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Brugada Syndrome.
Characteristics of Six Cases

Castro, Jesús; Dorticós, Francisco; Zayas, Roberto;
Dorantes, Margarita; Bueno, Joaquín;
Quiñones, Miguel; Fayad, Yanela

Cardiology Institute and Cardiovascular Surgery, Havana, Cuba

SUMMARY
Introduction: The Brugada syndrome is characterized by a pseudo right bundle branch block with ST segment elevation in V1-V3 leads and proneness for episodes of sudden cardiac death or syncope caused by life-threatening cardiac arrhythmias.
Methods: Six male patients, four with aborted sudden death by ventricular fibrillation, one with syncope and other with pre syncopes, were studied in the last 5 years.
Results: The electrical sign was seen constant in three patients and intermittent in the others, it was present in aVr lead in two of them too. One patient had a positive ajmaline test, with alternating morphology in V1-V2, he refused to implant an automatic defibrillator and was taken amiodarone and propranolol for 5 years without any arrhythmias, a device was implanted two months ago and he is OK, without drugs. Automatic defibrillators were implanted in the others five; one of them had 12 shocks, 9 in 72 hours for an "electrical storm" at 18 months, it was aborted with intravenous amiodarone and is on oral amiodarona for 13 uneventful months; four others did not receive shocks in the following (between 2 and 10 months), without pharmacological treatment.
Discussion: The intermittent electrical sign in aVr, and alternating morphology in V1-V2 with ajmaline test are interests elements in these cases. Treatment with amiodarona y and propranolol were "effective" in two patients; the following in the others was like reported by others authors.
Conclusions: In a male patient, with pre syncope, syncope or sudden death, in absence of structural heart disease, diagnosis of the Brugada syndrome should be thought. The treatment of choice is the automatic defibrillator.

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INTRODUCTION
   Sudden cardiac death is defined like unexpected death from a cardiac cause within 1 hour or less from the onset of symptoms. 90% are patients with structural heart disease, and 5-10% occur in patients with "normal heart". In 1992, Ramon and Jose Brugada described 8 patients with history of aborted sudden death, normal heart, and a distinct electrocardiographic (ECG) pattern, consisting of right bundle-branch block with ST segment elevation in right precordial leads (V1-V3). Abnormal ECG pattern can be reproduced with intravenous administration of ajmaline, procainamide or flecainide, in patients with transient normalized one. Is frequent in Asia, 50% of sudden death in patients with normal heart and less than 50 years old in Japan. The syndrome is often familial, genetically determined, a due to a mutations in the cardiac sodium channel. Heterogeneity of repolarization across the wall of outflow tract in the right ventricle contribute to the ECG pattern and the genesis of arrhythmias.

OBJECTIVES
   Our objectives are to expound clinical data, electrocardiographics patterns, therapy and follow up of our patients.

METHODS
   Six male patients were studied, in middle-aged (33-47 years old), in the last five and a half years. They were treated for ventricular fibrillation, syncope or presyncope. All patients were investigated: clinic history, laboratory analysis, echocardiogram, X ray, and in some of them ergometric test and coronariography (all normals).

    Electrocardiograms were analyzed by all authors, ST segment morphology was evaluated for V1 lead. Ajmaline or Procainamide test was made in order to unmask the electrical sign, it was classified positive if ST segment elevation was >1 mv and very positive if it was >2 mv. Programmed stimulation was made with 3 paced cycles length (600, 500 and 400 msec) and 3 extra stimulus to right ventricular apex, and outflow tract in some patients. Automatics defibrillators were implanted by left cephalic vein dissection or subclavia vein puncture. Fixteen Joules was programmed like first therapy shock and the others were highest. Follow up was done in ambulatory consult with medical examination, electrocardiogram, and to check up a device.

RESULTS
   Clinical data, some complementary, therapy and follow up can be seen in Tables 1, 2, 3.

   All patients were in middle-aged. Four of them suffered aborted sudden death by ventricular fibrillation, other had a syncope in Emergency (electrocardiogram was normal) and the other one had been seen by apparent hypoglycemias.

   Patient #1 had a positive ajmaline test, with alternating morphology in V1-V2 (Figure 1). An electric pattern was detected in V1 and aVr leads in patient #2 and #3 (Figure 2).

Figure 1: Patient # 1. Ajmaline test. Alternating morphology in V1-V2.

Figure 2: Patients # 2 to # 6. Electrocardiographic pattern in aVr and V1 leads in patient # 2 and # 3.

   The first patient refused implant an automatic defibrillator and was taken amiodarone (300 mg 5 days in a week) and propranolol (30 mg in a day) for 5 years, after that he accepted a device, and continued without shocks for 7 months (not drugs). Defibrillators were implanted in the others five; one of them had 11 shocks, 8 in 72 hours for an "electrical storm" at 18 months, it was aborted with intravenous amiodarone and he has been taken oral amiodarone for 19 uneventful months; four others did not receive shocks in the following (between 7 and 14 months), without pharmacological treatment.

DISCUSSION
   The Brugada syndrome is described in middle-aged, most of them in male patients, our cases are in that group.

   In many cases, malignant tachyarrhythmias occur at rest or at nighttime, especially in Southern Asia; a sudden rise in vagal activity has been reported to occur just before VF episodes in some patients where abnormally high sympathetic tone has been documented, in other mental stress and alcohol consumption are thought to be provocative factors. The activity at the moment of the arrhythmic event in our patients were watching TV, during conversation, while sleeping, and after exercises.

   Three ST segment morphologies have been described in leads V1, V2, and V3, triangular, dome and saddle-shaped. Intermittent triangular ST segment elevation was observed in aVr lead in two patients; in our opinion, it could be explained by vectorial analysis but we don't know why were intermittent when in V1 lead were constant. This phenomenon have not been reported yet

   Patient #1 had a positive ajmaline test with alternating morphology in V1-V2, a loss of dome in epicardial cells and an abbreviation of the action potentials due to pathological ionics currents, could be a cyclic phenomenon?.

   Polimorphic ventricular tachycardia or ventricular fibrillation is induced with 1-3 extra stimulus in majority of cases, but only in two we induced life threatening arrhythmias.

   The incidence of arrhythmic events during follow-up have been reported in 30%, we have one recurrence, at 10 months (patient #2), 8 months later he suffered 9 shocks in 72 hours, it was aborted by intravenous amiodarone and he has been taken oral amiodarone for 17 uneventful months in spite of amiodarone is not prescribed in these cases.

   Mortality rate is very high in patients treated with pharmacological agents such amiodarone and b-blockers, but we have a patient (#1) that was taken those drugs for 5 years, without arrhythmic events, perhaps he is not in recurrence's group in a primary follow-up, but he is in high risk of life threatening arrhythmias. The following in the others patients is too short to obtain conclusions.

CONCLUSIONS
   Many thinks of this syndrome are still unknown, but we know is very malignant. In middle-aged patients with syncope or sudden death in absence of structural heart disease, electrocardiograms most be analyzed with or without pharmacological test and the diagnosis of Brugada syndrome should be thought.

   The gold standard treatment, in symptomatic patients, is an implantable automatic defibrillator.

 

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2nd Virtual Congress of Cardiology

Dr. Florencio Garófalo
Steering Committee
President
Dr. Raúl Bretal
Scientific Committee
President
Dr. Armando Pacher
Technical Committee - CETIFAC
President
fgaro@fac.org.ar
fgaro@satlink.com
rbretal@fac.org.ar
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