Brugada Syndrome: Sudden Cardiac Death | Literature Review

BRUGADA SYNDROME: SUDDEN CARDIAC DEATH

Review of Literature and Case Report.

• Dr. Nanda Pai
• Dr. Sanjeeta Umbarkar
• Dr. Akshay Bafna
• Dr. Jinal Vaghela

KEYWORDS:

Brugada Syndrome, sudden unexpected death syndrome (SUDS)

ABSTRACT

Brugada Syndrome or Sudden Unexpected Death Syndrome was first discovered by P. Brugada and J. Brugada in 1992¹. It is a rare genetic disorder characterised by ST segment elevation in V₁ – V₃ leads on ECG, ventricular fibrillation and ventricular arrhythmias which can cause sudden unexpected death in an otherwise normal patient. We wish to highlight the fact that with thorough pre-operative anaesthetic and cardiac evaluation these potentially life threatening patients can be effectively treated for minor oral surgical procedures using regional anaesthesia with lignocaine thereby avoiding general anaesthesia.

INTRODUCTION

“In 1992, Pedro and Josep Brugada for the first time introduced a new clinical entity with ST segment elevation in V₁ – V₃ leads and right bundle branch block (RBBB) pattern associated with a high incidence of ventricular tachycardia/ventricular fibrillation (VT/VF)¹”. This new entity was termed Brugada Syndrome (BrS) or Sudden Unexpected Death Syndrome (SUDS), occurring in structurally healthy hearts in young individuals, causing life threatening arrhythmias and sudden death. Most of the patients are between second and fourth decades of life however “the youngest patient clinically diagnosed with the syndrome is 2 days old and the oldest is 84 years old²”. There is a male predilection, “due to the presence of more prominent I­_to channels in males than in females³” and in many countries it is the 2^nd highest cause of death in younger men after vehicular accidents.

Signs and symptoms include presyncopal and syncopal attacks and cardiac arrest (many a times during sleep). Routine ECG shows ST segment elevation in leads V₁ – V₃. Fever may precede syncope or tachycardia. There are 3 types of Brugada ECG Patterns

Type 1: coved type, where ST segment elevation > 2 mm.

Type 2: saddle back type, where ST segment elevation > 2mm with positive ‘T’ wave.

Type 3: coved or saddle back type, where ST segment elevation < 1mm with inverted T wave.

Brugada Syndrome is inherited as an autosomal dominant trait. In 1998, the Syndrome was linked to mutations in SCN5A, the gene that encodes the alpha subunit for the sodium channel and since then over 300 mutations of SCN5A have been identified⁴. Mutations of gene SCN5A cause loss of expression of sodium channel protein which decreases the sodium current resulting in slow conduction in the heart. Bezzina et al presented evidence supporting the theory that an SCN5A promoter polymorphism, common in Asian modulates, variability in cardiac conduction and may contribute to the high prevalence of Brugada Syndrome in Asian population⁵.

CASE REPORT

A 27 year old male patient reported in the department of dentistry, with excruciating pain in lower right second molar and insisted on getting it extracted. Clinical examination and orthopantomogram revealed an extremely carious second molar. The patient was a recently diagnosed case of Brugada Syndrome (Type 3). He gave a history of chest pain about 7 years ago, however, a couple of months ago he had persistent chest pain for which he was admitted in the intensive care unit for about 10 days, during which time he had 3 presyncopal attacks. On cardiac evaluation, ECG revealed an elevated ST segment in V₁ – V₃ leads and partial RBBB pattern but structurally normal heart valves with normal pericardium and absence clots or vegetation. His left ventricular ejection fraction was 60%. CST (Cardiac Stress Test) was performed by Bruce protocol where patient walked for 30 minutes with 10.1 METS which showed no angina/arrhythmia. Basal ECG showed RBBB persisted throughout the test. However there were no significant ST segment changes during the test. Adequate chronotropic and ionotropic response was achieved. CST was negative for stress induced reversible ischaemia/and for arrhytmia. His family history revealed sudden death of his father at a younger age (42 years) with unknown cause. However, there was no diagnosed case of Brugada Syndrome in the family. His past surgical history revealed an appendicectomy and septoplasty. He was a chronic smoker and occasionally consumed alcohol.

Since it was a minor dental surgical procedure and given the patient’s history, the tooth extraction was planned under local anaesthesia using lignocaine hydrochloride with adrenaline (1:2, 00,000) thereby avoiding general anaesthesia and the various drugs used with it that could trigger ventricular tachycardia in a BrS patient. Given the patient’s history of chest pain and diagnosis of Brugada Syndrome, patient was thoroughly evaluated by the anaesthetist and cardiologist prior to the dental treatment. High risk fitness was obtained.

