Table 1– Linear correlations between ejection fraction (EF) and time-domain variability of breathing variables during maximal cardiopulmonary exercise testing
EFVEVTfR
sd/nRMSSD/nsd/nRMSSD/nsd/nRMSSD/n
r−0.531−0.511−0.442−0.452−0.507−0.510
p-value0.0340.0430.0760.0680.0370.036
  • VE: minute ventilation; VT: tidal volume; fR: respiratory frequency; RMSSD: root mean square successive differences; n: number of breaths.