title: Cardiac sympathetic nerve abnormality predicts ventricular tachyarrhythmic events in patients without conventional risk of sudden death.
abstract: OBJECTIVE
  Patients with structural heart disease, severe left ventricular dysfunction, or history of cardiac arrest are at increased risk of sudden cardiac death. However, a useful marker for predicting sudden cardiac death is not clarified in low-risk patients without those conventional risks. We hypothesized that cardiac sympathetic nerve system (SNS) abnormality would be associated with ventricular tachyarrhythmic events in low-risk patients with ventricular tachycardia (VT).
  
  
  METHODS
  Iodine-123 metaiodobenzylguanidine ((123)I-MIBG) scintigraphy was performed in 50 patients (mean+/-standard deviation, age 54 +/- 16 years, 52% males) with VT who did not have structural heart disease, severe left ventricular dysfunction, or history of cardiac arrest, and SNS activity was assessed from heart/mediastinal (H/M) ratio on delayed images.
  
  
  RESULTS
  Over 11 years of follow-up, three patients had sudden deaths (6%) and nine patients had sustained ventricular tachyarrhythmic events (18%). SNS abnormality, defined as H/M ratio <2.8, was predictive of sudden death or ventricular tachyarrhythmic events (45% in nine of 20 patients with SNS abnormality vs 16.7% in three of 30 patients without SNS abnormality, p = 0.005). After adjustment for potential confounding variables including slight left ventricular dysfunction, SNS abnormality remained independently predictive of ventricular tachyarrhythmic events with a hazard ratio of 5.3 (95% confidence interval = 1.4 to 20.8, p = 0.016).
  
  
  CONCLUSIONS
  SNS abnormality is a readily available and powerful predictor of recurrent ventricular tachyarrhythmic events in patients with VT who did not have conventional risk of sudden cardiac death. (123)I-MIBG scintigraphy can provide prognostic information of VT patients without conventional risk.
authors.affiliation: Division of Cardiology, Department of Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawaku, Tokyo, 142-8666, Japan. hzn01233@s02.itscom.net
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Akutsu
authors.forename: Kyouichi
authors.initials: K
authors.lastname: Kaneko
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Kodama
authors.forename: Hui-Ling
authors.initials: HL
authors.lastname: Li
authors.forename: Mitsuharu
authors.initials: M
authors.lastname: Kawamura
authors.forename: Taku
authors.initials: T
authors.lastname: Asano
authors.forename: Kaoru
authors.initials: K
authors.lastname: Tanno
authors.forename: Akira
authors.initials: A
authors.lastname: Shinozuka
authors.forename: Takehiko
authors.initials: T
authors.lastname: Gokan
authors.forename: Youichi
authors.initials: Y
authors.lastname: Kobayashi
mesh_terms: D019797:3-Iodobenzylguanidine; D000328:Adult; D016757:Death, Sudden, Cardiac; D005260:Female; D006321:Heart / Q000294:innervation*; D006801:Humans; D008297:Male; D011379:Prognosis; D011877:Radionuclide Imaging; D012306:Risk; D013564:Sympathetic Nervous System / Q000002:abnormalities* / Q000503:physiopathology; D017180:Tachycardia, Ventricular / Q000150:complications / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology*; D013997:Time Factors
chemical_list: D019797:3-Iodobenzylguanidine