title: Second coupling interval of nonsustained ventricular tachycardia to distinguish malignant from benign outflow tract ventricular tachycardias.
abstract: BACKGROUND
  Idiopathic ventricular tachycardia (VT) originating from the outflow tract (OT) usually is considered a benign condition. In rare cases, patients with OT-VT suffer from syncope or even sudden cardiac death. OT-VT is frequently preceded by nonsustained VT (NSVT).
  
  
  OBJECTIVE
  The purpose of this study was to clarify if the ECG parameters of NSVTs could differentiate malignant from benign OT-VT.
  
  
  METHODS
  We retrospectively evaluated patients without structural heart disease who had documented OT-NSVT on ECG. ECG parameters were compared between patients with syncope, aborted sudden cardiac death, or ventricular fibrillation (malignant group, n = 36) and patients without syncope (benign group, n = 40).
  
  
  RESULTS
  There were no differences with regard to age and gender between the malignant and benign groups. On analysis of NSVT, the first coupling interval (CI) of NSVT was comparable between the 2 groups (458 ± 87 ms vs 485 ± 95 ms, P = .212). However, the second CI of NSVT beats was significantly shorter in the malignant group (313 ± 58 ms vs 385 ± 83 ms, P < .0001). During 48-month follow-up, the benign group had a significantly lower recurrence of clinical VT than the malignant group (P = .046). The malignant group frequently had more than 1 focus of VT, whereas the benign group showed only a single focus (1.82 vs 1.09, P = .023).
  
  
  CONCLUSIONS
  The second CI of NSVT in the malignant group was significantly shorter than that of the benign OT-VT group. Careful measurement of the second CI of NSVT may help identify the malignant form of OT-VT, enabling early treatment to prevent future cardiac events.
authors.affiliation: Heart Institute, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Yoo Ri
authors.initials: YR
authors.lastname: Kim
authors.affiliation: Heart Institute, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea. Electronic address: gbnam@amc.seoul.kr.
authors.forename: Gi-Byoung
authors.initials: GB
authors.lastname: Nam
authors.affiliation: Heart Institute, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Chang Hee
authors.initials: CH
authors.lastname: Kwon
authors.affiliation: Heart Institute, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Woo Seok
authors.initials: WS
authors.lastname: Lee
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, Korea.
authors.forename: Yong-Giun
authors.initials: YG
authors.lastname: Kim
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Pusan National University Yangsan Hospital, Pusan, Korea.
authors.forename: Ki-Won
authors.initials: KW
authors.lastname: Hwang
authors.affiliation: Heart Institute, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Jun
authors.initials: J
authors.lastname: Kim
authors.affiliation: Heart Institute, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: Kee-Joon
authors.initials: KJ
authors.lastname: Choi
authors.affiliation: Heart Institute, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors.forename: You-Ho
authors.initials: YH
authors.lastname: Kim
mesh_terms: D000328:Adult; D017115:Catheter Ablation / Q000379:methods / Q000401:mortality; D015331:Cohort Studies; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D017147:Defibrillators, Implantable; D003937:Diagnosis, Differential; D004562:Electrocardiography; D005260:Female; D006801:Humans; D015994:Incidence; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D016019:Survival Analysis; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy; D014694:Ventricular Outflow Obstruction / Q000175:diagnosis; D018879:Ventricular Premature Complexes / Q000175:diagnosis* / Q000401:mortality / Q000628:therapy
keywords: Electrocardiography; Outflow tract; Ventricular tachycardia