EVALUATION OF FUNCTIONAL CAPACITY, VARIABILITY AND ON AND OFF KINETICS OF HEART RATE DURING THE SIX-MINUTE WALK TEST IN PATIENTS WITH COPD

• Grant number: 23/03834-1
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: June 01, 2023
• End date: May 31, 2024
• Field of knowledge: Health Sciences - Physiotherapy and Occupational Therapy
• Principal Investigator: Audrey Borghi Silva
• Grantee: Letícia Roberta Lourencetti
• Host Institution: Centro de Ciências Biológicas e da Saúde (CCBS). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 15/26501-1 - Study of limiting factors to physical exercise and adjunct effects to rehabilitation on cardiorespiratory disease: a multicentre approach, AP.TEM

Abstract

Introduction: The six-minute walk test (6MWT) is widely disseminated and used in clinical practice to assess functional performance in patients with Chronic Obstructive Pulmonary Disease (COPD). However, little has been studied about the behavior of cardiovascular autonomic control, from heart rate variability (HRV) and kinetics (on and off) of heart rate (HR) during the evaluation of a submaximal test.Objectives: To evaluate the functional capacity by distance covered, HRV and HR kinetics (on and off) during the 6MWT in patients with COPD.Materials and Methods: In the first stage, volunteers from 50 years of age will undergo a clinical evaluation, pulmonary function tests and echocardiography, for diagnostic confirmation, stratification of disease severity, and exclusion of concomitant Heart Failure (HF). In the second stage, they will perform the 6MWT and, during the test, the individuals will be constantly monitored by a heart rate monitor to collect the R-R intervals. During the test, the following control variables will be evaluated: systolic and diastolic blood pressure (SBP, DBP), peripheral oxygen saturation (SpO2) and subjective perception of exertion for dyspnea and fatigue. At the end, the distance covered in meters will be measured, as well as the % of the predicted. The R-R intervals will be transferred to a computer and processed in Kubios software to extract the HRV indices during the most stable stretch of 256 points. The on and off kinetics will be obtained during a 180-second stretch of the rest-start transition (on) and recovery (off) by an exponential model applied to HR beat by beat in the CardioKin 1.2 software.Expected results: We expect that patients with COPD will have poor functional performance, impairment of cardiac autonomic behavior and slower response of HR on and off kinetics, as well as worse outcomes, depending on the severity of the disease.