The patient was taken up in the intensive care unit. A ventilator and a defibrillator were kept standby. A 12 lead ECG was attached and was monitored continuously throughout the procedure. An I.V. line was secured. The anaesthetist and cardiologist along with the maxillofacial surgeons formed the surgical team. A right inferior alveolar nerve block was given using 3 ml lignocaine with adrenaline solution. Another 1 ml was used for intra-pulpal infiltration. After checking for subjective and objective signs the tooth was surgically extracted after sectioning the roots. The wound was closed using 3 – 0 vicryl. Patient tolerated the procedure well. Intra operatively patient was given 4 mg Dexamethasone along with injection Augmentin (Amoxicillin Clavulanate) 1.2 gm. Post operatively he was put on oral tablet Augmentin 625 mg and tablet Paracetamol twice a day. Patient was discharged the same day and was followed up in the dental department.

DISCUSSION

Brugada Syndrome is a major cause of sudden unexplained death syndrome (SUDS) and death is caused by ventricular tachycardia and fibrillation (a lethal arrhythmia) in the heart which appears with no warning. The diagnosis in Brugada Syndrome is based on the characteristic patterns on an electrocardiogram, which may be routinely precipitated by administration of certain drugs (ajmaline or flecainide). Brugada ECG pattern is very often hidden, but certain factors can unmask or trigger it like sodium channel blockers, febrile state, vagotonic agents, autonomic nervous system changes, excessive stress, tricyclic or tetracyclic antidepressants, first generation antihistamines (dimenhydrinate), a combination of glucose and insulin, hyperkalaemia, hypokalaemia, hypercalcaemia, alcohol toxicity, heavy meals at night just before sleeping, excessive vomiting, hot humid climatic conditions⁶.

According to Nademanee and Veerakul⁶, north-eastern part of Thailand where SUDS is prevalent and where temperatures can soar to 41^oC a study is underway to gauge the climatic influences on occurrence of SUDS and they feel that physicians should factor in temperature as a cause of arrhythmogenesis in BrS. Several drugs could precipitate ventricular tachycardia and fibrillation which are listed in world Brugada registry in http://www.brugadadrugs.org (Accessibility verified July 04, 2014). All Brugada patients and their treating physicians should be aware of these precipitating drugs at all times.

Many Brugada patients are asymptomatic and the classical pattern on ECG is picked up only by an experienced and trained physician. This pattern should be correlated with age of patient, family history, chest pain, fever and presyncopal/syncopal attacks. Bupivacaine has been reported to unmask Brugada like ECG patterns when administered epidurally⁷. Hence we avoided bupivacaine and used lidocaine with adrenaline (1:2, 00,000 dilution) instead for our patient which was well tolerated by him. Lignocaine (class 1b antiarrythmic agent) displays rapid dissociation kinetics and produces little to no ST segment elevation in patients with congenital BrS⁸. The ventricular tachycardia in BrS can be prevented by avoiding certain aggravating factors like medication, drugs, fever and excessive stress. Brugada patients need to be regularly followed up over a long period of time. In severe cases the only line of treatment is placement of an implantable cardioverter defibrillator (ICD).

Kloesel et al⁹ in 2011 did a literature search and compared results of previous reports with theirs regarding outcomes of patients with BrS who underwent surgeries and anaesthetic care and found 21 case reports and 4 case series. They collected data of 52 anaesthetics and 43 patients. In our literature search we found mention of only 2 patients of BrS who underwent surgeries in the maxillofacial region. 1) Plate fixation for mandibular fracture in 56 year old male. 2) Tooth extraction, incision and drainage of odontogenic infection in 55 year old male¹⁰. However both these patients were treated under general anaesthesia. We decided to avoid general anaesthesia thereby keeping the drugs to be used to the minimum.

By thorough pre-anaesthetic evaluation, proper patient counselling, intra-operative pain control using optimum amount of lignocaine, 12 lead ECG continuously monitored at all times during procedure, constant blood pressure monitoring, avoiding use of certain drugs like bupivacaine, keeping a defibrillator standby and by having a cardiologist and anaesthetist in your surgical team these patients can be successfully managed. Post-operatively ICU monitoring is must for a minimum of 4 hours. There is a dearth of articles in the Maxillofacial and Dental literature regarding the management of these patients and we feel there is a need of more awareness of this not so rare cardiac condition among the dental and maxillofacial surgeons. With proper planning these patients with potentially life threatening and unique cardiac conditions can be safely and efficiently managed by maxillofacial surgeons for dental treatment.

FUNDING

None.

COMPETING INTERESTS

None declared.

ETHICAL APPROVAL

Not Required.

ACKNOWLEDGEMENTS

The authors would like to thank Dr. Kuldeep and Dr. Arvind Singh, 1^st year Residents, Department of Cardiology, KEMH; Dr. Yogesh Naik, Assistant Professor, Department of Anaesthesia, KEMH for their support throughout the treatment and co-operation.

REFERENCES

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