title: High prevalence of concealed Brugada syndrome in patients with atrioventricular nodal reentrant tachycardia.
abstract: BACKGROUND
  Atrioventricular nodal reentrant tachycardia (AVNRT) may coexist with Brugada syndrome (BrS).
  
  
  OBJECTIVE
  The present study was designed to determine the prevalence of drug-induced type 1 Brugada ECG pattern (concealed BrS) in patients presenting with clinical spontaneous AVNRT and to investigate their electrocardiographic, electrophysiological, and genetic characteristics.
  
  
  METHODS
  Ninety-six consecutive patients without any sign of BrS on baseline electrocardiogram undergoing electrophysiological study and ablation for symptomatic, drug-resistant AVNRT and 66 control subjects underwent an ajmaline challenge to unmask BrS. Genetic screening was performed in 17 patients displaying both AVNRT and BrS.
  
  
  RESULTS
  A concealed BrS electrocardiogram was uncovered in 26 of 96 patients with AVNRT (27.1%) and in 3 of 66 control subjects (4.5%) (P ≤ .001). Patients with concealed BrS were predominantly female patients (n=23 [88.5%] vs n=44 [62.9%], P = .015), had higher prevalence of chest pain (n=10 [38.5%] vs n=13 [18.6%], p=0.042), migraine headaches (n=10 [38.5%] vs n=10 [14.2%], p=0.008), and drug-induced initiation and/or worsening of duration and/or frequency of AVNRT (n=4 [15.4%] vs n=1 [1.4%], p=0.006) as compared to patients with AVNRT without BrS. Genetic screening identified 19 mutations or rare variants in 13 genes in 13 of 17 patients with both AVNRT and BrS (yield = 76.5%). Ten of these 13 genotype-positive patients (76.9%) harbored genetic variants known or suspected to cause a loss of function of cardiac sodium channel current (SCN5A, SCN10A, SCN1B, GPD1L, PKP2, and HEY2).
  
  
  CONCLUSIONS
  Our results suggest that spontaneous AVNRT and concealed BrS co-occur, particularly in female patients, and that genetic variants that reduce sodium channel current may provide a mechanistic link between AVNRT and BrS and predispose to expression of both phenotypes.
authors.affiliation: Department of Cardiology, Ege University School of Medicine, Izmir, Turkey. Electronic address: can.hasdemir@yahoo.com.
authors.forename: Can
authors.initials: C
authors.lastname: Hasdemir
authors.affiliation: Department of Cardiology, Ege University School of Medicine, Izmir, Turkey.
authors.forename: Serdar
authors.initials: S
authors.lastname: Payzin
authors.affiliation: Department of Cardiology, Ege University School of Medicine, Izmir, Turkey.
authors.forename: Umut
authors.initials: U
authors.lastname: Kocabas
authors.affiliation: Department of Cardiology, Ege University School of Medicine, Izmir, Turkey.
authors.forename: Hatice
authors.initials: H
authors.lastname: Sahin
authors.affiliation: Department of Cardiology, Ege University School of Medicine, Izmir, Turkey.
authors.forename: Nihal
authors.initials: N
authors.lastname: Yildirim
authors.affiliation: St. Jude Medical, Izmir, Turkey.
authors.forename: Alpay
authors.initials: A
authors.lastname: Alp
authors.affiliation: Tepecik Teaching and Research Hospital, Izmir, Turkey.
authors.forename: Mehmet
authors.initials: M
authors.lastname: Aydin
authors.affiliation: Masonic Medical Research Laboratory, Utica, New York.
authors.forename: Ryan
authors.initials: R
authors.lastname: Pfeiffer
authors.affiliation: Masonic Medical Research Laboratory, Utica, New York.
authors.forename: Elena
authors.initials: E
authors.lastname: Burashnikov
authors.affiliation: Masonic Medical Research Laboratory, Utica, New York.
authors.forename: Yuesheng
authors.initials: Y
authors.lastname: Wu
authors.affiliation: Masonic Medical Research Laboratory, Utica, New York.
authors.forename: Charles
authors.initials: C
authors.lastname: Antzelevitch
mesh_terms: D000328:Adult; D000404:Ajmaline / Q000494:pharmacology*; D053840:Brugada Syndrome / Q000139:chemically induced / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics / Q000503:physiopathology; D017115:Catheter Ablation / Q000379:methods*; D004562:Electrocardiography / Q000379:methods; D022062:Electrophysiologic Techniques, Cardiac / Q000379:methods; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D062554:NAV1.5 Voltage-Gated Sodium Channel / Q000235:genetics; D062559:NAV1.8 Voltage-Gated Sodium Channel / Q000235:genetics; D015995:Prevalence; D013611:Tachycardia, Atrioventricular Nodal Reentry / Q000175:diagnosis / Q000453:epidemiology / Q000235:genetics / Q000503:physiopathology / Q000601:surgery; D014481:United States / Q000453:epidemiology; D061567:Voltage-Gated Sodium Channel Blockers / Q000494:pharmacology; D062547:Voltage-Gated Sodium Channel beta-1 Subunit / Q000235:genetics
chemical_list: D062554:NAV1.5 Voltage-Gated Sodium Channel; D062559:NAV1.8 Voltage-Gated Sodium Channel; C568317:SCN10A protein, human; C470379:SCN1B protein, human; C568320:SCN5A protein, human; D061567:Voltage-Gated Sodium Channel Blockers; D062547:Voltage-Gated Sodium Channel beta-1 Subunit; D000404:Ajmaline
keywords: Atrioventricular nodal reentrant tachycardia; Brugada syndrome; Genetics; Supraventricular tachycardia