ABSTRACT
Background: Peak oxygen uptake (VO 2) is often the focal point of cardiopulmonary exercise testing among patients with heart failure (HF). Breath-by-breath VO 2 kinetic patterns at exercise onset, during low-level and submaximal exercise, and during recovery may provide incremental insight into HF severity and etiologies of exercise limitation. Objective: The aim of this systematic review was to explore VO 2 recovery delay (VO 2 RD) across the spectrum of left ventricular function. Methods: A systematic review was conducted using several online databases (EMBASE, Cumulative Index to Nursing and Allied Health Literature, PubMed and Web of Science). Steps outlined by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses were followed. Search terms included VO 2 RD OR VO 2 off kinetics AND HF, peak VO 2 AND recovery. All articles were uploaded to Covidence. Results: Four studies met the inclusion criteria. The definition of VO 2 RD varied across studies. Recovery delay was consistently observed in HF patients compared to controls indicating VO 2 RD discriminates between those with and without HF. Control groups showed VO 2 decline almost immediately after exercise. VO 2 RD had a significant positive linear relationship to N-terminal prohormone of brain natriuretic and Doppler echo E/e' while demonstrating an inverse relationship with peak cardiac output and survival duration. Conclusions: VO 2 RD, unlike peak VO 2, is relatively cardiospecific. Oxygen recovery kinetics offer insight into disease severity and discrimination of healthy participants from those with HF. © 2023 Heart and Mind ;Published by Wolters Kluwer - Medknow.