Factors Associated With Improved Exercise Tolerance Among Patients Undergoing Long-Term Phase III Cardiac...

Area of Science:

• Cardiology
• Exercise Physiology
• Rehabilitation Medicine

Background:

• Long-term cardiac rehabilitation (CR) aims to improve exercise tolerance in cardiovascular disease patients.
• Identifying patient characteristics associated with sustained improvement is crucial for optimizing CR programs.

Purpose of the Study:

• To characterize individuals who achieve significant exercise tolerance improvements during extended outpatient CR.
• To analyze factors influencing peak oxygen uptake (VO2) changes over different phases of CR.

Main Methods:

• Prospective study of 124 cardiovascular disease patients in Phase II and III outpatient CR.
• Cardiopulmonary exercise testing at three timepoints: start of Phase II, end of Phase II, and 6 months post-Phase III.
• Modified Poisson regression and linear mixed-effects models to identify predictors of VO2 improvement and analyze changes over time.

Main Results:

• Responders (improved peak VO2) showed significantly lower peak VO2 at the end of Phase II compared to non-responders.
• Sustained improvement in peak VO2 and oxygen uptake efficiency (ΔVO2/ΔWR) from Phase II to 6-month follow-up predicted long-term gains.
• Responders had a significantly higher peak VO2 at the 6-month follow-up than non-responders.

Conclusions:

• Individuals demonstrating substantial peak VO2 gains in long-term CR had minimal improvement during the initial Phase II outpatient program.
• This highlights the importance of sustained physiological adaptations beyond the early stages of CR for long-term exercise capacity enhancement.