Brugada syndrome is an inherited cardiac channelopathy with potential for life threatening ventricular arrhythmias and sudden cardiac death . Coved ST segment elevation of 2 mm or more with negative T wave in right precordial leads V1 and V2, either spontaneously or after challenge with sodium channel blocker drug is the characteristic ECG finding. Though implantation of an ICD (implantable cardioverter-defibrillator is the main treatment, quinidine for Brugada syndrome is an option worth it in certain situations .
Quinidine is a Class I antiarrhythmic agent which can block Ito and IKr currents. It has been shown to prevent phase II re-entry and ventricular fibrillation in experimental studies on Brugada syndrome. When ventricular fibrillation was inducible at baseline electrophysiology studies, quinidine can render it non inducible in 76% to 88% . Quinidine has been reported to be useful in pediatric patients as an alternative to ICD . It may be useful in the setting of arrhythmic storms and to reduce the number of ICD shocks.
Belhassen B et al prospectively evaluated 25 patients with Brugada syndrome, of which 7 were cardiac arrest survivors and 7 had unexplained syncope . In all 25 patients, ventricular fibrillation could be induced at baseline electrophysiological study. Twenty two of the 25 (88%) were non-inducible on while Quinidine. Long term treatment ranging from 6 to 219 months was given to 19 patients. None had arrhythmic events, though 2 had non arrhythmia related syncope. Side effects occurred in 36% which resolved on drug discontinuation.
Side effects of quinidine like QT prolongation with potential for torsades de pointes, thrombocytopenia, diarrhea, esophagitis, allergic reactions and aggravation of sinus node dysfunction have to be kept in mind. Moreover it is not freely available in all countries .
Quinine instead of quinidine
Since quinidine is not freely available, people have used quinine which is used as an antimalarial drug . It was successful in controlling electrical storm in a ten year old child with Brugada syndrome. Intravenous quinine, a diastereomer of quinidine was used in this case as quinidine was not available.