Table 6.
Correlations between HRV parameters and patient characteristics.
| Share of the Autonomous Components in the Modulation of HRV Parameters | |||||||
|---|---|---|---|---|---|---|---|
| Overall HRV or Sympathetic and Parasympathetic Nervous System Activities | Parasympathetic Nervous System Activity | ||||||
| HRV Parameters | SDNN | HRV Index | Low Frequency | Total Power | rMSSD | pNN50 | High Frequency |
| Group characteristic | |||||||
| Age at the time of Fontan operation |
R = −0.379,
p = 0.039 |
R = −0.250, p = 0.183 |
R = −0.074, p = 0.697 |
R = −0.153, p = 0.421 |
R = 0.270, p = 0.149 |
R = −0.422,
p = 0.020 |
R = −0.047, p = 0.805 |
| Age during the study |
R = −0.426,
p = 0.019 |
R = −0.217, p = 0.25 |
R = −0.31, p = 0.094 |
R = −0.432,
p = 0.017 |
R = −0.061, p = 0.749 |
R = −0.481,
p = 0.007 |
R = −0.205, p = 0.276 |
| Echocardiography | |||||||
| Ejection fraction of the systemic ventricle |
R = 0.584,
p = 0.001 |
R = 0.424,
p = 0.02 |
R = 0.347, p = 0.06 |
R = 0.453,
p = 0.012 |
R = 0.032, p = 0.104 |
R = 0.638,
p = 0.001 |
R = 0.281, p = 0.132 |
| Chronotropic parameters | |||||||
| HRR | R = −0.137, p = 0.471 |
R = −0.411,
p = 0.023 |
R = −0.221, p = 0.240 |
R = −0.264, p = 0.159 |
R = −0.323, p = 0.082 |
R = −0.262, p = 0.162 |
R = −0.193, p = 0.307 |
| Chronotropic index | R = 0.220, p = 0.243 |
R = 0.330, p = 0.075 |
R = 0.332, p = 0.073 |
R = 0.333, p = 0.072 |
R = 0.291, p = 0.118 |
R = 0.419,
p = 0.021 |
R = 0.164, p = 0.386 |
| CPET parameters | |||||||
| Exercise time | R = 0.318, p = 0.086 |
R = 0.709,
p < 0.001 |
R = 0.544,
p = 0.002 |
R = 0.45,
p = 0.013 |
R = −0.099, p = 0.601 |
R = 0.440,
p = 0.015 |
R = 0.38,
p = 0.038 |
| Peak heart rate | R = 0.262, p = 0.163 |
R = 0.485,
p = 0.007 |
R = 0.384,
p = 0.036 |
R = 0.375,
p = 0.041 |
R = 0.377,
p = 0.040 |
R = 0.394,
p = 0.031 |
R = 0.277, p = 0.138 |
| Peak VO2 per kg |
R = 0.404,
p = 0.027 |
R = 0.607,
p < 0.001 |
R = 0.394,
p = 0.031 |
R = 0.360, p = 0.051 |
R = 0.142, p = 0.453 |
R = 0.524, p = 0.003 |
R = 0.290, p = 0.119 |
| Peak VO2, %N | R = 0.137, p = 0.469 |
R = 0.541,
p = 0.002 |
R = 0.233, p = 0.216 |
R = 0.185, p = 0.328 |
R = −0.016, p = 0.933 |
R = 0.222, p = 0.238 |
R = 0.077, p = 0.687 |
| VE |
R = 0.434,
p = 0.017 |
R = 0.369,
p = 0.045 |
R = 0.274, p = 0.143 |
R = 0.249, p = 0.184 |
R = 0.076, p = 0.690 |
R = 0.298, p = 0.110 |
R = 0.377,
p = 0.04 |
| VE/VCO2 | R = −0.012, p = 0.951 |
R = −0.424,
p = 0.019 |
R = −0.240, p = 0.202 |
R = −0.156, p = 0.411 |
R = 0.119, p = 0.530 |
R = −0.305, p = 0.102 |
R = −0.197, p = 0.296 |
| Laboratory tests | |||||||
| GGTP | R = −0.322, p = 0.083 |
R = −0.245, p = 0.192 |
R = −0.385, p = 0.036 |
R = −0.346, p = 0.061 |
R = −0.154, p = 0.415 |
R = −0.368,
p = 0.046 |
R = −0.309, p = 0.096 |
Abbreviations: CPET, cardiopulmonary exercise test; GGTP, γ-glutamyl transpeptidase; HRR, heart rate reserve; HRV, heart rate variability; peak VO2 per kg, peak oxygen uptake per kilogram; peak VO2 (%N), percentage of predicted value for peak oxygen uptake; pNN50, percentage difference between adjacent NN intervals of >50 ms duration; rMSSD, root mean square of the differences of successive NN intervals; SDNN, standard deviation of all NN intervals; VE, minute ventilation; VE/VCO2, peak ventilatory equivalent of CO2. Significant results in bold.