Can you explain the differences between Brugada syndrome and Wellens syndrome, including their characteristic electrocardiogram patterns, clinical significance, and recommended management, and provide illustrative diagrams?

Brugada vs Wellens Syndrome: Key Differences

Brugada syndrome and Wellens syndrome are fundamentally different conditions—Brugada is an inherited channelopathy causing sudden cardiac death from ventricular fibrillation, while Wellens syndrome is an acute coronary syndrome pattern indicating critical LAD stenosis requiring immediate revascularization.

Brugada Syndrome

ECG Characteristics

Type 1 (Diagnostic Pattern): 1

• "Coved" ST-segment elevation ≥2 mm in V1-V2/V3
• Downsloping ST segment with ST/ST80 ratio >1
• Followed by negative T wave
• May require high lead placement (2nd-3rd intercostal space) for detection 2

Type 2 Pattern (Non-diagnostic):

• "Saddleback" morphology with high takeoff (≥2 mm)
• ST elevation remains ≥1 mm above baseline
• Followed by biphasic or positive T wave 1

Key Features:

• Right precordial leads (V1-V3) only
• No reciprocal S-wave in leads I and V6 (unlike RBBB) 1
• Dynamic—can normalize completely over time
• Provoked by fever, sodium channel blockers (flecainide, ajmaline), vagal tone 1, 2

Clinical Significance

• Genetic disorder: SCN5A mutation in ~25% of cases 2
• Risk of sudden cardiac death from ventricular fibrillation 2
• Predominantly affects young males (90% male predominance) 3
• Peak presentation: 3rd-4th decade 3
• Structurally normal heart 2

Management Algorithm 2

Symptomatic patients (syncope or cardiac arrest):

• ICD implantation (Class I recommendation)
• Highest mortality risk with spontaneous Type 1 pattern + symptoms

Asymptomatic patients with spontaneous Type 1:

• Observation without treatment if truly asymptomatic
• EP study may be considered for risk stratification (controversial—low positive predictive value) 4
• Avoid triggers: fever (aggressive treatment), certain medications (www.brugadadrugs.org), alcohol, cocaine 2

Suspected Brugada without spontaneous Type 1:

• Sodium channel blocker challenge (flecainide/ajmaline) to unmask pattern 2
• Positive challenge in asymptomatic patients does not require therapy

Acute management of VF storm:

• Isoproterenol infusion
• Consider quinidine (38% adverse effect rate) 2
• Catheter ablation of RV epicardial substrate (limited experience) 2

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Wellens Syndrome

ECG Characteristics 5, 6, 7

Type A (25% of cases):

• Biphasic T waves in V2-V3 (may extend to V1-V6)
• Represents earlier/evolving phase

Type B (75% of cases):

• Deeply inverted symmetric T waves in V2-V3 (may extend to V1-V6)
• Represents later/reperfusion phase

Critical Diagnostic Criteria:

• Pain-free interval when ECG obtained (reperfusion state) 5
• Normal or minimally elevated troponin
• Preserved R waves (no Q waves)
• No significant ST elevation in precordial leads
• Dynamic pattern—can transition from A to B within 6-12 hours 6, 8

Clinical Significance

• Indicates critical proximal LAD stenosis (>70%) 5, 9
• High risk of anterior STEMI if not revascularized (75% progress to MI within weeks)
• Represents reperfusion after transient LAD occlusion 5
• Often missed because patients appear stable at presentation 5, 9

Management Algorithm 5, 9

Immediate actions:

• Urgent cardiology consultation
• Early coronary angiography (within 24 hours)
• Percutaneous coronary intervention of LAD lesion
• Admit to monitored bed
• Avoid stress testing (contraindicated—can precipitate MI)

Medical therapy pending catheterization:

• Dual antiplatelet therapy
• Anticoagulation
• Beta-blockers
• Statins
• Avoid discharge from emergency department

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Key Differentiating Features

Feature	Brugada	Wellens
Pathophysiology	Ion channelopathy (Na+ channel dysfunction)	Acute coronary syndrome (LAD stenosis)
Leads affected	V1-V2/V3 (right precordial only)	V2-V3 (anterior, may extend laterally)
Primary abnormality	ST elevation (coved or saddleback)	T wave changes (biphasic or inverted)
Structural disease	None	Critical coronary stenosis
Timing	Chronic/intermittent pattern	Acute, evolving over hours
Clinical context	Often asymptomatic or syncope	Recent chest pain, now pain-free
Troponin	Normal	Normal or minimally elevated
Risk	Sudden death from VF	Anterior MI if untreated
Treatment	ICD if symptomatic; avoid triggers	Urgent revascularization
Age/Gender	Young males (30s-40s)	Middle-aged adults, either sex

Critical Pitfalls to Avoid

For Brugada:

• Don't confuse with RBBB (look for reciprocal S waves in I and V6—absent in Brugada) 1
• Don't miss dynamic changes—repeat ECGs if suspicion high
• Don't forget high lead placement (2nd-3rd intercostal space) increases detection 2
• Recognize that Type 2/3 patterns are NOT diagnostic alone 1, 10

For Wellens:

• Don't discharge patients with this pattern—they need urgent catheterization 9
• Don't perform stress testing (can precipitate MI)
• Don't be falsely reassured by normal troponin or lack of chest pain 5
• Recognize pattern can evolve rapidly (A to B transition in 6-12 hours) 6, 8
• Don't miss extended patterns beyond V2-V3 (V1-V6 involvement still indicates LAD disease) 7

The fundamental distinction: Brugada requires recognition and risk stratification for sudden death prevention, while Wellens demands immediate action to prevent imminent myocardial infarction.