# Feasibility of high-intensity interval training in patients with left ventricular assist devices: a pilot study PMID: 33205573 Journal: ESC Heart Failure Published: 2020-11-17 Authors: Alvarez Villela M, Chinnadurai T, Salkey K, Furlani A, Yanamandala M, Vukelic S, Sims DB, Shin JJ, Saeed O, Jorde UP, Patel SR ## Question Can stable patients on chronic LVAD support complete a short CPX-guided HIIT program without major adverse events, and what are the observed effects on aerobic capacity and left ventricular remodelling? ## Summary This uncontrolled pilot study tested whether stable patients with durable left ventricular assist devices could complete a short, personalized, physician-supervised HIIT program. Fifteen patients began training and twelve completed post-training testing. The protocol was feasible for selected stable LVAD patients, with no major adverse events, high prescribed workload completion, improved oxygen uptake at ventilatory threshold, but no improvement in VO2peak or quality-of-life scores. ## Population - 15 stable adults with durable LVAD support enrolled in a single-arm HIIT pilot study. - Sample size: 15 - Age: Median 51 years, range 29-71. - Sex: 10 men, 66% male. - Fitness level: Low baseline aerobic capacity; VO2peak 11.9 (9.5, 14.8) mL/kg/min. - Health status: Advanced heart failure patients on durable LVAD support, clinically stable and at least 3 months after implantation. ## Methodology - Prospective single-arm pilot feasibility study. - 5 weeks of HIIT plus pre/post testing. - Montefiore Medical Center; physician-supervised cycle ergometer training and clinical testing. ## Protocol - CPX-guided LVAD HIIT. - Modality: Upright cycle ergometer. - Work intervals: 30 s high-intensity interval. - Recovery: 4 min active recovery. - Sets or repetitions: Six intervals. - Intensity: Sessions 1-3: 80% baseline PPO intervals; session 4 onward: 100% PPO intervals if tolerated. Warm-up and recovery also prescribed as percentages of PPO. - Session duration: 30 min. - Frequency: 3 sessions/week. - Program length: 5 weeks. - Progression: Induction phase for first three sessions, then increased workloads from session 4; reduction back to induction workloads allowed if not tolerated. ## Outcomes ### Feasibility/workload completion Status: improved Participants completed a median 90% of total prescribed workload and a median of 13 sessions. 90% (IQR 78%, 99%); median sessions 13, range 6-15. ### Safety Status: improved No major adverse events occurred during 204 supervised sessions; one minor asymptomatic supraventricular tachycardia event was managed by lower workloads. Descriptive safety outcome; no inferential P value. ### VO2 at ventilatory threshold Status: improved Submaximal oxygen uptake improved after HIIT. 7.1 (6.5, 9.1) to 8.5 (7.7, 9.3) mL/kg/min; P = 0.04. ### Work rate at ventilatory threshold Status: improved Submaximal work rate improved after HIIT. 44 (14, 54) to 55 (21, 66) W; P = 0.054. ### VO2peak Status: no clear change Peak oxygen uptake did not improve. 11.9 (9.5, 14.8) to 12.0 (10.0, 15.0) mL/kg/min; P = 0.6. ### Left ventricular end-diastolic volume Status: improved LV end-diastolic volume decreased in the paired turndown echocardiogram subset. 168 (144, 216) to 159 (124, 212) mL; n = 7 in text, table labelled N = 8; P = 0.02. ### KCCQ quality of life Status: no clear change KCCQ overall summary and physical limitation scores did not significantly improve. Overall summary 72 (60, 79) to 64 (53, 84), P = 0.5; physical limitation 75 (62, 88) to 75 (62, 92), P = 0.51. ## Practical Insights - In selected stable LVAD patients, very short work intervals with long active recoveries can be feasible under physician supervision. - CPX-derived workload may be preferable to heart-rate prescription when chronotropic incompetence and impaired heart-rate recovery are common. - Clinical HIIT protocols need built-in regression rules for intolerance or arrhythmia signals. - Improved submaximal capacity may matter even when VO2peak and short-term quality-of-life scores do not change. ## Limitations - No control group. - Small pilot sample. - Only selected stable LVAD patients were enrolled; 25% of screened patients entered the study. - No progressive workload increases after session 4. - Short 5-week intervention. - Some patients trained at RPE below 13. - White patients were under-represented. - Not directly translatable to unsupervised or non-clinical exercise settings. ## Safety And Adherence - No major adverse events occurred during 204 supervised sessions. - No sessions were discontinued by the supervising physician. - One participant had recurrent asymptomatic supraventricular tachycardia after the session 4 workload increase and completed all sessions using lower induction workloads. - Two participants withdrew early because of training intolerance. - One participant was urgently listed for transplant because of LVAD malfunction. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/33205573/) (pubmed) - [DOI](https://doi.org/10.1002/ehf2.13106) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7835573/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.