title: Effect of circadian variability in frequency of premature ventricular complexes on left ventricular function.
abstract: BACKGROUND
  Frequent idiopathic premature ventricular complexes (PVCs) can result in a reversible form of cardiomyopathy.
  
  
  OBJECTIVE
  The purpose of this study was to assess the impact of variability in PVC frequency throughout the day on PVC-induced cardiomyopathy.
  
  
  METHODS
  The subjects of this study were 107 consecutive patients (58 men [54%]; mean age 49.7 ± 15.0 years; left ventricular ejection fraction 50.4% ± 11.4%) referred for ablation of frequent PVCs. All patients underwent 24-hour Holter monitoring before the ablation procedure. The circadian variation in PVC burden was determined and correlated with the presence or absence of cardiomyopathy.
  
  
  RESULTS
  A total of 43 patients (40%) had cardiomyopathy. Patients with cardiomyopathy had an ejection fraction of 38.4% ± 6.9%, a higher PVC burden (28.5% ± 11.5% vs 19.5% ± 10.5%; P = .0001), less variability in circadian PVC distribution (coefficient of variation hourly: 31.5% ± 21% vs 59.8% ± 32.4%; P = .0001), and more frequent interpolated PVCs (20 patients [47%] vs 15 patients [23%]; P = 0.022), and were more frequently asymptomatic than patients without cardiomyopathy (56% vs 19%; P = .0001). In multivariate analysis, consistency in PVC burden throughout the day was an independent predictor of PVC-induced cardiomyopathy (odds ratio 16.3; 95% confidence interval 1.7-155.3; p = 0.015).
  
  
  CONCLUSIONS
  In patients with frequent PVCs, consistency in hourly PVC frequency throughout the day is an independent predictor of PVC-induced cardiomyopathy.
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan.
authors.forename: Hatice Duygu
authors.initials: HD
authors.lastname: Bas
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan.
authors.forename: Kazim
authors.initials: K
authors.lastname: Baser
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan.
authors.forename: John
authors.initials: J
authors.lastname: Hoyt
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan.
authors.forename: Miki
authors.initials: M
authors.lastname: Yokokawa
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan.
authors.forename: Troy
authors.initials: T
authors.lastname: LaBounty
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan.
authors.forename: Fred
authors.initials: F
authors.lastname: Morady
authors.affiliation: Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan. Electronic address: fbogun@med.umich.edu.
authors.forename: Frank
authors.initials: F
authors.lastname: Bogun
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D009202:Cardiomyopathies / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control; D017115:Catheter Ablation / Q000379:methods*; D002940:Circadian Rhythm / Q000502:physiology*; D015716:Electrocardiography, Ambulatory / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D013318:Stroke Volume; D018879:Ventricular Premature Complexes / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery
keywords: Ablation; Cardiomyopathy; Circadian variation; PVC; PVC-induced cardiomyopathy; Predictor of cardiomyopathy; Premature ventricular complexes; Variability