title: Reproducibility for Heart Rate Variability Analysis during 6-Min Walk Test in Patients with Heart Failure and Agreement between Devices.
abstract: Heart rate variability (HRV) analysis is a useful method to assess abnormal functioning in the autonomic nervous system and to predict cardiac events in patients with heart failure (HF). HRV measurements with heart rate monitors have been validated with an electrocardiograph in healthy subjects but not in patients with HF. We explored the reproducibility of HRV in two consecutive six-minute walk tests (6MW), 60-minute apart, using a heart rate monitor (PolarS810i) and a portable electrocardiograph (called Holter) in 50 HF patients (mean age 59 years, NYHA II, left ventricular ejection fraction ~35%). The reproducibility for each device was analysed using a paired t-test or the Wilcoxon signed-rank test. Additionally, we assessed the agreement between the two devices based on the HRV indices at rest, during the 6MW and during recovery using concordance correlation coefficients (CCC), 95% confidence intervals and Bland-Altman plots. The test-retest for the HRV analyses was reproducible using Holter and PolarS810i at rest but not during recovery. In the second 6MW, patients showed significant increases in rMSSD and walking distance. The PolarS810i measurements had remarkably high concordance correlation [0.86<CCC<0.99] based on Holter at rest, during 6MW and recovery. At higher rates, a small effect in increasing differences between Holter and Polar in R-R intervals was observed. In conclusion, our study showed good reproducibility of HRV at rest in two consecutive 6MW using Holter and PolarS810i. Additionally, PolarS810i produced good agreements in short-term HRV indices based on Holter simultaneous recordings at rest, during the 6MW and recovery in HF patients.
authors.affiliation: Department of Physiotherapy, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Lays Magalhães
authors.initials: LM
authors.lastname: Braga
authors.affiliation: Pulmonary Division of Heart Institute (InCor) do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Gustavo Faibischew
authors.initials: GF
authors.lastname: Prado
authors.affiliation: Dante Pazzanese Institute of Cardiology São Paulo State, São Paulo, Brazil.
authors.forename: Iracema Ioco Kikuchi
authors.initials: II
authors.lastname: Umeda
authors.affiliation: Department of Physiotherapy, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Tatiana Satie
authors.initials: TS
authors.lastname: Kawauchi
authors.affiliation: Dante Pazzanese Institute of Cardiology São Paulo State, São Paulo, Brazil.
authors.forename: Adriana Marques Fróes
authors.initials: AM
authors.lastname: Taboada
authors.affiliation: Department of Pathology, University of São Paulo Medical School, São Paulo, Brazil.
authors.forename: Raymundo Soares
authors.initials: RS
authors.lastname: Azevedo
authors.affiliation: Cardiology Division of Heart Institute (InCor) do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Horacio Gomes
authors.initials: HG
authors.lastname: Pereira Filho
authors.affiliation: Cardiology Division of Heart Institute (InCor) do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: César José
authors.initials: CJ
authors.lastname: Grupi
authors.affiliation: Dante Pazzanese Institute of Cardiology São Paulo State, São Paulo, Brazil.
authors.forename: Hayala Cristina Cavenague
authors.initials: HC
authors.lastname: Souza
authors.affiliation: Dante Pazzanese Institute of Cardiology São Paulo State, São Paulo, Brazil.
authors.forename: Dalmo Antônio Ribeiro
authors.initials: DA
authors.lastname: Moreira
authors.affiliation: Department of Physiotherapy, Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil.
authors.forename: Naomi Kondo
authors.identifier: http://orcid.org/0000-0001-7826-6798
authors.initials: NK
authors.lastname: Nakagawa
mesh_terms: D000368:Aged; D004562:Electrocardiography; D005260:Female; D006333:Heart Failure / Q000175:diagnosis* / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D000070857:Walk Test