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The EP show: Brugada Syndrome. Eric Prystowsky, MD Director Clinical Electrophysiology Laboratory St Vincent Hospital Indianapolis, IN Josep Brugada, MD Director Arrhythmia Unit, Cardiovascular Institute Hospital Clinic, University of Barcelona Barcelona, Spain.
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The EP show: Brugada Syndrome • Eric Prystowsky, MD • Director • Clinical Electrophysiology Laboratory • St Vincent Hospital • Indianapolis, IN • Josep Brugada, MD • Director • Arrhythmia Unit, Cardiovascular Institute • Hospital Clinic, University of Barcelona • Barcelona, Spain
Brugada syndrome Description of the syndrome • A clinical and electrocardiographic syndrome • - no demonstrable structural heart disease • - suffering from cardiac arrhythmias • - a very specific ECG • apparent RBBB • ST elevation in leads V1-V3
Brugada syndrome Ionic basis of disease • The disease is associated with a mutation in sodium channel (SCN5A). • The early theory was that the syndrome reflected an increase in the Ito channel (governing the potassium current in phase 1 of the ECG). • In fact, the Ito current is only increased relative to the sodium current, because the sodium channel closes prematurely. • J Brugada
Brugada syndrome Diagnosing the syndrome • ECG definition has become more and more strict. • ST elevation of a coved type of at least 2 mm or ST elevation of saddleback type if it becomes coved type under stress with anti-arrhythmics. • Elevation is always present in V2, and either V1 or V3 (usually both). • J Brugada
Brugada syndrome Drugs for diagnosis • Flecainide used now that ajmaline is no longer available. • Given in an IV in Europe, but maybe 200mg orally but patient must be monitored for 8 hours because of the long half-life. • Procainamide is effective in unmasking the syndrome, but the ECGs are much less spectacular. May have less specificity and sensitivity than ajmaline. • J Brugada
Brugada syndrome Sensitivity and specificity • In all patients where we had genetic confirmation of the disease, we did not have a single false negative or false positive with ajmaline. • The ajmaline test was consistently reproducible in over 100 patients. • Patients’ hearts are different and the positioning of the leads can play an important role in diagnosis since the syndrome is localized in a specific region of the heart. • J Brugada
Brugada syndrome EP testing • Every single patient that has a classic Brugada ECG gets an EP test. • Asymptomatic patients who have a normal basal ECG have 0% events in follow-up so far. • So we don’t do EP tests in these patients. • Wait and watch because there is no evidence they are at risk. • J Brugada
Brugada syndrome Asymptomatics • If the base ECG is abnormal, then we follow with EP testing. • In these patients, 2/3 are non-inducible. • If non-inducible, we do nothing, because the event rate is extremely low. • Events in asymptomatic patients with abnormal basal ECG occurred in patients who were inducible by EP testing. • J Brugada
Brugada syndrome Clinical decision making • Patient with a father who died of sudden death – no ECG available. • The patient has abnormal ECG, which becomes classic Brugada after stressing with flecainide. • This patient should get EP study due to family history. • If the study is positive, give them a defibrillator. If negative, do nothing. • J Brugada
Brugada syndrome Clinical decision making • Only 60% of sudden deaths in families with known Brugada syndrome can be attributed to the syndrome. • ECGs can normalize over time. A completely normal ECG in one moment doesn’t mean it will always be normal. • If the ECG ever becomes abnormal, you then follow up with drug tests and then EP testing. • J Brugada
Brugada syndrome Clinical decision making • A 28 year old uncle who died suddenly, no ECG available. My father died suddenly at 46. No autopsy. • The kid has a classic Brugada ECG but is non-inducible to EP testing. • I would suggest a defibrillator due to the strong family history, but there is no evidence that the risk is extremely high. • But with the strong family history and the baseline Brugada ECG, I would be nervous. • J Brugada
Brugada syndrome Review • Definition of Brugada ECG: • RBBB in V1-V3 (V2 most important) • Coved ST-segment elevation of > 2mm • If not present at baseline, ECG can be induced by flecainide or procainamide. • ICD is treatment of choice for patients with documented cases of serious arrhythmias • In general if the EP study shows no inducible VT, watch and wait.