aVR sign in Brugada syndrome
A prominent R wave in lead aVR (aVR sign in Brugada syndrome) was suggested as marker for development of life threatening arrhythmic events in Brugada syndrome by Babai Bigi MA and associates [1]. They proposed that a prominent final R wave in lead aVR may indicate more right ventricular conduction delay and hence more electrical heterogeneity, which can cause a higher risk of arrhythmia.
R wave amplitude of 0.3 mV or more OR R/q 0.75 or more have been considered as significant. Over three fourths of recurrent arrhythmic events were in those with aVR sign. More than eighty percent of Brugada syndrome patients with the sign in their study had arrhythmic events on follow up. At the same time only about a quarter of those without aVR sign had arrhythmic events on follow up.
R’/S ratio in aVR (aVR sign) has been associated with AA genotype carriers compared to G allele carriers in Brugada syndrome with SCN5A mutations [2]. But a study of 200 probands of Brugada syndrome of which one third were symptomatic, did not find significant correlation between symptomatic status and aVR sign [3]. In that study only significant correlation with symptoms was for the QRS duration.
References
- Babai Bigi MA, Aslani A, Shahrzad S. Heart Rhythm 2007; 4: 1009-1012.
- Lizotte E, Junttila MJ, Dube MP, Hong K, Benito B, DE Zutter M, Henkens S, Sarkozy A, Huikuri HV, Towbin J, Vatta M, Brugada P, Brugada J, Brugada R. Genetic modulation of brugada syndrome by a common polymorphism. J Cardiovasc Electrophysiol. 2009 Oct;20(10):1137-41.
- Junttila MJ, Brugada P, Hong K, Lizotte E, DE Zutter M, Sarkozy A, Brugada J, Benito B, Perkiomaki JS, Mäkikallio TH, Huikuri HV, Brugada R. Differences in 12-lead electrocardiogram between symptomatic and asymptomatic Brugada syndrome patients. J Cardiovasc Electrophysiol. 2008 Apr;19(4):380-3.