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The Road to Diagnosis: ECGs, Tests, and Scores

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Brugada syndrome is diagnosed by identifying a Type 1 coved pattern on an ECG. If resting ECGs are inconclusive, doctors use provocation tests with specific medications and the Shanghai Scoring System to make a definitive diagnosis and rule out temporary mimics known as phenocopies.

Key Takeaways

  • • The Type 1 'coved' ECG pattern is the primary hallmark used to diagnose Brugada syndrome.
  • • Provocation tests using medications like ajmaline or flecainide can unmask hidden Brugada patterns if a resting ECG is unclear.
  • • Doctors use the Shanghai Scoring System to combine ECG, clinical, family, and genetic factors into a definitive diagnosis.
  • • Brugada phenocopies are temporary conditions that mimic the Brugada ECG pattern but resolve completely once the underlying cause is treated.

Diagnosing Brugada syndrome (BrS) is often like solving a puzzle. Because the electrical pattern can come and go, doctors use several specialized tools and scoring systems to determine if you have the condition or if your ECG is simply mimicking it [1].

Understanding ECG Patterns

The primary tool for diagnosis is the Electrocardiogram (ECG), which records your heart’s electrical activity. There are two main patterns doctors look for:

  • Type 1 (The “Coved” Pattern): This is the diagnostic hallmark. It looks like a steep hill (ST-segment elevation of ≥2\ge 2 mm) followed by a downward slope and a negative T-wave in the right precordial leads (V1-V3) [2][3]. If this appears on its own (spontaneously), it carries significant diagnostic weight [4].
  • Type 2 & 3 (The “Saddleback” Pattern): These look more like a valley or a horse’s saddle, often with less elevation (≤2\le 2 mm) [5]. While they raise suspicion, they are not enough for a definitive diagnosis on their own and are generally associated with a lower risk [6].

High-ICS Leads

Sometimes the Brugada pattern is “hidden” in the standard chest lead positions. To find it, doctors may perform a High-ICS (Intercostal Space) ECG. They move the V1 and V2 stickers up one or two rib spaces higher on your chest [7]. This higher view of the heart can increase the chances of uncovering a hidden Type 1 pattern, improving diagnostic accuracy [7].

Provocation Testing

If your resting ECG is inconclusive (like a Type 2) but your doctor still suspects BrS, they may suggest a Provocation Test (also called a pharmacological drug challenge) [8].

  1. How it works: While you are closely monitored in a clinical setting, you receive an infusion or dose of a sodium channel blocker, such as ajmaline or flecainide [8][9].
  2. The Goal: These drugs temporarily stress your heart’s electrical “gates.” In someone with Brugada syndrome, the drug will unmask a Type 1 pattern on the ECG [8][10].

The Shanghai Brugada Scoring System

Because no single test is perfect, doctors use the Shanghai Brugada Scoring System to look at the “big picture.” Points are awarded based on a combination of factors [11][12]:

  • ECG Findings: Was the Type 1 pattern spontaneous or drug-induced?
  • Clinical History: Have you fainted (syncope) or had a cardiac arrest?
  • Family History: Has a relative been diagnosed or died young?
  • Genetics: Do you have a mutation in the SCN5A gene?

A total score of ≥3.5\ge 3.5 points indicates a “probable or definite” diagnosis of Brugada syndrome, while 2-3 points means it is “possible,” and less than 2 is non-diagnostic [11].

Brugada Phenocopies: The Great Mimics

Not everything that looks like Brugada on an ECG is actually Brugada syndrome. A Brugada Phenocopy (BrP) is an ECG pattern that is identical to true BrS but is caused by a temporary, reversible condition [13][14]. Common causes of phenocopies include [15][16]:

  • Severe electrolyte disturbances (such as severe hypokalemia/low potassium) [16]
  • Metabolic disorders like extreme acidosis [13]
  • Drug toxicity (such as tricyclic antidepressant overdoses or supra-therapeutic phenytoin levels) [15][17]
  • Acute illnesses like pericarditis [18]

The key difference is that a phenocopy goes away entirely once the underlying cause is corrected, whereas true Brugada syndrome is a lifelong genetic susceptibility [14][16]. Identifying a phenocopy is vital because it prevents you from being diagnosed with a genetic disease you don’t have [19].

