title: Is applying the same exercise-based inpatient program to normal and reduced left ventricular function patients the best strategy after coronary surgery? A focus on autonomic cardiac response.
abstract: OBJECTIVE
  To assess whether the same exercise-based inpatient program applied to patients with normal and reduced left ventricular function (LVF) evokes a similar cardiac autonomic response after coronary artery bypass graft (CABG).
  
  
  METHODS
  Forty-four patients post-CABG, subgrouped according to normal LVF [LVFN: n = 23; left ventricular ejection fraction (LVEF) ≥ 55%] and reduced LVF (LVFR: n = 21; LVEF 35-54%), were included. All initiated the exercise protocol on post-operative day 1 (PO1), following a whole progressive program until discharge. Cardiac autonomic response was assessed by the indices of heart rate variability (HRV) at rest and during exercise (extremity range of motion and ambulation).
  
  
  RESULTS
  During ambulation, lower values of HRV indices were found in the LVFR group compared with the LVFN group [standard deviation of all RR (STDRR; 6.1 ± 2.7 versus 8.9 ± 4.7 ms), baseline width of the RR histogram (TINN; 30.6 ± 14.8 versus 45.8 ± 24.9 ms), SD2 (14.8 ± 8.0 versus 21.3 ± 9.0 ms), Shannon entropy (3.6 ± 0.5 versus 3.9 ± 0.4) and correlation dimension (0.08 ± 0.2 versus 0.2 ± 0.2)]. Also, when comparing the ambulation to rest change, lower values were observed in the LVFR group for linear (STDRR, TINN, RR TRI, rMSSD) and non-linear (SD2 and correlation dimension) HRV indices (p < 0.05). On PO1, we observed only intra-group differences between rest and exercise (extremity range of motion), for mean intervals between heart beats and heart rate.
  
  
  CONCLUSIONS
  For patients with LVFN, the same inpatient exercise protocol triggered a more attenuated autonomic response compared with patients with LVFR. These findings have implications as to how exercise should be prescribed according to LVF in the early stages following recovery from CABG. Implications for Rehabilitation Exercise-based inpatient program, performed by post-CABG patients who have normal left ventricular function, triggered a more attenuated cardiac autonomic response compared with patients with reduced left ventricular function. Volume of the inpatient exercises should be prescribed according to the left ventricular function in the early stages following recovery from CABG.
authors: Cardiopulmonary Physiotherapy Laboratory, Nucleus of Research in Physical Exercise, Federal University of Sao Carlos , Sao Paulo , Brazil .
authors: Renata Gonçalves
authors: RG
authors: Mendes
authors: Rodrigo Polaquini
authors: RP
authors: Simões
authors: Fernando de Souza Melo
authors: Fde S
authors: Costa
authors: Camila Bianca Falasco
authors: CB
authors: Pantoni
authors: Luciana
authors: L
authors: Di Thommazo-Luporini
authors: Sérgio
authors: S
authors: Luzzi
authors: Othon
authors: O
authors: Amaral-Neto
authors: Ross
authors: R
authors: Arena
authors: Aparecida Maria
authors: AM
authors: Catai
authors: Audrey
authors: A
authors: Borghi-Silva
mesh_terms: D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001026:Coronary Artery Bypass / Q000379:methods / Q000534:rehabilitation*; D003327:Coronary Disease / Q000150:complications / Q000503:physiopathology / Q000601:surgery; D005081:Exercise Therapy / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D017144:Focus Groups; D006339:Heart Rate; D006801:Humans; D007297:Inpatients; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods*; D013318:Stroke Volume; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology / Q000534:rehabilitation; D016277:Ventricular Function, Left