title: Relation between VE/VCO2 slope and maximum phonation time in chronic heart failure patients.
abstract: This study aimed to determine the relation between the regression slope relating minute ventilation to carbon dioxide output (VE/VCO2 slope) and maximum phonation time (MPT), and the MPT required to attain a threshold value for VE/VCO2 slope of ≤ 34 in chronic heart failure (CHF) patients. This cross-sectional study enrolled 115 CHF patients (mean age, 54.5 years; men, 84.9%). VE/VCO2 slope was assessed during cardiopulmonary exercise testing (CPX). Thereafter, patients were divided into 2 groups according to exercise capacity: VE/VCO2 slope ≤ 34 (VE/VCO2 ≤ 34 group, n = 81) and VE/VCO2 slope > 34 (VE/VCO2 > 34 group, n = 34). For MPT measurements, all patients produced a sustained vowel/a:/ for as long as possible during respiratory effort from the seated position. All subjects showed significant negative correlation between VE/VCO2 slope and MPT (r = -0.51, P < 0.001). After adjustment for clinical characteristics, MPT was significantly higher in the VE/VCO2 ≤ 34 group vs VE/VCO2 > 34 group (21.4 ± 6.4 vs 17.4 ± 4.3 s, F = 7.4, P = 0.007). The appropriate MPT cut-off value for identifying a VE/VCO2 slope ≤ 34 was 18.12 seconds. An MPT value of 18.12 seconds may be a useful target value for identifying CHF patients with a VE/VCO2 slope ≤ 34 and for risk management in these patients.
authors.affiliation: From the Graduate School of Health Sciences, Kobe University, Kobe, Japan (KPI); Department of Rehabilitation Medicine, St. Marianna University School of Medicine Hospital, Kawasaki, Japan (SW, ST, SM, TS); Department of Health and Exercise Science, Wake Forest University, Winston-Salem, NC, USA (PHB); Department of Physical Therapy, Tokushima Bunri University, Tokushima, Japan (YH); Faculty of Sport Sciences, Waseda University, Tokorozawa, Japan (KO); Department of Rehabilitation, Visiting Nursing and Rehabilitation Network, Kawasaki, Japan (TS, YO); Division of Cardiology, Department of Internal Medicine, St. Marianna University School of Medicine, Kawasaki, Japan (KS, YJA); Division of Cardiology, St. Marianna University Toyoko Hospital, Kawasaki, Japan (NO); Division of Cardiology, St. Marianna University Yokohama-City Seibu Hospital, Yokohama, Japan (KO); and Department of Orthopedic Surgery, St. Marianna University School of Medicine, Kawasaki, Japan (HS).
authors.forename: Kazuhiro P
authors.initials: KP
authors.lastname: Izawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Watanabe
authors.forename: Peter H
authors.initials: PH
authors.lastname: Brubaker
authors.forename: Shinobu
authors.initials: S
authors.lastname: Tochimoto
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Hirano
authors.forename: Shinya
authors.initials: S
authors.lastname: Matsushima
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Suzuki
authors.forename: Koichiro
authors.initials: K
authors.lastname: Oka
authors.forename: Takashi
authors.initials: T
authors.lastname: Saito
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Omori
authors.forename: Kengo
authors.initials: K
authors.lastname: Suzuki
authors.forename: Naohiko
authors.initials: N
authors.lastname: Osada
authors.forename: Kazuto
authors.initials: K
authors.lastname: Omiya
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Shimizu
authors.forename: Yoshihiro J
authors.initials: YJ
authors.lastname: Akashi
mesh_terms: D003430:Cross-Sectional Studies; D017079:Exercise Tolerance / Q000502:physiology; D005260:Female; D006333:Heart Failure / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010699:Phonation / Q000502:physiology*; D011659:Pulmonary Gas Exchange / Q000502:physiology*; D012123:Pulmonary Ventilation / Q000502:physiology*