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Brugada syndrome: syncope in the younger patient and the risk of sudden cardiac death
  1. A T D Mills,
  2. S Dasan,
  3. A Wan
  1. Accident and Emergency Department, Royal Surrey County Hospital, Guildford, Surrey, UK
  1. Correspondence to:
 S Dasan
 Accident and Emergency Department, Royal Surrey County Hospital, Guildford, Surrey, UK; sunil.dasansash.nhs.uk

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A 40 year old man presented to the emergency department after losing consciousness while driving his car. He had felt nauseous and light headed before managing to slow down and stop. A witness who stopped to help found him slumped unconscious over the steering wheel, and he regained consciousness a few seconds later. On arrival in hospital he was fully alert although he felt light headed and had mild chest discomfort.

He had been investigated previously for episodes of dyspnoea. Lung function tests, exercise tolerance tests, and 24 hour Holter monitoring had been unremarkable though ST segment elevation had been noted on his electrocardiogram (ECG). In the emergency department, physical examination was unremarkable though his resting ECG again showed ST segment elevation in the anterior precordial leads (fig 1). These changes were identical to those seen in the ECGs performed three years previously which had been faxed to the emergency department.

Figure 1

 Resting ECG showing right precordial ST segment elevation in leads V1–V3.

A provisional diagnosis of vasovagal syncope or syncope secondary to an arrhythmia was made and he was admitted for further investigation. ECGs performed over the following 24 hours showed no change in the anterior precordial ST segment elevation. Creatinine kinase and troponin I estimations were all within the normal range.

A cardiology opinion was sought and a possible diagnosis of Brugada syndrome was made. A provocation test was performed using 150 mg of flecainide intravenously over 10 minutes which produced significant ST elevation in leads V1–V3 (fig 2). Transthoracic echocardiography showed no structural heart disease and he was transferred for further electrophysiological studies and insertion of an implantable cardiac defibrillator device.

Figure 2

 ECG during flecainide provocation test showing marked increase in ST segment elevation in leads V1–V3.

DISCUSSION

A case of Brugada syndrome has been reported previously in this journal. The patient collapsed in cardiorespiratory arrest with a rhythm which responded to defibrillation at the scene and again on transfer to hospital.1 The present case highlights the fact that patients with Brugada syndrome can also present with syncope with no observed episode of ventricular fibrillation.

Brugada syndrome is rare, affecting only 5/10 000 of the general population, but it is the commonest cause of sudden cardiac death without structural heart disease in patients. aged younger than 50 years.2 It is characterised by a distinctive ECG pattern of ST segment elevation in the right precordial leads (V1–V3) unrelated to ischaemia, electrolyte disturbances, or obvious structural heart disease. It often presents with sudden death, usually due to sustained ventricular fibrillation, but can also present with syncope.3,4 In a review of 104 symptomatic patients with the characteristic ECG findings of Brugada syndrome, 76 (73%) presented in ventricular fibrillation and the remaining 28 (27%) presented with syncope.3 In another series of 30 symptomatic patients with a clinical and ECG diagnosis of Brugada syndrome, 13 (44%) presented with syncope and, of the remaining 17 (56%) who had survived cardiac arrest, 14 patients (82%) had a preceding history of syncope.4 Detection of Brugada syndrome in patients who present with syncope is therefore essential if further episodes of syncope or sudden cardiac death are to be avoided.

Brugada syndrome is inherited as an autosomal dominant condition with variable penetrance and is caused by three different mutations on the cardiac sodium channel gene SCN5A which results in sodium channel dysfunction.5 The diagnosis of Brugada syndrome should be considered in any person who has experienced syncope, nocturnal agonal respiration, documented ventricular fibrillation, self-terminating polymorphic ventricular tachycardia, or where there is a family history of sudden cardiac death.6 Diagnostic difficulties may arise in patients who present with syncope as these events can sometimes mimic seizure disorders with witness reports of tonic–clonic movement of extremities and urinary incontinence.7 Problems may also arise with the misinterpretation of the ECG changes thus leading to the administration of thrombolytic therapy in those with concomitant chest pain.8 Despite these diagnostic pitfalls the emergency physician evaluating the post-syncopal patient should consider the diagnosis of Brugada syndrome.

The diagnosis of Brugada syndrome is made on both clinical and ECG criteria; however, the administration of Class 1 antiarrhythmics such as amjaline, flecainide, or procainamide as sodium channel blockers may convert the subtle saddleback ST-T elevation (types 2 and 3 in fig 3) to the more typical coved-type elevation (type 1 in fig 3), which may help to confirm the diagnosis.6

Figure 3

 ST segment abnormalities in leads V1–V3 in Brugada syndrome (reproduced with permission from Wilde AMM, Antzelevitch C, Borggrefe M, et al. Proposed diagnostic criteria for the Brugada syndrome. Eur Heart J23:1649, 2002).

Untreated Brugada’s syndrome is associated with a 10% mortality per year with up to 40% of patients experiencing arrhythmias in the future.3,9 Treatment with pharmacological agents is usually unsuccessful and implantable cardiac defibrillators are the only effective measure in controlling the arrhythmias.10

Patients commonly present to emergency departments after syncopal events. The role of the emergency physician is to evaluate these patients, treat any obvious cause and establish their risk of subsequent morbidity and mortality.11 Patients with structural or electrical heart disease are at particular risk of recurrent syncope or sudden cardiac death. Patients with Brugada syndrome are generally younger and otherwise healthy. It is particularly important to recognise the characteristic ECG features so as to initiate appropriate further investigation and to confirm the diagnosis. Through increasing awareness of this treatable condition and its earlier detection, life-threatening arrhythmias and sudden cardiac death can be prevented.

CONTRIBUTORS

A Mills searched the literature and wrote the manuscript. S Dasan conducted a further literature search and edited the manuscript. A Wan initiated the writing of the case report and edited the manuscript.

REFERENCES

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Footnotes

  • Competing interests: none declared

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