Heart rate recovery after the 6 min walk test rather than distance ambulated is a powerful prognostic indicator in heart failure with reduced and preserved ejection fraction: a comparison with cardiopulmonary exercise testing

Abstract

Aims Heart rate recovery (HRR) appears to be a robust prognostic marker in heart failure (HF). When using the 6 min walk test (6MWT) in HF, distance ambulated is generally the reference prognostic variable. We hypothesized that HRR after the 6MWT would be a better prognostic measure than distance ambulated. Methods and results A 6MWT and cardiopulmonary exercise testing (CPX) were randomly performed in 258 HF patients [216 HF with reduced EF (HFrEF) and 42 HF preserved EF (HFpEF)], after which HRR was measured. HRR was defined as the difference between heart rate at peak exercise and 1 min following test termination. Patients were assessed for major cardiac events during a mean follow‐up period of 22.8 ± 22.1 months. There were 50 major cardiac events during the tracking period. Univariate Cox regression analysis results identified HRR after both the 6MWT and CPX as a significant (P < 0.001) predictor of adverse events. Multivariate Cox regression analysis revealed that dichotomized HRR after the 6MWT and CPX was the strongest predictor of survival (χ2 61.1 and 53.8, respectively; P < 0.001), with LVEF (residual χ2 6.1, P < 0.05) adding significant prognostic value to the 6MWT model and ventilatory efficiency (the VE/VCO2 slope) (residual χ2 6.6, P < 0 .05) adding significant prognostic value to the CPX model. Conclusions HRR after the 6MWT is a powerful prognosticator that performs similarly to HRR after maximal exercise. If confirmed in subsequent studies, 6MWT HRR should replace 6MWT distance as the reference criterion 6MWT measure to consider when grading cardiovascular risk in HF patients.

Clinical and Hemodynamic Correlates and Prognostic Value of VE/VCO 2 Slope in Patients With Heart Failure With Preserved Ejection Fraction and Pulmonary Hypertension

“…A few others studied the value of CPX in patients with HFpEF. [20][21][22] Guazzi et al compared CPX parameters with multiple variables between an HFrEF and an HFpEF population. 20 Although that study showed that the VE/VCO2 slope represents HFpEF severity, no relationship between the VE/VCO2 slope and mortality was studied.…”

“…They showed that in the combined population with predominantly HFrEF patients, the VE/VCO2 slope was a significant prognostic parameter in the 6-minute walk test, and they found that the VE/VCO2 slope was the only predictor of major cardiac events. 21 Nedeljkovic et al studied the value of CPX as a diagnostic tool for HFpEF. They concluded that the VE/ VCO2 slope could be a reliable test to diagnose HFpEF in an early stage, but they did not investigate the possible association between VE/VCO2 and mortality.…”

Heart Rate Recovery After 6-min Walking Test Predicts Acute Exacerbation in COPD

“…However, HRR 1 after the 6MWT in COPD as a prognostic factor has never been reported. This is a tangible clinical finding given that the 6MWT is a widely used, simple test to apply into the clinical scenario (12).…”

Training the Left Ventricle With Preserved Ejection Fraction or Cardiorespiratory Fitness?

“…20 The other determinant of Fick principle is O 2 extraction, a biological phenomenon related to O 2 delivery and diffusion from capillaries to mitochondria. When O 2 is adequately dispatched by cardiac output, its extraction depends on the amount of blood flow redistribution to vascular beds of exercising muscles and several molecular facilitating mechanisms, including PO 2 , the Hb concentration and the pressure of O 2 corresponding to the 50% of Hb half saturation with O 2 (P 50 ).…”