Exercise following heart transplantation

During the past 2 decades, heart transplantation has evolved from an experi mental mental procedure to an accepted life-extending therapy for patients with endstage heart failure. However, with dramatic improvements in organ p reservation, surgery and immunosuppressive drug management, short term surv ival is no longer the pivotal issue for most heart transplant recipients (H TR), Rather, a return to functional lifestyle with good quality of life is now the desired procedural outcome. To achieve this outcome, aggressive exe rcise rehabilitation is essential. HTR present unique exercise challenges. Preoperatively, most of these patie nts had chronic debilitating cardiac illness. Many HTR have had prolonged p retransplantation hospitalisation for inotropic support or a ventricular as sist device. Decrements in peak oxygen consumption (VO2peak and related car diovascular parameters regress approximately 26% within the first 1 to 3 we eks of sustained bed rest. Consequently, extremely poor aerobic capacity an d cardiac cachexia are not unusual occurrences in HTR who have required mec hanical support or been confined to bed rest. Moreover, HTR must also conte nd with de nose exercise challenges conferred by chronic cardiac denervatio n and the multiple sequelae resulting from immunosuppression therapy. There is ample evidence that both endurance and resistance training are wel l tolerated in HTR. Moreover, there is growing clinical consensus that spec ific endurance and resistance training regimens in HTR can be efficacious a djunctive therapies in the prevention of immunosuppression-induced adverse effects and the reversal of pathophysiological consequences associated with cardiac denervation and antecedent heart failure. For example, some HTR wh o remain compliant during strenuous long term endurance training programmes achieve peak heart rate and VO2peak values late after transplantation that approach age-matched norms up to approximately 95% of predicted). These be nefits are not seen in HTR who do not participate in structured endurance e xercise training. Rather, peak heart rate and VO2peak values in untrained H TR remain approximately 60 to 70% of predicted indefinitely. However, the m echanisms responsible for improved peak heart rate, VO2peak and total exerc ise time are not completely understood and require further investigation. R ecent studies have also demonstrated that resistance exercise training may be an effective countermeasure for corticosteroid- induced osteoporosis and skeletal muscle myopathy. HTR who participate in specific resistance train ing programmes successfully restore bone mineral density (BMD) in both the axial and appendicular skeleton to pretransplantation levels, increase lean mass to levels greater than pretransplantation, and reduce body fat. In co ntrast, HTR who do not participate in resistance training lose approximatel y 15% BMD from the lumbar spine early in the postoperative period and exper ience further gradual reductions in BMD and muscle mass late after transpla ntation.