600Incidence, clinical features and management of arrhythmias during ajmaline challenge in patients with suspected Brugada Syndrome

Abstract

Background: Brugada Syndrome (BS) is characterised by an increased risk of sudden death. Intravenous administration of ajmaline is an established tool to unmask the diagnostic ECG pattern in patients with suspected BS. Purpose: Ajmaline challenge (AC) is considered a safe procedure but life-threatening arrhythmias (LTAs) are described. The purpose of this study is to assess the incidence of arrhythmias during AC in a large consecutive serie of patients and to value the characteristics of these patients and the treatment of these arrhythmias. Methods: 260 patients (184 males, mean age 43±15 years; ) were submitted to AC in 2 medical centers. Ajmaline (1 mg/Kg) was administered intravenously over a 5-10 minutes period. Ajmaline infusion was discontinued before reaching the target dose if QRS prolongation exceeded 30% compared to baseline or when frequent (> 10) premature ventricular complexes (PVCs) or type 1 Brugada ECG occured. Results: The AJ test was positive in 98 (38%) patients (70 men, mean age 46±13 years). 202 (78%) patients received the maximal dose of ajmaline according to their body weight. During AC, 38 (15%) patients developed isolated or coupled PVCs: in 33 out of 38 (87%)patients, the arrhythmias were abolished by the interruption of the test, in 1 patient PVCs persisted after the discontinuance of the test and they were stopped by the infusion of isoproterenol (IPN) ; 4 patients developed a ventricular tachicardia (VT): 2 patients a not-sustained VT that spontaneously ceased, 1 patient a sustained VT that required cardiopulmonary resuscitation (CPR) for 15 minutes and was effectively treated with sodium bicarbonate and IPN infusion, and 1 patient a sustained VT in which CPR with current DC shocks, adrenaline, sodium bicarbonate and IPN were ineffective and the patient was treated with an extracorporeal membrane oxygenation (ECMO). Although, this patient survived without neurological damages. Gender and age are not predictors of arrhythmias during AC but only a positive test is a predictor of an arrhythmogenic risk in AC (table 1). Conclusions: PVCs are not a rare event during AC but interruption of the test is resolutive in most of cases. On the contrary, LTAs are rare during AC and generally have a positive outcome. When it happens a cardiac arrest refractory to ordinary CPR manoeuvers, advanced CPR techniques as ECMO should always be checked.