title: The effect of lung volume reduction surgery on chronotropic incompetence.
abstract: BACKGROUND
  Chronotropic incompetence (CI) is a marker of poor prognosis in patients with COPD. Treatments that improve pulmonary function and exercise capacity may affect CI. Objectives are to evaluate CI before and after lung volume reduction surgery (LVRS) and determine if changes in CI are associated with changes in pulmonary function and exercise capacity.
  
  
  METHODS
  We performed a retrospective review of 75 patients who underwent LVRS and who had complete cardiopulmonary exercise testing and concurrent pulmonary function tests two months before and about 6 months after surgery. Additionally we evaluated 28 control patients that were randomized to medical treatment as part of the National Emphysema Treatment Trial at our center. We studied CI using the percent of predicted heart rate reserve=(heart rate peak-heart rate rest)/((208-0.7×age)-heart rate rest)×100, before and after surgery and compared it to the control group.
  
  
  RESULTS
  Mean percent of predicted heart rate reserve improved from 41% to 50% (p-value <0.001) after LVRS, while the control group did not change. The mean forced vital capacity and expiratory volume in 1s, peak oxygen consumption, carbon dioxide production, ventilation, tidal volume and maximal workload all improved in the surgery group, while the controls did not improve.
  
  
  CONCLUSIONS
  CI improves after LVRS in a population of patients with COPD. CI improvements are associated with the increases in pulmonary function and exercise capacity. This improvement is seen in a domain of known cardiopulmonary impairment prior to surgery that improves as a positive response to the therapy of LVRS.
authors: Department of Rehabilitation and Regenerative Medicine, Columbia University Medical Center, NY, NY 10032, USA. hfa2104@columbia.edu
authors: Hilary F
authors: HF
authors: Armstrong
authors: Jose
authors: J
authors: Gonzalez-Costello
authors: Ulrich P
authors: UP
authors: Jorde
authors: Mark E
authors: ME
authors: Ginsburg
authors: Aimee M
authors: AM
authors: Layton
authors: Byron M
authors: BM
authors: Thomashow
authors: Matthew N
authors: MN
authors: Bartels
mesh_terms: D001145:Arrhythmias, Cardiac / Q000503:physiopathology / Q000601:surgery*; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011013:Pneumonectomy; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000503:physiopathology / Q000601:surgery*; D012129:Respiratory Function Tests; D012189:Retrospective Studies