This randomized, sham-controlled, and blinded clinical trial aims to evaluate the effects of radiofrequency catheter ablation on the phenotypic expression of patients with Brugada syndrome. The main questions it seeks to address are: * What are the immediate effects of radiofrequency catheter ablation on cardiac electrophysiology? * Is substrate-directed radiofrequency catheter ablation safe for patients with Brugada syndrome? * Is substrate-directed epicardial radiofrequency catheter ablation effective in normalizing the electrocardiographic pattern and preventing life-threatening arrhythmic events? Researchers will compare the ablation group with the control group to determine if there are differences in clinical and invasive markers of the disease after one year of follow-up.
Brugada syndrome (BS) is a cardiac disorder characterized by a specific electrocardiographic pattern and an increased risk of cardiac arrhythmias and sudden death. Most arrhythmic events occur during periods of rest, fever, or situations of heightened vagal activity. Over the past decade, catheter ablation has emerged as a valuable and potentially curative treatment for patients with BS. However, there is limited knowledge of its mechanisms or of its long-term effects on clinical and invasive markers. This single-center, randomized, sham-controlled, and masked pilot study aims to investigate the impact of catheter ablation in 20 patients with Brugada syndrome. Participants will be randomly assigned to either the ablation or control group in a 1:1 allocation ratio and will be clinically monitored for at least 12 months following the intervention.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
20
Radiofrequency application via catheter to burn the electroanatomic substrate implicated in Brugada syndrome
Venous and epicardial punctions, catheter insertions, programmed electrical stimulation and electroanatomical mapping
Instituto do Coração - InCor - HC/FMUSP
São Paulo, São Paulo, Brazil
Activation recovery interval (ARI)
The activation recovery interval, which serves as a surrogate marker for the duration of the action potential, will be measured on both the epicardial and endocardial surfaces of the right ventricular outflow tract. This measurement will be taken from the onset of the minimum of the derivative of ventricular activation (dVdT) to the end of ventricular repolarization, following the classic methodology
Time frame: First 30 minutes after the intervention
Area of abnormal electrical potentials measured in square centimeters (cm²)
Abnormal electrical potentials were defined as low-frequency electrograms (up to 100 Hz) with prolonged duration (\>200 ms), fragmented patterns (more than three deflections), and late components extending beyond the QRS complex
Time frame: First 30 minutes after the intervention
Local activation time
Measured by unipolar catheters placed in the epicardial and endocardial ventricular surfaces
Time frame: First 30 minutes after the intervention
Maximum potential duration
Maximum length of ventricular signs on bipolar electrogram
Time frame: First 30 minutes after the intervention
Induction of sustained ventricular arrhythmias by programmed electrical stimulation
Programmed electrical stimulation will be performed at two locations: the right ventricular apex and the right ventricular outflow tract, unless the patient experiences inducible ventricular tachycardia at the first site. The stimulation will use energy that is twice the diastolic threshold. Two drive cycles will be implemented: S1 at 600 ms and S1 at 430 ms. Up to two additional stimuli (S2 and S3) will be applied, with a minimum coupling time of 200 ms. A positive result from the programmed ventricular stimulation is identified if sustained ventricular fibrillation or polymorphic ventricular tachycardia is induced.
Time frame: Immediately (first 30 minutes) after the intervention and again 12 months after
Acute post-procedure complications
Acute post-procedure complications were monitored over a three-day hospital stay, focusing on major events such as sustained ventricular arrhythmias, cardiac arrest, death, thromboembolic events, subxiphoid puncture accidents (significant bleeding (≥ 500 ml), or pericardial tamponade necessitating surgical intervention), and pericarditis. Diagnosis of pericarditis was based on characteristic pain, pericardial effusion, electrocardiographic findings (PR segment depression and diffuse ST-segment elevation), and elevated serum inflammatory markers.
Time frame: During the first 72 hours following the intervention
Spontaneous type 1 Brugada electrocardiographic pattern in standard12 lead and superior leads electrocardiogram
Upward ST segment elevation ST-segment elevation ≥2 mm followed by a negative T wave (type 1 Brugada electrocardiographic pattern) in one or more right precordial leads V1 and/or V2 positioned in the second, third, or fourth intercostal spaces.
Time frame: Up to one year after the procedure
Spontaneous type 1 Brugada electrocardiographic pattern during treadmill test
Upward ST segment elevation ST-segment elevation ≥2 mm followed by a negative T wave (type 1 Brugada electrocardiographic pattern) in one or more right precordial leads V1 and/or V2 positioned in the second, third, or fourth intercostal spaces, during treadmill test.
Time frame: Up to one year after the procedure
Spontaneous type 1 Brugada electrocardiographic pattern in 12 lead 24 hour Holter monitoring
Upward ST segment elevation ST-segment elevation ≥2 mm followed by a negative T wave (type 1 Brugada electrocardiographic pattern) in one or more right precordial leads V1 and/or V2 positioned in the second, third, or fourth intercostal spaces during 12 lead 24h Holter ECG Monitoring
Time frame: Up to one year after the procedure
Brugada type 1 electrocardiographic pattern induced by sodium channel blocker challenge
Upward ST-segment elevation ≥2 mm followed by a negative T wave (type 1 Brugada electrocardiographic pattern) in one or more right precordial leads V1 and/or V2 positioned in the second, third, or fourth intercostal spaces after an ajmaline challenge after an ajmaline challenge
Time frame: During the electrophysiological study, conducted 12 months after the intervention
Occurrence of life threatening arrhythmic events
Occurrence of at least one of the following: arrhythmic syncope, documented sustained ventricular tachycardia or ventricular fibrillation, sudden cardiac death or appropriate implantable cardiac defibrillator therapy
Time frame: At least one year after the intervention
Combined efficacy endpoint
Induced sustained ventricular arrhythmias during programmed ventricular stimulation one year after the intervention or any life-threatening events (such as arrhythmic syncope, spontaneous sustained ventricular arrhythmias, appropriate ICD therapy, or sudden arrhythmic death) throughout at least 12 months of follow-up.
Time frame: At least one year after the intervention
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