Ajmaline

Abstract: Asyndrome characterized by ST-segment elevation in right precordial leads (V1 to V3) that is unrelated to ischemia, electrolyte disturbances, or obvious structural heart disease was reported as early as 1953,1 but was first described as a distinct clinical entity associated with a high risk of sudden cardiac death in 1992.2–4⇓⇓ The Brugada syndrome is a familial disease that displays an autosomal dominant mode of transmission, with incomplete penetrance and an incidence ranging between 5 and 66 per 10 000. In regions of Southeast Asia where it is endemic, the clinical presentation of Brugada syndrome is distinguished by a male predominance (8:1 ratio of male:female) and the appearance of arrhythmic events at an average age of 40 years (range: 1 to 77 years).2,5⇓ Although a number of candidate genes are considered plausible, thus far the syndrome has been linked only to mutations in SCN5A , the gene encoding for the α subunit of the sodium channel.6 A number of ambiguities exist concerning the diagnosis of Brugada syndrome. The electrocardiographic signature of the syndrome is dynamic and often concealed, but can be unmasked by potent sodium channel blockers such as flecainide, ajmaline, and procainamide,7 although the specificity of this effect for uncovering patients at risk for sudden death has been an issue of concern. A recent report by Remme et al8 has shown that the number of idiopathic ventricular fibrillation patients diagnosed as having Brugada syndrome is a sensitive function of the diagnostic criteria applied. What are the proper diagnostic criteria for identifying Brugada syndrome? A definitive answer to this question has been out of reach and is the reason for the establishment of a special Arrhythmia Working Group of the European Society of Cardiology that met from August 31 to …

Abstract: Background—There is emerging evidence that localization and elimination of abnormal electric activity in the epicardial right ventricular outflow tract may be beneficial in patients with Brugada sy...

Abstract: Aims The diagnostic ECG pattern in Brugada syndrome (BS) can transiently normalize and may be unmasked by sodium channel blockers such as ajmaline. Proarrhythmic effects of the drug have been well documented in the literature. A detailed protocol for the ajmaline challenge in Brugada syndrome has not yet been described. Therefore, we prospectively studied the risks of a standardized ajmaline test. Methods and results During a period of 60 months, 158 patients underwent the ajmaline test in our institution. Ajmaline was given intravenously in fractions (10 mg every two minutes) up to a target dose of 1 mg/kg. In 37 patients (23%) the typical coved-type ECG pattern of BS was unmasked. During the test, symptomatic VT appeared in 2 patients (1.3%). In all other patients, the drug challenge did not induce VT if the target dose, QRS prolongation >30%, presence/appearance of the typical ECG, or the occurrence of premature ventricular ectopy were considered as end points of the test. A positive response to ajmaline was induced in 2 of 94 patients (2%) with a normal baseline ECG, who underwent evaluation solely for syncope of unknown origin. Conclusion The ajmaline challenge using a protocol with fractionated drug administration is a safe method to diagnose BS. Because of the potential induction of VT, it should be performed under continuous medical surveillance with advanced life-support facilities. Due to the prognostic importance all patients with aborted sudden death or unexplained syncope without demonstrable structural heart disease and family members of affected individuals should presently undergo drug testing for unmasking BS.

Abstract: Brugada syndrome presents in a certain number of patients as an inherited cardiac arrhythmia disorder caused by mutations in the cardiac sodium channel gene SCN5A . Carriers of the disease may develop a variety of cardiac arrhythmias, including supraventricular tachycardias, atrioventricular conduction defects or block, sick sinus syndrome with atrial standstill, and ventricular tachycardia and ventricular fibrillation. The disease is characterized by the lack of structural heart disease and an ECG with a characteristic coved-type ST-segment elevation in leads V1, V2, and V3. Syncopal episodes and paroxysmal palpitations are the only symptoms attributable to the disease that may warn before (aborted) sudden arrhythmic death occurs. General agreement exists that an implantable cardioverter defibrillator must be given to patients with Brugada syndrome resuscitated from ventricular fibrillation. However, controversy exists on how to approach the individual with a Brugada-like ECG who has never developed ventricular fibrillation. For the past 12 years, we have maintained a large database of individuals and patients with a characteristic Brugada-like ECG (all coved type). At the last follow-up (January 2004), we analyzed the status of 724 individuals of whom 547 (75%) had no previous cardiac arrest. A subgroup of 167 asymptomatic individuals was also identified who had no family history of sudden death or Brugada syndrome and were considered fortuitous, isolated cases. The abnormal ECG was identified during the investigation of syncope in 124 individuals, during routine ECG screening in 170 individuals, and during study of family members of patients with the syndrome in 253 individuals. The characteristic ECG was present spontaneously in 391 cases and after pharmacological testing with a sodium channel blocker (usually ajmaline) in 156. Mean age of the 547 individuals was 41±15 years, and 408 were male. During a mean follow-up of 28±42 months, 45 (8%) individuals …