title: Chronotropic incompetence and abnormal heart rate recovery early after left ventricular assist device implantation.
abstract: BACKGROUND
  Chronotropic response to exercise and heart rate recovery immediately after exercise (HRR(1) ) are valid prognostic markers in patients with chronic heart failure (CHF). The aim of this study was to evaluate heart rate profile during and after exercise in CHF patients early after left ventricular assist device (LVAD) implantation.
  
  
  METHODS
  We enrolled seven stable consecutive CHF patients (five males, mean age: 45 ± 16 years) after 1 month of LVAD (HeartMate II; Thoratec Corp, Pleasanton, CA, USA) implantation, seven healthy subjects, and 14 patients with advanced HF (HF control group) who performed an incremental symptom-limited cardiopulmonary exercise testing (CPET). CHF patients performed CPET at 1 and 3 months after LVAD. HRR(1) was defined as the HR difference from peak to 1 minute after exercise and chronotropic response to exercise as the chronotropic reserve ([CR, %]=[peak HR-resting HR/220-age-resting HR]× 100).
  
  
  RESULTS
  LVAD patients 3 months after implantation had a significantly different HR profile during exercise compared to healthy controls, with significantly lower CR (57 ± 31 vs 90 ± 14, %, P < 0.001) and HRR(1) (14 ± 6 vs 28 ± 8, bpm, P < 0.01). HR profile during exercise did not significantly change 1 and 3 months after LVAD implantation. There was no statistical difference compared to HF control group and LVAD group regarding cardiopulmonary parameters.
  
  
  CONCLUSIONS
  LVAD patients present an impaired CR and an abnormal HRR(1) after implantation, indicating significant cardiac autonomic abnormalities. These alterations seem to remain unaltered 3 months after LVAD implantation.
authors.affiliation: 1st Critical Care Medicine Department, Cardiopulmonary Exercise Testing and Rehabilitation Laboratory, National and Kapodestrian University of Athens, Athens, Greece. a-icu@med.uoa.gr
authors.forename: Stavros
authors.initials: S
authors.lastname: Dimopoulos
authors.forename: Nikolaos
authors.initials: N
authors.lastname: Diakos
authors.forename: Eleni
authors.initials: E
authors.lastname: Tseliou
authors.forename: Athanasios
authors.initials: A
authors.lastname: Tasoulis
authors.forename: Anthi
authors.initials: A
authors.lastname: Mpouchla
authors.forename: Christos
authors.initials: C
authors.lastname: Manetos
authors.forename: Lambros
authors.initials: L
authors.lastname: Katsaros
authors.forename: Stavros
authors.initials: S
authors.lastname: Drakos
authors.forename: John
authors.initials: J
authors.lastname: Terrovitis
authors.forename: Serafim
authors.initials: S
authors.lastname: Nanas
mesh_terms: D000328:Adult; D005080:Exercise Test; D005260:Female; D006333:Heart Failure / Q000628:therapy*; D006339:Heart Rate / Q000502:physiology*; D006352:Heart Ventricles / Q000503:physiopathology*; D006353:Heart-Assist Devices; D006801:Humans; D008297:Male; D008875:Middle Aged; D019919:Prosthesis Implantation; D016896:Treatment Outcome