Table 1.
Baseline clinical and laboratory characteristics according to the mean serum ferritin during the past 5 years.
Table 2.
Heart rate variability parameters according to the mean serum ferritin during the past 5 years.
Fig 1.
The scatter plots for the correlation between HRV [1) low frequency (upper row), 2) high frequency (middle row) and 3) ASDNN (lower row)] and hemoglobin and cardiac T2*.
A: whole model of multiple linear regression analysis; B: the correlation between HRV and cardiac T2*; C: the correlation between HRV and hemoglobin. ASDNN, the average of the standard deviation of all R-R intervals for all 5-minute segments in the 24-hour recordings.
Fig 2.
Receiver operative characteristic (ROC) curve analysis of the mean ferritin in the last 12 months (A) and ASDNN (B) for predictors of the cardiac T2* ≤20 ms.
ASDNN, the average of the standard deviation of all R-R intervals for all 5-minute segments in the 24-hour recordings.
Table 3.
The correlations between HRV parameters and mean hemoglobin during the last 12 months, mean serum ferritin during the last 12 months, mean serum ferritin during the past 5 years, maximum serum ferritin during the past 5 years, NTBI and cardiac T2*.
Fig 3.
Graphing display comparing the frequency domains of HRV (LF, HF and LF/HF ratio) according to cardiac T2*.
LF, low frequency power; HF, high frequency power. *—p<0.05 vs. cardiac T2*<20 ms; #—p<0.05 for cardiac T2*>20 ms vs. normal controls.
Fig 4.
Graphing display comparing the time domains of HRV (SDNN, SDANN, ASDNN and rMSSD) according to cardiac T2*.
SDNN, the standard deviation of all normal sinus R-R intervals in the entire 24-hour recording; SDANN, the standard deviation of all average normal sinus R-R intervals for all 5-minute segments in the 24-hour recordings; ASDNN, the average of the standard deviation of all R-R intervals for all 5-minute segments in the 24-hour recordings; rMSSD, the root mean square of the mean of the squared differences of two consecutive R-R intervals in the 24-hour recordings. *—p<0.05 vs. cardiac T2*<20 ms; #—p<0.05 for cardiac T2*>20 ms vs. normal controls.