Heart rate variability as a useful parameter in assessment of cardiac rehabilitation outcome

This chapter discusses heart rate variability (HRV) analysis as a tool to identify improvement in cardiac function following cardiac rehabilitation (CR). Two main themes are discussed. The use of the Borg Relative Perceived Exertion (RPE) scale and the 6-minute walk test (6MWT) are reviewed as tools for setting an appropriate level of exercise intensity and quantifying the effectiveness of CR, respectively. Cardiac functional changes using HRV are compared following CR and either coronary artery bypass grafting (CABG) or percutaneous coronary angioplasty intervention (PCI) when exercise intensity was based on the more traditional assessment for setting exercise intensity using maximal oxygen uptake (VO₂ max).