# Exercise training and high-sensitivity cardiac troponin-I in patients with heart failure with reduced ejection fraction PMID: 38268237 Journal: ESC Heart Failure Published: 2024-04-01 Authors: Riveland E, Valborgland T, Ushakova A, Skadberg Ø, Karlsen T, Hole T, Støylen A, Dalen H, Videm V, Koppen E, Linke A, Delagardelle C, Van Craenenbroeck EM, Beckers P, Prescott E, Halle M, Omland T, Ellingsen Ø, Larsen AI, SMARTEX‐HF Study Group ## Question Does a 12-week structured exercise training program reduce serum high-sensitivity cardiac troponin I in patients with stable symptomatic heart failure with reduced ejection fraction, and are troponin changes associated with left ventricular remodeling, VO2peak, and NT-proBNP? ## Summary This SMARTEX-HF substudy analyzed whether 12 weeks of exercise training changed high-sensitivity cardiac troponin I in people with stable heart failure with reduced ejection fraction. Patients were randomized to HIIT, moderate continuous training, or recommendation of regular exercise, but HIIT and moderate groups were combined because actual training intensities overlapped. Structured exercise modestly reduced troponin I within the intervention group, but the main comparison versus control was not statistically significant. In patients without selected additional comorbidities, structured exercise showed a significant between-group troponin I reduction. Exercise also improved VO2peak versus control. ## Population - 196 stable symptomatic HFrEF patients from SMARTEX-HF with hs-cTnI samples; NYHA II-III, median LVEF about 30%, mostly male and mostly ischemic heart failure. - Sample size: 196 - Age: Median 57 years in control and 61 years in structured exercise group. - Sex: 19% female overall; control 12/67 female and structured exercise 24/129 female. - Fitness level: Clinical HFrEF population; baseline VO2peak median 18.4 mL/kg/min in control and 16.8 mL/kg/min in structured exercise. - Health status: Stable heart failure with reduced ejection fraction, NYHA class II-III, on optimal tolerated guideline-recommended therapy available at the time. ## Methodology - Multicentre randomized SMARTEX-HF substudy using available hs-cTnI blood samples; HIIT and MCT arms were merged into a structured exercise training group because achieved intensities overlapped. - 12 weeks - International multicentre heart failure exercise-training trial with supervised treadmill or bicycle sessions for HIIT and MCT arms. - Randomized and controlled study design. ## Protocol - Structured exercise training (pooled HIIT and MCT). - Modality: Treadmill or bicycle. - Intensity: HIIT target 90-95% HRmax; MCT target 60-70% HRmax; groups pooled because actual intensities overlapped. - Session duration: HIIT approximately 38 minutes including warm-up and cool-down; MCT approximately 47 minutes. - Frequency: 3 supervised sessions per week. - Program length: 12 weeks. - Recommendation of regular exercise. - Modality: Regular exercise recommended; actual modality not reported in detail. - Intensity: Actual control exercise intensity not well characterized. - Program length: 12 weeks. ## Outcomes ### hs-cTnI in full population Status: mixed SET had a modest within-group hs-cTnI reduction, but the between-group comparison versus control was not statistically significant. SET median 11.9 to 11.5 ng/L, P = 0.030; SET versus control P = 0.116. Table delta SET -0.7 ng/L versus control -0.2 ng/L; relative-change comparison P = 0.184. ### hs-cTnI in patients without selected comorbidities Status: improved Among patients without atrial fibrillation, hypertension, diabetes mellitus, and COPD, SET showed a greater reduction in hs-cTnI than control. SET 10.9 to 9.2 ng/L, P = 0.002; control 6.4 to 5.8 ng/L, P = 0.64; delta SET -1.2 ng/L versus control -0.1 ng/L, P = 0.007. ### VO2peak Status: improved VO2peak improved in SET and differed from control at 12 weeks. Whole group 17.1 to 17.3 mL/kg/min, P = 0.003; SET 16.8 to 17.3 mL/kg/min, P < 0.0001; control did not change, P = 0.44; delta between SET and control P = 0.001. ### LVEDD Status: mixed LVEDD was associated with hs-cTnI levels; the model predicted lower hs-cTnI with lower LVEDD, but group delta results were not consistently significant. Each 1 mm LVEDD decrease associated with 1.2% lower hs-cTnI (95% CI 0.6% to 1.9%, P < 0.001). Table full-population delta SET -2.0 mm versus control 0.0 mm, P = 0.015. ### NT-proBNP Status: no clear change NT-proBNP did not change significantly and delta values did not differ between SET and control. Whole group P = 0.26; delta SET versus control P = 0.80. Model predicted 3.0% lower hs-cTnI for each 10% lower NT-proBNP, 95% CI 2.4% to 3.5%, P < 0.0001. ## Practical Insights - This article should be coded as structured clinical exercise evidence, not pure HIIT evidence, because HIIT and MCT arms were pooled. - Prescribed intensity and achieved intensity can diverge substantially in clinical interval training. - For HFrEF, exercise evidence is safety-sensitive and depends on stable disease, medical therapy, supervision, and clinical testing. - VO2peak improved with structured exercise, but biomarker improvements were modest and not significantly different versus control in the full population. ## Limitations - HIIT and MCT were pooled because actual training intensities overlapped. - Pooling limits concrete recommendations about which intensity level to use. - Control group physical activity and intensity data were limited. - Subgroup findings may be affected by baseline differences in NT-proBNP and hs-cTnI. - Potential influence of haemoconcentration on hs-cTnI changes. - Exact HIIT work-rest protocol was not reported in this article. - The study context predates contemporary HFrEF therapy with sacubitril-valsartan and SGLT2 inhibitors. ## Safety And Adherence - The public extraction did not identify a specific safety or adherence note. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/38268237/) (pubmed) - [DOI](https://doi.org/10.1002/ehf2.14674) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10966269/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.