title: The Burden and Morphology of Premature Ventricular Contractions and their Impact on Clinical Outcomes in Patients Receiving Biventricular Pacing in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT).
abstract: BACKGROUND
  Premature ventricular contractions (PVCs) frequently occur in patients with left ventricular dysfunction. However, there are limited data regarding the burden and morphologic characteristics of PVCs in patients receiving cardiac resynchronization therapy.
  
  
  RESULTS
  Patients enrolled in the Multicenter Automatic Defibrillator Implantation Trial-Cardiac Resynchronization Therapy (MADIT-CRT) with >5000 PVCs on a predevice implant 12-lead, 24-hour Holter were identified. The putative PVC site of origin for the most dominant PVC was characterized and their effects on clinical outcomes were evaluated. A total of 146 patients were identified to have >5000 PVCs on Holter of which 75 (51%) had PVCs originating from a non-outflow tract site. Other sites included the left ventricular outflow tract (LVOT), right ventricular outflow tract (RVOT), and the sinus of Valsalva. In multivariate analysis, the risk for HF/Deatd was similar in patients with Outflow tract PVCs when compared to patients with Non-outflow tract PVCs (HR 1.4, 95% CI 0.7-2.8, P = 0.3). The degree of echocardiographic reverse remodeling was similar in patients with outflow tract versus Non-outflow tract PVCs. One-third of patients with nonischemic cardiomyopathy were found to have PVCs originating from the RVOT.
  
  
  CONCLUSIONS
  In patients with mild symptoms of heart failure, there is no difference in the risk of HF or death in patients with outflow versus non-outflow tract PVCs. One-third of patients with NICM have frequent PVCs originating from the RVOT.
authors: University of Rochester Medical Center, Rochester, NY.
authors: Mehmet K
authors: MK
authors: Aktas
authors: Arrhythmia Institute, Valley Health System, Columbia University College of Physicians and Surgeons, New York, NY.
authors: Suneet
authors: S
authors: Mittal
authors: University of Rochester Medical Center, Rochester, NY.
authors: Valentina
authors: V
authors: Kutyifa
authors: University of Rochester Medical Center, Rochester, NY.
authors: Scott
authors: S
authors: McNitt
authors: University of Rochester Medical Center, Rochester, NY.
authors: Bronislava
authors: B
authors: Polonsky
authors: Arrhythmia Institute, Valley Health System, Columbia University College of Physicians and Surgeons, New York, NY.
authors: Jonathan
authors: J
authors: Steinberg
authors: University of Rochester Medical Center, Rochester, NY.
authors: Arthur J
authors: AJ
authors: Moss
authors: University of Rochester Medical Center, Rochester, NY.
authors: Wojciech
authors: W
authors: Zareba
mesh_terms: D000368:Aged; D002304:Cardiac Pacing, Artificial; D058406:Cardiac Resynchronization Therapy; D009202:Cardiomyopathies / Q000628:therapy; D017147:Defibrillators, Implantable; D015716:Electrocardiography, Ambulatory; D005260:Female; D006333:Heart Failure / Q000628:therapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000628:therapy*; D018879:Ventricular Premature Complexes / Q000628:therapy*
keywords: biventricular pacing/defibrillation; clinical; electrocardiography; implantable devices; noninvasive techniques