Background: Exercise performance improvement after training in heart failure (HF) can be due to central or peripheral changes. Methods and Results: In 70 HF stable patients we measured peak VO 2 and cardiac output (CO, inert gas rebreathing technique) and calculated arteriovenous O 2 differences (a-v O 2diff) before and after an 8-week training program. Peak VO 2 changed from 1111 ± 403 mL/minute to 1191 ± 441 (P 2diff from 17.5 ± 5.1 mL/100 mL to 16.6 ± 4.1 (P =.081). Changes in peak CO and a-v O 2diff allowed to identify 4 behaviors: group 1: (n = 15) reduction in peak CO and increase in a-v O 2diff (peak VO 2 unchanged, peak workload +9.5%); group 2: (n = 16) both peak CO and a-v O 2diff increased as well as peak VO 2 (23%) and workload (18%); group 3: (n = 4) peak CO and a-v O 2diff reduced as well as peak VO 2 (-18%) and workload (-5%); group 4: (n = 35) peak CO increased with a-v O 2diff reduced (increase in peak VO 2 by 5.5 and workload by 8.4%). Conclusions: Exercise training improves peakVO 2 by increasing CO with unchanged a-v O 2diff. A reduction after training of a-v O 2diff with an increase in CO is frequent (50% of cases), is suggestive of blood flow redistribution and, per se, not a sign of reduced muscle performance been associated with improved exercise capacity.
- cardiac output
- heart failure
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine