Lvad pump speed increase is associated with increased peak exercise cardiac output and vo2, postponed anaerobic threshold and improved ventilatory efficiency

C. Vignati, A. Apostolo, G. Cattadori, S. Farina, A. Del Torto, S. Scuri, G. Gerosa, T. Bottio, V. Tarzia, J. Bejko, E. Sisillo, F. Nicoli, S. Sciomer, F. Alamanni, S. Paolillo, P. Agostoni

Research output: Contribution to journalArticle

Abstract

Backgrounds Peak exercise cardiac output (CO) increase is associated with an increase of peak oxygen uptake (VO2), provided that arteriovenous O2 difference [Δ(Ca − Cv)O2] does not decrease. At anaerobic threshold, VO2, is related to CO. We tested the hypothesis that, in heart failure (HF) patients with left ventricular assistance device (LVAD), an acute increase of CO obtained through changes in LVAD pump speed is associated with peak exercise and anaerobic threshold VO2 increase. Methods Fifteen of 20 patients bearing LVAD (Jarvik 2000) enrolled in the study successfully performed peak exercise evaluation. All patients had severe HF as shown by clinical evaluation, laboratory tests, echocardiography, spirometry with alveolar-capillary diffusion, and maximal cardiopulmonary exercise testing (CPET). CPETs with non-invasive CO measurements at rest and peak exercise were done on 2 days at LVAD pump speed set randomly at 2 and 4. Results Increasing LVAD pump speed from 2 to 4 increased CO from 3.4 ± 0.9 to 3.8 ± 1.0 L/min (ΔCO 0.4 ± 0.6 L/min, p = 0.04) and from 5.3 ± 1.3 to 5.9 ± 1.4 L/min (ΔCO 0.6 ± 0.7 L/min, p < 0.01) at rest and peak exercise, respectively. Similarly, VO2 increased from 788 ± 169 to 841 ± 152 mL/min (ΔVO2 52 ± 76 mL/min, p = 0.01) and from 568 ± 116 to 619 ± 124 mL/min (ΔVO2 69 ± 96 mL/min, p = 0.02) at peak exercise and at anaerobic threshold, respectively. Δ(Ca − Cv)O2 did not change significantly, while ventilatory efficiency improved (VE/VCO2 slope from 39.9 ± 5.4 to 34.9 ± 8.3, ΔVE/VCO2 − 5.0 ± 6.4, p < 0.01). Conclusions In HF, an increase in CO with a higher LVAD pump speed is associated with increased peak VO2, postponed anaerobic threshold, and improved ventilatory efficiency. © 2016 Elsevier Ireland Ltd
Original languageEnglish
Pages (from-to)28-32
Number of pages5
JournalInternational Journal of Cardiology
Volume230
DOIs
Publication statusPublished - 2017

Keywords

  • Cardiac output
  • Exercise testing
  • Heart failure
  • LVAD
  • adult
  • anaerobic threshold
  • Article
  • cardiopulmonary exercise test
  • clinical article
  • clinical evaluation
  • controlled study
  • disease severity
  • echocardiography
  • exercise
  • female
  • heart failure
  • heart output
  • human
  • laboratory test
  • left ventricular assist device
  • lung diffusion
  • male
  • oxygen consumption
  • spirometry
  • ventilatory efficiency
  • crossover procedure
  • double blind procedure
  • heart assist device
  • lung gas exchange
  • middle aged
  • pathophysiology
  • physiology
  • randomized controlled trial
  • Anaerobic Threshold
  • Cardiac Output
  • Cross-Over Studies
  • Double-Blind Method
  • Exercise
  • Female
  • Heart Failure
  • Heart-Assist Devices
  • Humans
  • Male
  • Middle Aged
  • Oxygen Consumption
  • Pulmonary Gas Exchange

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