0332 : QUIDAM Study: assessment of hydroquinidine therapy in the management of Brugada syndrome patients at high arrhythmic risk and implanted with an ICD

Background During last decades, the knowledge in pathophysiological mechanisms of Brugada Syndrome improved. ICD implantation is the only effective treatment to decrease arrhythmic mortality in high-risk patients. Based on experimental and clinical data hydroquinidine seems to be a promising alternative for the management of ventricular arrhythmia and SCD but need to be evaluated. Methods Fifty patients were included in this French multicentric, randomised, double-blind study. Hydroquinidine or placebo treatment was given during two 18 months cross-over phases. Arrhythmic events, ECG parameters and clinical events were evaluated. Results Twenty-six (52%) patients completed the study. Thirty-four (68%) presented side effects, mainly gastrointestinal, related to hydroquinidine therapy in whom 13 had to stopped. One appropriate ICD shock, one ventricular fibrillation with self-resolution and one inappropriate ICD shock occurred in absence of hydroquinidine therapy. Not one of these event occurred under hydroquinidine. No statistical analysis has been done, regarding this low number of arrhythmic events. Hydroquinidine, at short (3 hours after first taking) or long-term, significantly lengthen QT interval, QTc (respectively 404 vs 417sm and 409 vs 433ms), Tpe and Tpe max (respectively 94,8 vs 106,6 ms and 89,4 vs 107,7ms) without any change on J-point elevation nor Tpe/QTc ratio. QTc interval was significantly longer (433 vs 417ms) during long than short-term treatment without any other effect on ECG parameters. Conclusion High rates of hydroquinidine side effects and low number of arrhythmic events give difficulties to conduct large studies to prove its efficiency in Brugada Syndrome. Hydroquinidine lengthens and increases the repolarisation dispersal, with electrocardiographic effects generally similar during short and long-term treatment. These considerations should not stop its use in daily clinical practice, especially for management of electrical storms. The author hereby declares no conflict of interest Download full-size image Figure . Flow chart of QUIDAM study.