Management of torsades de pointes and features of Brugada syndrome
THE CONTEXT
Treatment of torsades de pointes includes immediate arrhythmia suppression, correction of its cause and prevention of recurrence. The passage also introduces the related genetic disorder Brugada syndrome.
Initial treatment
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Give intravenous magnesium in all cases: 8 mmol over 15 minutes, followed by 72 mmol over 24 hours.
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If magnesium is ineffective, try atrial pacing. Pacing often suppresses the arrhythmia through rate-dependent shortening of the QT interval.
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Intravenous isoprenaline is an alternative to pacing, but it should be avoided in congenital long QT syndromes.
Preventing recurrence
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After initial control, identify and treat the underlying cause or stop medications that predispose to the arrhythmia.
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Long-term pharmacological treatment may be necessary if the cause cannot be corrected or the arrhythmia results from an inherited syndrome.
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Beta-blockers are effective at preventing syncope in congenital long QT syndrome.
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Consider an implantable defibrillator in selected patients, particularly those with extreme QT prolongation greater than 500 milliseconds, a history of syncope or certain high-risk genotypes.
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Left stellate ganglion block may help patients with resistant arrhythmias.
Brugada syndrome
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Brugada syndrome is a related genetic disorder that may present with polymorphic ventricular tachycardia or sudden death.
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Mutations are often found in SCN5A, which encodes a sodium channel expressed in cardiac myocytes.
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The characteristic ECG includes right bundle branch block and ST elevation in V1 and V2, usually without QT prolongation.