What are Brugada leads (electrocardiogram electrodes)?

Brugada Leads: Specialized ECG Electrode Placement for Detecting Brugada Syndrome

Brugada leads refer to the specialized placement of ECG electrodes V1 and V2 in the 2nd or 3rd intercostal spaces (higher than standard placement) to improve detection of the characteristic Brugada pattern on electrocardiogram.

Definition and Placement

Brugada leads involve a modified electrode positioning technique:

• Standard ECG lead placement positions V1 and V2 in the 4th intercostal space
• Brugada leads involve placing these electrodes higher:
  • V1 and V2 positioned in the 2nd or 3rd intercostal spaces
  • Also called "high precordial leads" or "high right precordial leads"
• This specialized placement improves detection of the diagnostic Type 1 Brugada pattern 1, 2

Diagnostic Importance

The higher placement of these leads is critical for several reasons:

• Increases sensitivity for detecting the Brugada pattern
• May reveal a Type 1 pattern not visible on standard lead placement
• Recommended by guidelines when Brugada syndrome is suspected but not confirmed on standard ECG 1, 2
• Essential component of diagnostic workup when pattern is unclear

Anatomical Correlation

The effectiveness of high lead placement has a clear anatomical basis:

• The right ventricular outflow tract (RVOT) is the primary site of electrophysiological abnormality in Brugada syndrome
• CMRI studies show that the RVOT anatomically extends to include the 3rd intercostal space in all patients with Brugada syndrome 3
• The maximal RVOT area correlates with the location of maximal ST-segment elevation in 97% of patients 3
• This explains why higher lead placement improves diagnostic yield

Brugada ECG Patterns

When using Brugada leads, clinicians should look for:

• Type 1 (diagnostic) pattern: Coved ST-segment elevation ≥2mm followed by negative T-wave in leads V1-V3 1, 2
• Type 2 and 3 patterns (non-diagnostic): "Saddle-back" morphology with high takeoff ST-segment elevation
• The "Corrado index": Measures ST elevation at J-point (STJ) and 80ms after (ST80)
  • Type 1 Brugada pattern: STJ/ST80 ratio >1 (downsloping ST segment)
  • Early repolarization in athletes: STJ/ST80 ratio <1 (upsloping ST segment) 1

Clinical Application

When to use Brugada leads:

• When Brugada syndrome is suspected but standard ECG is non-diagnostic
• During sodium channel blocker challenge tests (with flecainide, ajmaline, or procainamide)
• For risk stratification in patients with family history of Brugada syndrome
• During fever, as elevated temperature can unmask or accentuate the Brugada pattern 1, 2

Pitfalls and Considerations

Important caveats when interpreting Brugada leads:

• ECG changes in Brugada syndrome can be dynamic and intermittent
• Right bundle branch block can complicate diagnosis
• Lead placement must be precise and consistent for accurate interpretation
• Consider potential factors that may produce Brugada-like patterns:
  • Hyperkalaemia
  • Fever
  • Sodium channel blocking medications
  • Cocaine use
  • Excessive alcohol intake 1, 2

Using Brugada leads correctly is essential for accurate diagnosis and risk stratification in patients with suspected Brugada syndrome, potentially preventing sudden cardiac death through appropriate intervention.