title: Sentinel symptoms in patients with unexplained cardiac arrest: from the cardiac arrest survivors with preserved ejection fraction registry (CASPER).
abstract: BACKGROUND
  Warning symptoms may provide an opportunity to diagnose genetic disorders leading to preventative therapy. We explored the symptom history of patients with apparently unexplained cardiac arrest to determine the frequency of sentinel symptoms.
  
  
  METHODS
  Patients with apparently unexplained cardiac arrest and no evident cardiac disease underwent systematic clinical evaluation. Patients and first-degree relatives were interviewed to determine the presence of cardiac symptoms, and those with syncope underwent 2 structured Calgary Syncope Score questionnaires to determine the probable mechanism of syncope.
  
  
  RESULTS
  One hundred consecutive cardiac arrest patients (age 43.0 ± 13.4 years, 60% male) and 63 first-degree relatives (age 37.6 ± 16.3 years, 54% female) were enrolled. Previous cardiac symptoms were present in 69% of cardiac arrest patients compared to 43% of family members (P = 0.001). Prior syncope was present in 26% of cardiac arrest patients, compared to 22% of family members (P = 0.59). Twenty-four of 25 cardiac arrest patients who completed the syncope questionnaires had a syncope versus seizure score <1 favoring syncope. The area under the receiver operator curve (ROC) for the syncope mechanism score was 0.79 for identifying patients with subsequent cardiac arrest (95% CI, 0.6328-0.9395, P = 0.004). A score of ≤-2 had a sensitivity of 68% and specificity of 85%. Thirty percent of patients with a proven genetic cause had preceding syncope versus 19% in patients with noninherited or idiopathic causes (P = 0.032).
  
  
  CONCLUSIONS
  Syncope that may represent a sentinel event is present in a modest proportion of patients and family members, and is often suggestive of an arrhythmia.
authors.affiliation: University of Western Ontario, London, Ontario, Canada Hamilton Health Sciences Center, Hamilton, Ontario, Canada. akrahn@uwo.ca
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Krahn
authors.forename: Jeffrey S
authors.initials: JS
authors.lastname: Healey
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Simpson
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: Martin
authors.initials: M
authors.lastname: Gardner
authors.forename: Shubhayan
authors.initials: S
authors.lastname: Sanatani
authors.forename: Santabhanu
authors.initials: S
authors.lastname: Chakrabarti
authors.forename: Raymond
authors.initials: R
authors.lastname: Yee
authors.forename: Allan C
authors.initials: AC
authors.lastname: Skanes
authors.forename: Peter
authors.initials: P
authors.lastname: Leong-Sit
authors.forename: Kamran
authors.initials: K
authors.lastname: Ahmad
authors.forename: Michael H
authors.initials: MH
authors.lastname: Gollob
authors.forename: George J
authors.initials: GJ
authors.lastname: Klein
authors.forename: Lorne J
authors.initials: LJ
authors.lastname: Gula
authors.forename: Robert S
authors.initials: RS
authors.lastname: Sheldon
mesh_terms: D000328:Adult; D002170:Canada / Q000453:epidemiology; D005260:Female; D020022:Genetic Predisposition to Disease; D006323:Heart Arrest / Q000453:epidemiology* / Q000235:genetics / Q000401:mortality / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010375:Pedigree; D010641:Phenotype; D011379:Prognosis; D011446:Prospective Studies; D012372:ROC Curve; D012042:Registries; D018570:Risk Assessment; D012307:Risk Factors; D018571:Sentinel Surveillance; D013318:Stroke Volume; D011795:Surveys and Questionnaires; D013575:Syncope / Q000453:epidemiology* / Q000235:genetics / Q000401:mortality / Q000503:physiopathology