Heart rate complexity analysis in Brugada syndrome during physical stress testing

Area of Science:

• Cardiology
• Autonomic Neuroscience
• Medical Technology

Background:

• Brugada syndrome (BS) is associated with life-threatening ventricular arrhythmias, often occurring at rest.
• Autonomic nervous system (ANS) dysfunction is implicated in BS arrhythmogenesis.
• Assessing ANS response through heart rate variability (HRV) may offer insights into BS pathophysiology.

Purpose of the Study:

• To evaluate ANS response using nonlinear HRV measures in BS patients during a physical stress test.
• To determine if HRV can differentiate between symptomatic and asymptomatic BS patients.
• To explore the potential of HRV indicators for risk stratification in asymptomatic BS.

Main Methods:

• Sixty-nine BS patients underwent a standardized physical stress test.
• Nonlinear HRV analysis, specifically power-law scaling (β slope), assessed heart rate complexity (HRC).
• HRC was measured during rest, exercise, recovery, and post-recovery rest phases.

Main Results:

• Symptomatic BS patients exhibited significantly reduced HRC compared to asymptomatic patients post-exertion.
• A significant decrease in HRC was observed in symptomatic patients during the entire recovery period and passive recovery phase.
• Reduced HRC was also noted during rest post-recovery in symptomatic individuals.

Conclusions:

• Lower ANS complexity, indicated by reduced HRC, is associated with symptomatic Brugada syndrome, particularly during parasympathetic predominance.
• Nonlinear HRV measures show promise as tools for risk stratification in asymptomatic BS patients.
• These findings highlight the role of ANS dysfunction in BS and suggest HRV as a potential biomarker.