Left-ventricular function and autonomic cardiac responses after short-term inpatient cardiac rehabilitation: A prospective clinical trial

Patients awaiting first-time CABG were invited to participate in the study, and enrolled after giving written informed consent. Participants were divided into left ventricular function (LVF) normal group (LVFN group) or left ventricular function (LVF) reduced group (LVFR group). Pre-operatively, the patient’s age, gender, weight, height, body mass index, risk factors, pharmacological treatment and other relevant medical history were documented. Additionally, a pulmonary function test was performed to investigate the presence of chronic obstructive pulmonary disease (COPD) and education about the effects of surgery on cardiorespiratory function, post-operative routines and cardiac rehabilitation programme were provided. Post-operatively, surgical and hospital data were recorded and all patients were engaged in cardiac rehabilitation supervised by one of three members of physiotherapy staff, specifically trained. All patients participated in a once-daily individual short-term supervised inpatient physiotherapy exercise protocol consisted of early mobilization plus respiratory exercises with approximate duration of daily physiotherapy sessions of 60 minutes per day starting on the first postoperative day until discharge Briefly, this protocol consisted of progressive exercises, range of movement (ROM) active-assistive movements to climbing flights of stairs. Estimated energy expenditure during this program was initially set at approximately 2 metabolic equivalent (MET)s and progressed to 4 METs. Exercise intensity was gauged by heart rate with an upper threshold set at standing resting heart rate +20bpm, monitored by a Polar S810i telemetry system. Moreover, the patients performed voluntary deep-breathing exercises from functional residual capacity to total lung capacity (40 deep breaths in four sets of 10, each breath included a 5 second hold at end inspiration) followed by coughs or huffs (with wound support) supervised once daily. Patients were instructed to perform these breathing and coughing exercises independently every waking hour. The outcome measures of heart rate (HR) and R-R intervals (R-Ri) were collected prior (pre-operative and first post-operative day - PO1) and after (day before discharge) to cardiac rehabilitation.