The BrS Risk Score: Applying the Shanghai Score in Clinical Practice
Brugada syndrome (BrS) is an inherited arrhythmia syndrome associated with ventricular fibrillation, polymorphic ventricular tachycardia, and sudden cardiac death, often in structurally normal hearts. Its diagnosis can be difficult because the characteristic type 1 electrocardiographic pattern may be intermittent, fever-dependent, or unmasked only after sodium-channel blocker administration.
The Shanghai score provides a structured way to combine electrocardiographic findings, clinical events, family history, and genetic information. Used carefully, it can reduce reliance on a single tracing or an isolated symptom. It is especially useful when the clinical picture is suggestive but does not fit a simple diagnostic pathway.
The score should not be treated as an automatic indication for an implantable cardioverter-defibrillator (ICD), nor as a stand-alone prediction model for future ventricular arrhythmia. Its value lies in organizing evidence, identifying patients who require specialist assessment, and supporting decisions within the broader context of electrophysiology practice.
Why the Shanghai score matters
The Brugada ECG pattern can appear in healthy individuals, during fever, after exposure to certain medications, or as a transient finding with limited clinical context. A type 1 pattern is central to the diagnosis, but its significance depends on how it was obtained and whether the patient has experienced an arrhythmic event.
Before the Shanghai system, clinicians often had to reconcile several partially overlapping consensus definitions. This created uncertainty in patients with syncope, a family history of sudden death, or a suspicious but non-diagnostic ECG. The scoring system offers a common language for documenting the strength of evidence.
It also encourages clinicians to separate diagnostic evidence from prognostic evidence. A patient may meet criteria for BrS without having a high short-term risk of ventricular fibrillation, while another patient with a lower total score may have a compelling history of cardiac arrest. Clinical judgment remains essential.
What the score measures
The Shanghai framework draws evidence from four broad domains: ECG findings, clinical history, family history, and genetic testing. The ECG domain generally contributes the greatest weight, particularly when a type 1 pattern is recorded spontaneously in the high right precordial leads.
A type 1 pattern induced by fever is highly relevant, while a pattern elicited by a sodium-channel blocker is also important but carries a different evidentiary weight. Type 2 or type 3 patterns may prompt further assessment, yet they do not establish the diagnosis by themselves. Lead placement in the second, third, or fourth intercostal space can improve detection when suspicion remains high.
Clinical history includes documented ventricular fibrillation or polymorphic ventricular tachycardia, unexplained cardiac arrest, and syncope judged likely to be arrhythmic. Nocturnal agonal respiration is another recognized feature. These findings must be distinguished from vasovagal syncope, orthostatic symptoms, panic episodes, seizures, and sleep-disordered breathing.
Family history and genetics add supporting evidence. Sudden cardiac death at a young age, a family member with a confirmed BrS diagnosis, and a pathogenic variant in a relevant gene such as SCN5A may increase the score. A negative genetic test does not exclude BrS, because the known genetic causes explain only a proportion of clinically diagnosed cases.
Interpreting ECG and clinical evidence
A type 1 Brugada pattern consists of a coved ST-segment elevation of at least 2 mm in one or more right precordial leads, followed by a negative T wave. The tracing should be reviewed for technical quality, lead position, confounding drugs, electrolyte abnormalities, ischemia, and other phenocopies.
Fever is a particularly important trigger. Patients with a suspected or established Brugada phenotype should receive prompt evaluation for significant fever, with appropriate antipyretic treatment and monitoring when the ECG changes are marked or symptoms occur. A fever-associated pattern should be interpreted alongside the patient’s history rather than considered harmless or automatically equivalent to a spontaneous pattern.
Drug challenge testing requires specialist supervision, continuous ECG monitoring, resuscitation capability, and a clear clinical rationale. Ajmaline, flecainide, or another validated sodium-channel blocker may be used according to local protocols. The test can expose a latent phenotype, but the result should be interpreted in the context of pretest probability and alternative diagnoses.
The history of syncope deserves particular attention. Sudden loss of consciousness without prodrome, occurrence during rest or sleep, associated palpitations, injury, or a documented arrhythmia increases concern. A prolonged prodrome, upright posture, identifiable trigger, and rapid recovery may instead support reflex or orthostatic syncope. The scoring system cannot replace a careful witness account, physical examination, ambulatory monitoring, and targeted testing.
Moving from score to bedside decisions
The Shanghai score is commonly interpreted using broad diagnostic categories: a total of 3.5 points or more supports a probable or definitive BrS diagnosis, a score around 2 to less than 3.5 suggests a possible diagnosis, and a lower score makes the diagnosis less likely. Exact interpretation should follow the current consensus document and institutional practice, particularly in borderline cases.
