title: Effects of ivabradine on 6-minute walk test and quality of life in patients with previously implanted CRT-D.
abstract: BACKGROUND
  We aimed to evaluate clinical effects of additional heart rate control by ivabradine on life quality score and 6-minute walking test in patients with previously implanted biventricular cardiac resynchronization therapy defibrillator (CRT-D) with ischemic heart failure under regular treatment.
  
  
  METHODS
  Fifteen men and 14 women with a median age of 63 years (range, 48-79 years) were studied. Twenty-one patients were in New York Heart Association class II (8 patients were in class III), CRT-D implanted previously, and with resting heart rates greater than 70 beats per minute with sinus rhythm despite conventional medication. Patients were given 2.5- to 7.5-mg ivabradine orally twice a day, and drug dosage was titrated to decrease the patients' average heart rate to 70 beats per minute. Before and 3 months after ivabradine treatment, all patients underwent extensive clinical, echocardiographic, and laboratory evaluation.
  
  
  RESULTS
  Ivabradine treatment produced dose-dependent reductions in heart rate at rest and at peak exercise (91.9 ± 6.3 to 71.7 ± 4.8 and 114.4 ± 7.6 to 96.8 ± 4.8; P = 0.001 and P = 0.001, respectively). There were also significant improvements in life quality score (52.4 ± 9.5 to 37.9±7.8; P = 0.001) and 6-minute walking distance (278.7 ± 85.8 to 373.3 ± 94.0; P = 0.001) of patients. All patients with New York Heart Association class III became class II after 3 months of ivabradine treatment.
  
  
  CONCLUSIONS
  Heart rate reduction in a short-term period by ivabradine produced significant improvements in exercise capacity and life quality in patients with CRT-D and conventional therapy.
authors.affiliation: Department of Cardiology, Medical Park Hospital, Antalya, Turkey. drates07@gmail.com
authors.forename: Ismail
authors.initials: I
authors.lastname: Ates
authors.forename: Asuman H
authors.initials: AH
authors.lastname: Yavuz
authors.forename: Mehmet
authors.initials: M
authors.lastname: Doğru
authors.forename: Ahmet
authors.initials: A
authors.lastname: Genç
authors.forename: Şeref
authors.initials: Ş
authors.lastname: Ulucan
authors.forename: Metin
authors.initials: M
authors.lastname: Sarıkaya
authors.forename: Ramazan
authors.initials: R
authors.lastname: Cetinkaya
authors.forename: Ahmet
authors.initials: A
authors.lastname: Keser
authors.forename: Mahmut
authors.initials: M
authors.lastname: Akpek
authors.forename: Mehmet G
authors.initials: MG
authors.lastname: Kaya
mesh_terms: D000368:Aged; D001552:Benzazepines / Q000627:therapeutic use*; D058406:Cardiac Resynchronization Therapy; D017147:Defibrillators, Implantable; D005080:Exercise Test / Q000379:methods; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000503:physiopathology / Q000601:surgery / Q000628:therapy*; D006801:Humans; D000077550:Ivabradine; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011788:Quality of Life; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D001552:Benzazepines; D000077550:Ivabradine