title: Spectrum and prognostic significance of arrhythmias on ambulatory Holter electrocardiogram in hypertrophic cardiomyopathy.
abstract: OBJECTIVE
  The goal of this study was to assemble a profile and assess the significance of arrhythmias in a nontertiary-based hypertrophic cardiomyopathy (HCM) cohort.
  
  
  BACKGROUND
  Hypertrophic cardiomyopathy is associated with arrhythmia-related consequences, particularly sudden death. Ventricular tachyarrhythmias on Holter electrocardiograms (ECG) have been reported as markers for sudden death in highly selected HCM populations.
  
  
  METHODS
  We assessed the profile of ventricular and supraventricular ectopy and bradyarrhythmia on ambulatory 24-h Holter ECG and also related these findings to clinical outcome in 178 HCM patients.
  
  
  RESULTS
  Of the 178 study patients, 157 (88%) had premature ventricular complexes (PVCs), including 21 (12%) with >/=500 PVCs, 74 (42%) had couplets, 67 (37%) had supraventricular tachycardia (SVT), and 56 (31%) had nonsustained ventricular tachycardia (NSVT). Mean number of PVCs was 330 +/- 763 (range 1 to 5,435) and increased with age (p < 0.01); NSVT was associated with greater left ventricular hypertrophy (p = 0.01) and severe symptoms (New York Heart Association functional classes III and IV) (p = 0.04); SVT occurred more commonly in patients with outflow obstruction (p = 0.02). Over a follow-up of 5.5 +/- 3.4 years, 11 (6%) patients died suddenly (annual mortality rate, 1.1%) including 5 patients with NSVT. For sudden death, NSVT on Holter ECG had negative and positive predictive values of 95% and 9%, and sensitivity and specificity of 45% and 69%, respectively.
  
  
  CONCLUSIONS
  In this nontertiary-based HCM cohort, ventricular and supraventricular tachyarrhythmias were particularly frequent and demonstrated a broad spectrum on ambulatory (Holter) ECG. Paradoxically, despite such a highly arrhythmogenic substrate, sudden death events proved to be relatively uncommon. Ventricular tachyarrhythmias had a low positive and relatively high negative predictive value for sudden death in this HCM population.
authors.affiliation: Division of Cardiology, and Geriatric Research Education and Clinical Center, Veterans Affairs Medical Center, Minneapolis, Minnesota, USA. adaba001@umn.edu
authors.forename: A Selcuk
authors.initials: AS
authors.lastname: Adabag
authors.forename: Susan A
authors.initials: SA
authors.lastname: Casey
authors.forename: Michael A
authors.initials: MA
authors.lastname: Kuskowski
authors.forename: Andrey G
authors.initials: AG
authors.lastname: Zenovich
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Maron
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018880:Atrial Premature Complexes / Q000175:diagnosis / Q000453:epidemiology; D001919:Bradycardia / Q000175:diagnosis / Q000453:epidemiology*; D016507:Cardiology Service, Hospital; D002312:Cardiomyopathy, Hypertrophic / Q000175:diagnosis / Q000453:epidemiology*; D002648:Child; D002675:Child, Preschool; D015897:Comorbidity; D016757:Death, Sudden, Cardiac / Q000453:epidemiology; D015716:Electrocardiography, Ambulatory; D005260:Female; D005500:Follow-Up Studies; D006764:Hospitals, Community; D006801:Humans; D008297:Male; D008875:Middle Aged; D008910:Minnesota; D012307:Risk Factors; D016019:Survival Analysis; D013617:Tachycardia, Supraventricular / Q000175:diagnosis / Q000453:epidemiology*; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000453:epidemiology*; D018879:Ventricular Premature Complexes / Q000175:diagnosis / Q000453:epidemiology