The following summary shows how the main evidence domains contribute to clinical reasoning. Point values can differ according to the specific finding, and clinicians should consult the current scoring criteria rather than estimate points from a simplified chart.
| Evidence domain | Examples of findings | Clinical role | Practical caution |
|---|---|---|---|
| ECG | Spontaneous type 1 pattern, fever-induced type 1 pattern, drug-induced type 1 pattern | Provides the core diagnostic evidence | Confirm lead placement and exclude phenocopies |
| Clinical history | Cardiac arrest, documented ventricular arrhythmia, likely arrhythmic syncope, nocturnal agonal respiration | May substantially strengthen diagnostic confidence and influence risk assessment | Do not label unexplained fainting as arrhythmic without supportive features |
| Family history | Sudden cardiac death at a young age or confirmed BrS in a relative | Adds context and may support family evaluation | Family reports should be verified when possible |
| Genetic findings | Pathogenic variant associated with BrS, particularly in SCN5A | Supports a diagnosis in the appropriate phenotype | A negative result does not rule out disease |
| Overall interpretation | Combined score across domains | Helps classify diagnostic likelihood | It is not an isolated ICD decision rule or a complete SCD prediction model |
A patient with a spontaneous type 1 pattern and a resuscitated cardiac arrest is managed differently from an asymptomatic person with a drug-induced pattern and no family history. Both may accumulate diagnostic points, but the clinical urgency, counseling, and device discussion are not equivalent.
For this reason, the score should be recorded with the circumstances of each finding. “Type 1 ECG” is less informative than “type 1 ECG recorded spontaneously during evaluation for nocturnal syncope” or “type 1 pattern induced during monitored ajmaline challenge.”
Avoiding common misclassification
One frequent error is assigning excessive importance to type 2 or type 3 patterns. These patterns can resemble BrS but are not diagnostic without conversion to type 1 under appropriate conditions. Early repolarization, right ventricular conduction delay, pectus excavatum, acute myocardial disease, electrolyte disturbance, and certain medications can produce misleading appearances.
Another error is using the score as a substitute for a differential diagnosis. Brugada phenocopies may occur with metabolic abnormalities, myocardial ischemia, mechanical compression, or systemic illness. The ECG should be reassessed after the provoking condition resolves, and the patient should be evaluated for structural heart disease when clinically indicated.
Genetic testing also needs careful framing. A pathogenic SCN5A variant can support the diagnosis, but variants of uncertain significance should not be counted as diagnostic evidence. Genetic counseling helps explain incomplete penetrance, variable expression, the limits of testing, and the implications for relatives.
The score should be updated when new information becomes available. A previously asymptomatic patient may later experience syncope, documented ventricular arrhythmia, or a new spontaneous type 1 ECG. Conversely, a suspected diagnosis may be weakened when an alternative cause for the ECG or symptoms is established.
Integrating monitoring, family care, and modern tools
Assessment does not end when the score is calculated. Depending on the presentation, clinicians may use ambulatory ECG monitoring, implantable loop recording, exercise testing, echocardiography, cardiac magnetic resonance imaging, or electrophysiology consultation. These tools help investigate symptoms and exclude other causes rather than simply add points to the score.
Family evaluation should be individualized. First-degree relatives of a patient with confirmed BrS may require ECG assessment, review of fever management, medication counseling, and genetic testing when a clinically relevant familial variant is identified. Children and adolescents need age-appropriate evaluation, particularly when there is a strong family history of sudden death.
Digital analysis may support screening and workflow, but it cannot replace expert interpretation. Resources discussing AI-assisted ECG interpretation illustrate how automated methods may help identify patterns across large datasets. In BrS, however, algorithms must be validated for lead placement, intermittent phenotypes, fever-related changes, and clinically important false positives.
Clinicians should also keep current with evolving evidence on drug avoidance, fever treatment, catheter ablation, ICD therapy, and inherited arrhythmia care. Reviews and consensus updates collected in arrhythmia special issues can provide useful context when local protocols are being developed or revised.
A practical workflow for clinical teams
A consistent workflow makes the Shanghai score more reliable and improves communication between emergency physicians, cardiologists, genetic counselors, and electrophysiologists. Documentation should capture the ECG conditions, symptom characteristics, family history details, genetic report language, and any suspected alternative diagnosis.
Practical safeguards include:
- Repeat and review ECGs with correct right precordial lead placement, including higher intercostal positions when appropriate.
- Treat fever promptly and reassess the ECG, while arranging monitoring for patients with symptoms or marked electrical changes.
- Classify syncope from the full history and witness account rather than assigning an arrhythmic label based on the absence of an obvious cause.
- Use sodium-channel blocker challenge only in a suitably monitored specialist setting and according to an approved protocol.
- Separate diagnostic scoring from decisions about ICD implantation, ablation, sports participation, medication use, and family screening.
The final clinical note should state both the calculated score and its limitations. It should explain whether the patient has a confirmed, probable, possible, or unlikely BrS phenotype; identify the evidence supporting that assessment; and describe the plan for follow-up. This approach prevents a numerical result from obscuring the patient’s actual arrhythmic risk.
Apply the Shanghai framework as a structured starting point, then place it within a complete electrophysiology assessment. Review the latest consensus guidance, document the evidence behind every point, and refer uncertain or high-risk cases to an experienced inherited arrhythmia service.