title: Epinephrine infusion in the evaluation of unexplained cardiac arrest and familial sudden death: from the cardiac arrest survivors with preserved Ejection Fraction Registry.
abstract: BACKGROUND
  Epinephrine infusion may unmask latent genetic conditions associated with cardiac arrest, including long-QT syndrome and catecholaminergic polymorphic ventricular tachycardia (VT).
  
  
  RESULTS
  Patients with unexplained cardiac arrest (normal left ventricular function and QT interval) and selected family members from the Cardiac Arrest Survivors with Preserved Ejection Fraction Registry (CASPER) registry underwent epinephrine challenge at doses of 0.05, 0.10, and 0.20 μg/kg per minute. A test was considered positive for long-QT syndrome if the absolute QT interval prolonged by ≥ 30 ms at 0.10 μg/kg per minute and borderline if QT prolongation was 1 to 29 ms. Catecholaminergic polymorphic VT was diagnosed if epinephrine provoked ≥ 3 beats of polymorphic or bidirectional VT and borderline if polymorphic couplets, premature ventricular contractions, or nonsustained monomorphic VT was induced. Epinephrine infusion was performed in 170 patients (age, 42 ± 16 years; 49% men), including 98 patients with unexplained cardiac arrest. Testing was positive for long-QT syndrome in 31 patients (18%) and borderline in 24 patients (14%). Exercise testing provoked an abnormal QT response in 42% of tested patients with a positive epinephrine response. Testing for catecholaminergic polymorphic VT was positive in 7% and borderline in 5%. Targeted genetic testing of abnormal patients was positive in 17% of long-QT syndrome patients and 13% of catecholaminergic polymorphic VT patients.
  
  
  CONCLUSIONS
  Epinephrine challenge provoked abnormalities in a substantial proportion of patients, most commonly a prolonged QT interval. Exercise and genetic testing replicated the diagnosis suggested by the epinephrine response in a small proportion of patients. Epinephrine infusion combined with exercise testing and targeted genetic testing is recommended in the workup of suspected familial sudden death syndromes. Clinical Trial Registration- URL: http://www.clinicaltrials.gov. Unique identifier: NCT00292032.
authors.affiliation: University of British Columbia, Vancouver, BC, Canada. akrahn@mail.ubc.ca
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Krahn
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Healey
authors.forename: Vijay S
authors.initials: VS
authors.lastname: Chauhan
authors.forename: David H
authors.initials: DH
authors.lastname: Birnie
authors.forename: Jean
authors.initials: J
authors.lastname: Champagne
authors.forename: Shubhayan
authors.initials: S
authors.lastname: Sanatani
authors.forename: Kamran
authors.initials: K
authors.lastname: Ahmad
authors.forename: Emily
authors.initials: E
authors.lastname: Ballantyne
authors.forename: Brenda
authors.initials: B
authors.lastname: Gerull
authors.forename: Raymond
authors.initials: R
authors.lastname: Yee
authors.forename: Allan C
authors.initials: AC
authors.lastname: Skanes
authors.forename: Lorne J
authors.initials: LJ
authors.lastname: Gula
authors.forename: Peter
authors.initials: P
authors.lastname: Leong-Sit
authors.forename: George J
authors.initials: GJ
authors.lastname: Klein
authors.forename: Michael H
authors.initials: MH
authors.lastname: Gollob
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Simpson
authors.forename: Mario
authors.initials: M
authors.lastname: Talajic
authors.forename: Martin
authors.initials: M
authors.lastname: Gardner
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D002170:Canada / Q000453:epidemiology; D016009:Chi-Square Distribution; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D004562:Electrocardiography; D004837:Epinephrine / Q000008:administration & dosage; D005080:Exercise Test; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007262:Infusions, Intravenous; D008133:Long QT Syndrome / Q000175:diagnosis* / Q000235:genetics* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D012042:Registries; D013318:Stroke Volume; D017741:Survivors; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000235:genetics* / Q000503:physiopathology; D014662:Vasoconstrictor Agents / Q000008:administration & dosage
chemical_list: D014662:Vasoconstrictor Agents; D004837:Epinephrine