The ajmaline challenge in Brugada syndrome: diagnostic impact, safety, and recommended protocol.
OBJECTIVE
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.


RESULTS
During a period of 60 months, 158 patients underwent the ajmaline test in our institution. Ajmaline was given intravenously in fractions (10mg every two minutes) up to a target dose of 1mg/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.


CONCLUSIONS
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.
Rolf
Sascha
S
Hospital of the Westfälische Wilhelms-University, Department of Cardiology and Angiology, Institute for Arteriosclerosis Research, Münster, Germany. srolf@uni-muenster.de
Bruns
Hans-Jürgen
HJ
Wichter
Thomas
T
Kirchhof
Paulus
P
Ribbing
Michael
M
Wasmer
Kristina
K
Paul
Matthias
M
Breithardt
Günter
G
Haverkamp
Wilhelm
W
Eckardt
Lars
L
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000404:Ajmaline / Q000008:administration & dosage / Q000009:adverse effects; D000889:Anti-Arrhythmia Agents / Q000008:administration & dosage / Q000009:adverse effects; D002037:Bundle-Branch Block / Q000175:diagnosis*; D002648:Child; D002985:Clinical Protocols; D016757:Death, Sudden, Cardiac / Q000209:etiology*; D004305:Dose-Response Relationship, Drug; D004562:Electrocardiography / Q000379:methods; D006801:Humans; D007262:Infusions, Intravenous; D008875:Middle Aged; D013575:Syncope / Q000209:etiology*; D013577:Syndrome
D000889:Anti-Arrhythmia Agents; D000404:Ajmaline