Frequently Asked Questions

What does a Type 1 Brugada ECG pattern look like?
The Type 1 pattern is the main diagnostic hallmark for Brugada syndrome. It looks like a steep hill, called a coved pattern, on the electrocardiogram. If this pattern appears spontaneously, it carries significant diagnostic weight.
Why would I need a Brugada provocation test?
A provocation test is used if your resting ECG is inconclusive but your doctor still suspects Brugada syndrome. While closely monitored, you are given a medication like ajmaline or flecainide to temporarily stress the heart's electrical gates and see if it unmasks a hidden Type 1 pattern.
What is the Shanghai Brugada Score?
The Shanghai Brugada Scoring System helps doctors evaluate your overall risk and confirm a diagnosis. It assigns points based on your ECG findings, clinical history, family history, and genetic test results. A total score of 3.5 or higher indicates a probable or definite diagnosis.
What is the difference between Brugada syndrome and a Brugada phenocopy?
A Brugada phenocopy is an ECG pattern that looks exactly like Brugada syndrome but is caused by a temporary issue, such as an electrolyte imbalance, fever, or medication side effect. Unlike true Brugada syndrome, the ECG pattern goes away entirely once the underlying cause is treated.

Questions for Your Doctor

  • • Does my ECG show a 'Type 1' coved pattern or a 'Type 2' saddleback pattern?
  • • Was my Type 1 pattern 'spontaneous,' or did it only appear during a fever or drug test?
  • • What was my total Shanghai Score, and how many points did I get for my family history versus my ECG?
  • • If we are doing a provocation test, which medication (ajmaline or flecainide) will be used, and what are the risks?
  • • Could my ECG pattern be a 'phenocopy' caused by a recent illness, electrolyte imbalance, or medication?

Questions for You

  • • Have I recently had a high fever, a stomach virus, or changed any of my regular medications?
  • • Do I have a copy of my ECG from when I was feeling well to compare with the one that showed the Brugada pattern?
  • • Has anyone in my family ever been told they have an 'unusual' or 'borderline' ECG?

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References

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    A 32-Year-Old Man Diagnosed with Type II Brugada Syndrome on Preoperative Electrocardiogram 1 Week Before Elective Tympanoplasty.

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    Low-dose oral flecainide provocation test for Brugada syndrome: a case series.

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    PMID: 41055814
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    Ajmaline-induced Brugada Phenocopy, Right Bundle Branch Block, or Both?

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    PMID: 34595052
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    Induced Brugada syndrome: Possible sources of arrhythmogenesis.

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    PMID: 29233646
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    Shanghai Score System for Diagnosis of Brugada Syndrome: Validation of the Score System and System and Reclassification of the Patients.

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    Unmasking a Silent Killer and Understanding Sudden Cardiac Death in Brugada Syndrome: A Traditional Review.

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    Brugada Phenocopy Induced by a Lethal Methanol Intoxication.

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    European journal of case reports in internal medicine 2020; (7(2)):001374 doi:10.12890/2020_001374.

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    Brugada Phenocopy Induced by Hypovolemic Hyponatremia.

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  15. 15

    Autolytic attempt mimicking Brugada type 1 electrocardiogram pattern due to flecainide toxicity. A case report.

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    Type 1 Brugada pattern electrocardiogram induced by hypokalemia.

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    COVID-19 Vaccination-Induced Ventricular Fibrillation in an Afebrile Patient With Brugada Syndrome.

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This page explains Brugada syndrome diagnostic tests and ECG patterns for educational purposes. Always consult a cardiologist or electrophysiologist for a proper evaluation and interpretation of your specific ECG results.

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