What are the signs and symptoms of Brugada Syndrome?

Signs and Symptoms of Brugada Syndrome

Brugada syndrome is characterized by distinctive ECG abnormalities and increased vulnerability to ventricular fibrillation and sudden cardiac death, occurring in the absence of structural heart disease. 1

Key Clinical Manifestations

Symptoms

• Syncope: Often the first presenting symptom, particularly in young to middle-aged adults 1
• Cardiac arrest: May occur without warning, especially during sleep or rest 1, 2
• Palpitations: May precede syncopal episodes 1
• Nocturnal agonal respiration: Breathing difficulties during sleep 2

Timing and Triggers

• Sleep-related events: Cardiac events predominantly occur during sleep or rest 1, 2
• Fever-induced episodes: Fever can acutely trigger cardiac arrest or unmask the ECG pattern 1
• Vagal stimulation: Increased vagal tone or withdrawal of sympathetic activity may precipitate arrhythmias 1

Electrocardiographic Features

Diagnostic ECG Patterns

• Type 1 Brugada pattern (diagnostic): Coved ST-segment elevation ≥2mm followed by a negative T-wave in right precordial leads (V1-V3) 1
• Type 2 Brugada pattern: "Saddleback" morphology with high takeoff ST-segment elevation, remaining ≥1mm above baseline, followed by a biphasic or positive T-wave 1
• Type 3 Brugada pattern: Either coved or saddleback morphology with J-point elevation ≥2mm but terminal portion of ST-segment <1mm 1

Additional ECG Findings

• Intermittent pattern: ECG changes may be transient and dynamic 1, 3
• S1, S2, S3 pattern: May mimic left anterior hemiblock 1
• Conduction abnormalities: Prolonged PR interval (>200ms) and QRS prolongation in V2 (≥120ms) 3
• Fragmented QRS complexes: Associated with increased arrhythmic risk 3

Demographics and Risk Factors

• Male predominance: >90% of clinically affected individuals are male 1, 2
• Age of presentation: Typically third and fourth decades of life 1
• Genetic factors: Autosomal dominant inheritance pattern, with SCN5A mutations accounting for 15-30% of cases 1, 4
• Geographic distribution: Higher prevalence in Southeast Asian populations 2

Important Clinical Considerations

Risk Stratification

• Spontaneous Type 1 ECG pattern carries higher risk than drug-induced pattern 1
• History of syncope with spontaneous Type 1 ECG indicates 6-fold higher risk of cardiac arrest 1
• Asymptomatic individuals with characteristic ECG may still be at risk, regardless of family history 1

Diagnostic Challenges

• ECG changes can be intermittent and may require provocative testing with sodium channel blockers 1, 3
• Modified lead placement (V1-V2 in 2nd or 3rd intercostal space) may improve detection 1
• Fever, electrolyte disturbances, and increased vagal tone can enhance ST-segment elevation 1

Differential Diagnosis

• Early repolarization patterns in athletes (upsloping ST-segment with STJ/ST80 ratio <1) 1
• Brugada phenocopy: similar ECG pattern due to other conditions (e.g., pneumopericardium, pericarditis) 5
• Incomplete right bundle branch block 3

Recognizing these signs and symptoms is crucial for early diagnosis and management of Brugada syndrome to prevent sudden cardiac death, particularly in young adults with no apparent structural heart disease.