title: Prospective randomized trial of moderately strenuous aerobic exercise after an implantable cardioverter defibrillator.
abstract: BACKGROUND
  Despite its salutary effects on health, aerobic exercise is often avoided after receipt of an implantable cardioverter defibrillator (ICD) because of fears that exercise may provoke acute arrhythmias. We prospectively evaluated the effects of a home aerobic exercise training and maintenance program (EX) on aerobic performance, ICD shocks, and hospitalizations exclusively in ICD recipients.
  
  
  RESULTS
  A total of 160 patients (124 men and 36 women) were randomly assigned who had an ICD for primary (43%) or secondary (57%) prevention to EX or usual care (UC). The primary outcome was peak oxygen consumption, measured with cardiopulmonary exercise testing at baseline and 8 and 24 weeks. EX consisted of 8 weeks of home walking for 1 h/d, 5 d/wk at 60% to 80% of heart rate reserve, followed by 16 weeks of maintenance home walking for 150 min/wk. Adherence to EX was determined from exercise logs, ambulatory heart rate recordings of exercise, and weekly telephone contacts. Patients assigned to UC received no exercise directives and were monitored by monthly telephone contact. Adverse events were identified by ICD interrogations, patient reports, and medical charts. ICD recipients averaged 55±12 years and mean ejection fraction of 40.6±15.7; all were taking β-blocker medications. EX significantly increased peak oxygen consumption (EX, 26.7±7.0 mL/kg per minute; UC, 23.9±6.6 mL/kg per minute; P=0.002) at 8 weeks, which persisted during maintenance exercise at 24 weeks (EX, 26.9±7.7 mL/kg per minute; UC, 23.4±6.0 mL/kg per minute; P<0.001). ICD shocks were infrequent (EX=4 versus UC=8), with no differences in hospitalizations or deaths between groups.
  
  
  CONCLUSIONS
  Prescribed home exercise is safe and significantly improves cardiovascular performance in ICD recipients without causing shocks or hospitalizations.
  
  
  BACKGROUND
  URL: http://www.clinicaltrials.gov. Unique identifier: NCT00522340.
authors: From Biobehavioral Nursing and Health Systems (C.M.D., R.L.B.), Division of Cardiology, Arrhythmia Services, Department of Medicine (C.M.D., P.J.K.), Division of Pulmonary and Critical Care, Departments of Medicine and Physiology and Biophysics (R.W.G.), University of Washington Seattle; and Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (G.L.F.). cindyd@uw.edu.
authors: Cynthia M
authors: CM
authors: Dougherty
authors: From Biobehavioral Nursing and Health Systems (C.M.D., R.L.B.), Division of Cardiology, Arrhythmia Services, Department of Medicine (C.M.D., P.J.K.), Division of Pulmonary and Critical Care, Departments of Medicine and Physiology and Biophysics (R.W.G.), University of Washington Seattle; and Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (G.L.F.).
authors: Robb W
authors: RW
authors: Glenny
authors: From Biobehavioral Nursing and Health Systems (C.M.D., R.L.B.), Division of Cardiology, Arrhythmia Services, Department of Medicine (C.M.D., P.J.K.), Division of Pulmonary and Critical Care, Departments of Medicine and Physiology and Biophysics (R.W.G.), University of Washington Seattle; and Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (G.L.F.).
authors: Robert L
authors: RL
authors: Burr
authors: From Biobehavioral Nursing and Health Systems (C.M.D., R.L.B.), Division of Cardiology, Arrhythmia Services, Department of Medicine (C.M.D., P.J.K.), Division of Pulmonary and Critical Care, Departments of Medicine and Physiology and Biophysics (R.W.G.), University of Washington Seattle; and Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (G.L.F.).
authors: Gayle L
authors: GL
authors: Flo
authors: From Biobehavioral Nursing and Health Systems (C.M.D., R.L.B.), Division of Cardiology, Arrhythmia Services, Department of Medicine (C.M.D., P.J.K.), Division of Pulmonary and Critical Care, Departments of Medicine and Physiology and Biophysics (R.W.G.), University of Washington Seattle; and Division of Cardiovascular Diseases, Mayo Clinic, Rochester, MN (G.L.F.).
authors: Peter J
authors: PJ
authors: Kudenchuk
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D000328:Adult; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000209:etiology* / Q000517:prevention & control; D002311:Cardiomyopathy, Dilated / Q000534:rehabilitation / Q000628:therapy; D017147:Defibrillators, Implantable; D004554:Electric Countershock; D015444:Exercise; D005081:Exercise Therapy / Q000009:adverse effects*; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000534:rehabilitation / Q000628:therapy; D010101:Oxygen Consumption; D010349:Patient Compliance; D011446:Prospective Studies; D012648:Self Care; D016896:Treatment Outcome; D016138:Walking
chemical_list: D000319:Adrenergic beta-Antagonists
keywords: arrhythmias, cardiac; defibrillators, implantable; exercise; heart arrest; heart rate