Permanent Pacemaker Response and The Role of Exercise Modality on Maximum Oxygen Consumption During CardioPulmonary Exercise Testing for Heart Transplant Assessment

Trial to be conducted at The Prince Charles Hospital, Brisbane QLD. This trial will involve patients with established severe heart failure who are already undergoing annual cardiopulmonary exercise testing as part of their functional assessment. These tests are traditionally performed on a stationary bike. A subset of these patients have permanent pacemakers implanted as part of their heart failure. We hypothesise that these pacemakers do not increment heart rate appropriately when patients are using a stationary bike, therefore giving an inappropriately how maximal anaerobic threshold when assessed with a cardiopulmonary exercise test on a stationary bike. We aim to recruit 6 patients with heart failure and pacemakers who already undergo a stationary bike cardiopulmonary exercise test and have them undergo a second cardiopulmonary exercise test on a treadmill (intervention group). We will have a second group of 6 patients as a control group - these will be patients with a similar degree of heart failure but who do not have pacemakers. We hypothesise that pacemaker dependant heart failure patients will have better cardiac function indices when they do cardiopulmonary exercise tests on a treadmill as opposed to a stationary bike. The principal investigator is Dr Benjamin Gerhardy, a thoracic medicine advanced trainee currently working at The Prince Charles Hospital. Co-investigators including thoracic physicians, a cardiologist and a respiratory scientist. The tests will be administered/supervised by the principal investigator, with support from a respiratory scientist to ensure appropriate set-up of the equipment and for patient safety. There will be a time period of no more than 30 days between the initial (stationary bike) cardiopulmonary exercise test and the treadmill cardiopulmonary exercise test, with a minimum time period between the two tests of 7 days. The protocol will be a fixed incremental protocol, with workload increasing by 16 watts every 2 minutes until exhaustion. Spirometry on a calibrated spirometer will be performed prior to commencing the cardiopulmonary exercise test. Throughout the test a variety of parameters will be measured or derived including: Cardiac: heart rate (and heart rate reserve), blood pressure, cardiac rhythm Respiratory: respiratory frequency, tidal volume, minute ventilation, ventilatory reserve, peripheral oxygen saturation, oxygen pulse, Ve/VCO2, Ve/VO2 Metabolic: VO2 max, anaerobic threshold, work rate, respiratory exchange ratio