known at the time the initial ECG was reviewed.
• Among potential conditions that may produce Brugada Phenocopy are infarction and ischemia. As a result — today's initial ECG could be consistent with Brugada Phenocopy that is secondary to an acute OMI.

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Brugada ECG Patterns:

No matter how many times I have seen Brugada-1 and Brugada-2 ECG patterns — I still find myself referring back to the images in Figure-1:

Figure-1: Review of ECG Patterns in Brugada Syndrome (adapted from Brugada et al in JACC: Vol. 72; Issue 9; 2018) — A) Brugada-1 ECG pattern, showing coved ST-segment elevation ≥2 mm in ≥1 right precordial lead, followed by a negative T-wave. — B) Brugada-2 ECG pattern (the “Saddle-back” pattern) — showing concave-up ST-segment elevation ≥0.5 mm (generally ≥2 mm) in ≥1 right precordial lead, followed by a positive T-wave. — C) Additional criteria for diagnosis of a Brugada-2 ECG pattern (TOP: the ß-angle; BOTTOM: A Brugada-2 pattern is present if 5 mm down from the maximum r’ rise point — the base of the triangle formed is ≥4).

Regarding BRUGADA Syndrome vs Phenocopy:

• By way of review — a Brugada Type-1 ECG pattern is diagnosed by the finding of ST elevation of ≥2 mm in one or more right-sided precordial leads (ie, V1, V2, V3) — followed by an r’ wave and a coved or straight ST segment — in which the ST segment crosses the isoelectric line and ends in a negative T wave (See Panel A in Figure-1).
• A Brugada-1 pattern may either be observed spontaneously (with leads V1 and/or V2 positioned normally — or positioned 1 or 2 interspaces higher than usual) — or — a Brugada-1 pattern may be observed on provocative drug testing after IV administration of a sodium-channel blocking agent such as ajmaline, flecainide or procainamide.
• NOTE: Although Panel A in Figure-1 illustrates the typical appearance of a Brugada-1 ECG pattern — there are variations on this "theme". The common denominator for Brugada-1 ECG patterns is ST elevation that shouldn't be there in ≥1 right precordial leads — followed by a rapid ST segment downslope into a negative T wave. The elevated ST segment often manifests a sharp descent — but at times, it may have a more rounded appearance (as it does in today's case).
• 
  
• Panel B in Figure-1 illustrates the Brugada Type-2 or “Saddle-back” ECG pattern. This pattern may be suggestive — but is not diagnostic of Brugada Syndrome. Depending on the presence or absence of other clinical factors — a Brugada-2 ECG pattern by itself (ie, without a Brugada-1 pattern) — may not be clinically significant.

Common Causes of Brugada Phenocopy: 
Among conditions other than Brugada Syndrome that may temporarily produce a Brugada-1 ECG pattern are:

• Acute febrile illness.
• Variations in autonomic tone (as may occur with syncope). 
• Hypothermia. 
• Ischemia or infarction.
• Cardiac arrest. 
• Electrolyte disorders (especially hyperkalemia — but also hypokalemia or hyponatremia). 
• Certain medications.
• Other conditions not listed above ...

Patients with such conditions that may transiently mimic the ECG findings of a Brugada-1 pattern are said to have Brugada Phenocopy. 

• The importance of recognizing Phenocopy — is that correction of the underlying condition may result in resolution of the Brugada-1 ECG pattern (with a far better prognosis compared to patients with true Brugada Syndrome).
• The 2 most common precipitants of Brugada Phenocopy that we've seen on Dr. Smith's ECG Blog have been: i) Acute febrile illness; and, ii) Hyperkalemia. That said — today's case illustrates the importance of remembering that acute infarction or ischemia may also produce this pattern.
• IF it is clinically clear that the transient appearance of a Brugada-1 ECG pattern was "pure" Phenocopy (and solely due to an acute illness or condition that was easily corrected) — then no additional evaluation may be needed. If instead — the patient has other risk factors, a positive family history, or other clinical concerns — then referral for provocative testing with a sodium channel blocking agent can be undertaken to rule out Brugada Syndrome.