title: Association between frequency of atrial and ventricular ectopic beats and biventricular pacing percentage and outcomes in patients with cardiac resynchronization therapy.
abstract: BACKGROUND
  A high percentage of biventricular pacing is required for optimal outcome in patients treated with cardiac resynchronization therapy (CRT), but the influence of ectopic beats on the success of biventricular pacing has not been well established.
  
  
  OBJECTIVE
  This study sought to determine if increased ectopic beats reduce the chance of high biventricular pacing percentage and are associated with subsequent adverse outcomes.
  
  
  METHODS
  From the MADIT-CRT (Multicenter Automatic Defibrillator Implantation Trial With Cardiac Resynchronization Therapy), 801 patients with an implanted CRT-defibrillator device with data available on biventricular pacing percentage and pre-implantation 24-h Holter recordings were included. Using logistic regression, we estimated the influence of ectopic beats on the percentage of biventricular pacing. Reverse remodeling was measured as reductions in atrial and left ventricular end-systolic volumes (LVESV) at 1 year. Cox models were used to assess the influence of ectopic beats on the outcomes of heart failure (HF) or death, ventricular tachyarrhythmias (VTAs), and death.
  
  
  RESULTS
  In the pre-implantation Holter recording, ectopic beats accounted for a mean 3.2 ± 5.5% of all beats. The probability of subsequent low biventricular pacing percentage (<97%) was increased 3-fold (odds ratio: 3.37; 95% confidence interval: 1.74 to 6.50; p < 0.001) in patients with 0.1% to 1.5% ectopic beats and 13-fold (odds ratio: 13.42; 95% confidence interval: 7.02 to 25.66; p < 0.001) in patients with >1.5% ectopic beats compared with those with <0.1% ectopic beats. Patients with ≥0.1% ectopic beats had significantly less reverse remodeling (percent reduction in LVESV 31 ± 15%) than patients with <0.1% ectopic beats (percent reduction in LVESV 39 ± 14%; p < 0.001). The risk of HF/death and VTA was increased significantly in those with 0.1% to 1.5% ectopic beats (hazard ratio: 3.13 and 1.84, respectively) and for >1.5% ectopic beats (hazard ratio: 2.38 and 2.74, respectively).
  
  
  CONCLUSIONS
  Relatively low frequencies of ectopic beats (≥0.1%) dramatically increase the probability of low biventricular pacing (<97%), with reduced CRT efficacy by less reverse remodeling and higher risk of HF/death and VTA. This supports pre-implantation Holter monitoring of patients selected for CRT for optimal outcome. (MADIT-CRT: Multicenter Automatic Defibrillator Implantation With Cardiac Resynchronization Therapy; NCT00180271).
authors.affiliation: Heart Research Follow-up Program, University of Rochester Medical Center, Rochester, New York; Department of Cardiology, Gentofte Hospital, Hellerup, Denmark. Electronic address: mruwald@hotmail.com.
authors.forename: Martin H
authors.initials: MH
authors.lastname: Ruwald
authors.affiliation: Arrhythmia Institute, Valley Health System of New York and New Jersey, New York, New York and Ridgewood, New Jersey.
authors.forename: Suneet
authors.initials: S
authors.lastname: Mittal
authors.affiliation: Heart Research Follow-up Program, University of Rochester Medical Center, Rochester, New York; Department of Cardiology, Gentofte Hospital, Hellerup, Denmark.
authors.forename: Anne-Christine
authors.initials: AC
authors.lastname: Ruwald
authors.affiliation: Heart Research Follow-up Program, University of Rochester Medical Center, Rochester, New York.
authors.forename: Mehmet K
authors.initials: MK
authors.lastname: Aktas
authors.affiliation: Cardiology Division, Department of Medicine and Duke Clinical Research Institute, Duke University Medical Center, Durham, North Carolina.
authors.forename: James P
authors.initials: JP
authors.lastname: Daubert
authors.affiliation: Heart Research Follow-up Program, University of Rochester Medical Center, Rochester, New York.
authors.forename: Scott
authors.initials: S
authors.lastname: McNitt
authors.affiliation: Texas Cardiac Arrhythmia Institute, Austin, Texas.
authors.forename: Amin
authors.initials: A
authors.lastname: Al-Ahmad
authors.affiliation: Department of Cardiology, Gentofte Hospital, Hellerup, Denmark.
authors.forename: Christian
authors.initials: C
authors.lastname: Jons
authors.affiliation: Heart Research Follow-up Program, University of Rochester Medical Center, Rochester, New York.
authors.forename: Valentina
authors.initials: V
authors.lastname: Kutyifa
authors.affiliation: Arrhythmia Institute, Valley Health System of New York and New Jersey, New York, New York and Ridgewood, New Jersey.
authors.forename: Jonathan S
authors.initials: JS
authors.lastname: Steinberg
authors.affiliation: Division of Cardiovascular Medicine, Stanford University, Stanford, California.
authors.forename: Paul
authors.initials: P
authors.lastname: Wang
authors.affiliation: Heart Research Follow-up Program, University of Rochester Medical Center, Rochester, New York.
authors.forename: Arthur J
authors.initials: AJ
authors.lastname: Moss
authors.affiliation: Heart Research Follow-up Program, University of Rochester Medical Center, Rochester, New York.
authors.forename: Wojciech
authors.initials: W
authors.lastname: Zareba
mesh_terms: D017677:Age Distribution; D000368:Aged; D018880:Atrial Premature Complexes / Q000453:epidemiology / Q000209:etiology*; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects* / Q000379:methods; D016001:Confidence Intervals; D017147:Defibrillators, Implantable / Q000009:adverse effects*; D004452:Echocardiography / Q000379:methods; D015716:Electrocardiography, Ambulatory / Q000379:methods; D005260:Female; D006333:Heart Failure / Q000175:diagnosis / Q000401:mortality / Q000628:therapy; D006801:Humans; D015994:Incidence; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D011379:Prognosis; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012720:Severity of Illness Index; D017678:Sex Distribution; D015996:Survival Rate; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000401:mortality / Q000628:therapy*; D016896:Treatment Outcome; D018879:Ventricular Premature Complexes / Q000453:epidemiology / Q000209:etiology*
keywords: Holter monitoring; biventricular pacing; cardiac resynchronization therapy; ectopic beats; prognosis; reverse remodeling