Dtaset related to the article The double anaerobic threshold in heart failure: MECKI score database overview. ESC Heart Fail. 2022;9:2119-2124.

<p>&nbsp;</p> <p><strong>Aims:&nbsp;</strong>In heart failure (HF), anaerobic threshold (AT) may be indeterminable but its value held a relevant prognostic role. AT is evaluated joining three methods: V-slope, ventilatory equivalent, and end-tidal methods. The possible non-concordance between the V-slope (met AT) and the other two methods (vent AT) has been highlighted in healthy individuals and named double threshold (DT).</p> <p><strong>Methods and results:&nbsp;</strong>We reanalysed 1075 cardiopulmonary exercise tests of HF patients recruited in the Metabolic Exercise test data combined with Cardiac and Kidney Indexes (MECKI) score database. We identified DT in 43% of cases. Met AT precedes vent AT being met-vent&Delta;VO₂&nbsp;221 (interquartile range: 129-319) mL/min. Peak VO₂&nbsp;, 1307 &plusmn; 485 vs. 1343 &plusmn; 446 mL/min (63 &plusmn; 17 vs. 63 &plusmn; 17 percentage of predicted), was similar between DT+ and DT- patients. Differently, DT+ showed a lower ventilatory vs. carbon dioxide production (VE/VCO₂&nbsp;) slope (29.6 &plusmn; 6.1 vs. 31.0 &plusmn; 6.3), a lower peak exercise end-tidal oxygen tension (PetO₂&nbsp;) 115.3 (111.5-118.9) vs. 116.4 (112.4-120.2) mmHg, and a higher carbon dioxide tension (PetCO₂&nbsp;) 34.2 (30.9-37.1) vs. 32.4 (28.7-35.5) mmHg. Vent AT showed a significant higher VO₂&nbsp;, 957 &plusmn; 318 vs. 719 &plusmn; 252 mL/min, VCO₂&nbsp;, 939 &plusmn; 319 vs. 627 &plusmn; 226 mL/min, ventilation, 31.0 &plusmn; 8.3 vs. 22.5 &plusmn; 6.3 L/min, respiratory exchange ratio, 0.98 &plusmn; 0.08 vs. 0.87 &plusmn; 0.07, PetO₂&nbsp;, 108 (104-112) vs. 105 (101-109) mmHg, PetCO₂&nbsp;, 37 (34-40) vs. 36 (33-39) mmHg, and VE/VO₂&nbsp;ratio, 33.5 &plusmn; 6.7 vs. 32.6 &plusmn; 6.9, but lower VE/VCO₂&nbsp;ratio, 33 (30-37) vs. 36 (32-41), compared with met AT. At 2 year survival by Kaplan-Meier analysis, even adjusted for confounders, DT resulted not associated with survival.</p> <p><strong>Conclusions:&nbsp;</strong>Double threshold is frequently observed in HF patients. DT+ is associated to a decreased ventilatory response during exercise.</p> <p>&nbsp;</p>