Published 11 February 2009, doi:10.1136/bmj.a3087
Cite this as: BMJ 2009;338:a3087

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An unusual case of palpitations

Simon W Dubrey, consultant cardiologist, Sanjay K Kohli, specialist registrar in cardiology, Paresh A Mehta, specialist registrar in cardiology, Richard Grocott-Mason, consultant cardiologist

1 Hillingdon Hospital, Uxbridge, Middlesex UB8 3NN

Correspondence to: S K Kohli skkohli{at}doctors.org.uk

A 66 year old white man presented with a three year history of intermittent frequent (daily) palpitations and associated malaise, but no syncope. He was taking no drugs and had no family history of arrhythmia or of unexplained, sudden, or premature death. Clinically he was afebrile, in sinus rhythm at 60 beats/min, had blood pressure of 130/80 mm Hg, and had normal heart sounds. Serum electrolytes, including magnesium, and haematology and hepatic and thyroid function tests were normal. His electrocardiogram (ECG) is shown in the figure 1Go. A seven day ECG event recorder showed two episodes (of 16 and 17 hours’ duration) of spontaneous atrial fibrillation at rates of up to 160 beats/min. These episodes coincided with symptoms. Chest x ray and cardiac imaging were entirely normal.


Figure 1
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Questions

1 What are the most striking abnormalities depicted on the ECG in the figure?
2 What syndrome is associated with the characteristic features shown in the ECG?
3 What is the aetiology of this syndrome?
4 What are the associations and sequalae of this condition?
5 What treatments are indicated in this patient?

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Answers

Short answers

1 The ECG shows left anterior fascicular block: a right bundle branch block pattern in the precordial leads (C1-C3) with "coved" ST segment elevation in C1 and C2 and T wave inversion in C1 and C2, together with "saddle back" ST elevation in C3.
2 Brugada syndrome.
3 This is a genetic disorder characterised by a mutation in the "sodium channel" within the cardiac myocyte.
4 Patients are predisposed to malignant ventricular rhythms and sudden cardiac death.
5 Treatment is directed to preventing ventricular fibrillation or ventricular tachycardia, either medically or with device therapy. (This case was complicated by paroxysmal atrial fibrillation. Initially a rate control strategy was used, with subsequent referral for assessment for pulmonary vein isolation and the implantation of an intracardiac defibrillator.)

Long answers
Abnormalities
The ECG shows a right bundle branch block pattern in the precordial leads (C1-C3) with "coved" ST segment elevation in C1 and C2. T wave inversion in C1 and C2, together with "saddle back" ST elevation in C3, is typical of type 1 pattern of the Brugada phenotype. Type 2 and type 3 phenotypes are characterised by a saddle shaped ST segment, usually in lead C2; they are less specific and have less prognostic value in asymptomatic individuals. The QT interval is normal on this ECG.

Brugada syndrome
The likely diagnosis from these ECG features is type 1 Brugada syndrome. First described in 1992,1 the syndrome comprises ECG features of right bundle branch block and three recognised forms of ST segment elevation in the precordial chest leads.2 Brugada syndrome is an ion channel disease, inherited in an autosomal dominant fashion. Among patients with symptoms, the syndrome is thought to be responsible for 4-12% of all sudden cardiac deaths and for at least 20% of sudden deaths in patients with structurally normal hearts.3

Sequelae and treatments
Patients with Brugada syndrome, who have structurally normal hearts, have a propensity for sudden death due to ventricular arrhythmias. The true incidence of this syndrome is unknown due to concealed forms, but it seems to be more common among South East Asians.3

In some patients the ECG is normal and will show the typical features only after challenge with certain anti-arrhythmic drugs (flecainide, ajmaline, procainamide). The associated rhythm disturbance with the syndrome is usually characterised by polymorphic ventricular tachycardia that can decay into ventricular fibrillation and sudden death.

The arrythmogenic substrate in Brugada syndrome does not seem to be confined to the ventricles.4 Atrial arrhythmias have an incidence of 6% to 38%, and spontaneous atrial fibrillation is the most common.5 6 Brugada syndrome patients with documented ventricular fibrillation have a higher incidence of spontaneous atrial fibrillation.7 8 Recent studies have shown that variants of the SCN5A gene (associated with Brugada syndrome,9 10 certain long QT syndromes, and ventricular fibrillation11) may also predispose patients to atrial fibrillation.12

In patients without symptoms whose ECG shows right bundle branch block and saddle back ST elevation, the long term prognosis seems to be good.13 14 These patients should be asked about any family history of sudden or unexplained death, as this may determine whether to recommend an implantable defibrillator. For ventricular arrhythmias, an implantable cardiac-defibrillator is currently recommended.15

The management of atrial fibrillation in patients with Brugada syndrome is challenging because of the potential pro-arrhythmic actions of drug. The syndrome results from mutations of the cardiac sodium channels. Most drugs prescribed to prevent atrial fibrillation will act either via these ion channels or in a way that might prolong the QT interval. At present, pulmonary vein isolation seems to be the treatment of choice, particularly in patients whose symptoms remain despite adequate rate control.16 In this case the strategy was initially rate control of the patient’s atrial fibrillation. Despite using two different classes of agent (verapamil and β blockers) , he remained symptomatic. He has now been referred for pulmonary vein isolation.

It is important to recognise the electrocardiographic phenotype of Brugada syndrome. This syndrome should be considered as an unusual, but ominous, cause of lone atrial fibrillation.

Cite this as: BMJ 2009;338:a3087

Competing interests: None declared.

Provenance and peer review: Not commissioned; externally peer reviewed.

Patient consent obtained.

References

  1. Brugada P, Brugada J. Right bundle branch block, persistent ST segment elevation and sudden cardiac death: a distinct clinical and electrocardiographic syndrome. A multicenter report. J Am Coll Cardiol 1992;20:1391-6.[Abstract]
  2. Donohue D, Tehrani F, Jamehdor R, Lam C, Movahed M-R. The prevalence of Brugada ECG in adult patients in a large university hospital in the western United States. Am Heart Hosp J 2007;6:48-50.
  3. Juang JM, Huang SK. Brugada syndrome—an under-recognized electrical disease in patients with sudden cardiac death. Cardiology 2004;101:157-69.[CrossRef][Web of Science][Medline]
  4. Yamada T, Watanabe I, Okumura Y, Takagi Y, Okubo K, Hashimoto K, et al. Atrial electrophysiological abnormality in patients with Brugada syndrome assessed by P-wave signal-averaged ECG and programmed atrial stimulation. Circ J 2006;70:1574-9.[CrossRef][Web of Science][Medline]
  5. Letsas KP, Sideris A, Efremidis M, Pappas LK, Gavrielatos G, Filippatos GS, et al. Prevalence of paroxysmal atrial fibrillation in Brugada syndrome: a case series and a review of the literature. J Cardiovasc Med (Hagerstown) 2007;8:803-6.[Medline]
  6. Francis J, Antzelevitch C. Atrial fibrillation and Brugada syndrome. J Am Coll Cardiol 2008;51:1149-53.[Abstract/Free Full Text]
  7. Morita H, Kusano-Fukushima K, Nagase S, Fujimoto Y, Hisamatsu K, Fujioh H, et al. Atrial fibrillation and atrial vulnerability in patients with Brugada syndrome. J Am Coll Cardiol 2002;40:1437-44.[Abstract/Free Full Text]
  8. Kusano KF, Taniyama M, Nakamura K, Miura D, Banba K, Nagare S, et al. Atrial fibrillation in patients with Brugada syndrome: relationships of gene mutation, electrophysiology, and clinical backgrounds. J Am Coll Cardiol 2008;51:1169-75.[Abstract/Free Full Text]
  9. Potet F, Mabo P, Le Coq G, Probst V, Schott JJ, Airaud F, et al. Novel brugada SCN5A mutation leading to ST segment elevation in the inferior or the right precordial leads. J Cardiovasc Electrophysiol 2003;14:200-3.[Web of Science][Medline]
  10. Pfahnl AE, Viswanathan PC, Weiss R, Shang LL, Sanyal S, Shusterman V, et al. A sodium channel pore mutation causing Brugada syndrome. Heart Rhythm 2007;4:54-5.[CrossRef][Web of Science][Medline]
  11. Chen Q, Kirsch GE, Zhang D, Brugada R, Brugada J, Potenza D, et al. Genetic basis and molecular mechanism for idiopathic ventricular fibrillation. Nature 1998;392:293-6.[CrossRef][Medline]
  12. Darbar D, Kannankeril PJ, Donahue BS, Kucera G, Stubblefield T, Haines JL, et al. Cardiac sodium channel (SCN5A) variants associated with atrial fibrillation. Circulation 2008;117:1927-35.[Abstract/Free Full Text]
  13. Eckardt L, Probst V, Smits JP, Bahr ES, Wolpert C, Schimpf R, et al. Long-term prognosis of individuals with right precordial ST-segment-elevation Brugada syndrome. Circulation 2005;111:257-63.[Abstract/Free Full Text]
  14. Jumtilla MJ, Raatikainen MJ, Karjalainen J, Kauma H, Kesaniemi YA, Huikuri HV. Prevalence and prognosis of subjects with Brugada-type ECG pattern in a young and middle aged Finnish population. Eur Heart J 2004;25:874-8.[Abstract/Free Full Text]
  15. Sarkozy A, Boussy T, Kourgiannides G, Chierchia GB, Richter S, De Potter T, et al. Long-term follow-up of primary prophylactic implantable cardioverter-defibrillator therapy in Brugada syndrome. Eur Heart J 2007;28:334-44.[Abstract/Free Full Text]
  16. Yamada T, Yoshida Y, Tsuboi N, Murakami Y, Okada T, McElderry HT, et al. Efficacy of pulmonary vein isolation in paroxysmal atrial fibrillation patients with a Brugada electrocardiogram. Circ J 2008;72:281-6.[CrossRef][Web of Science][Medline]

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