Table 2.

The R-R intervals, the SDNN and the RMSSD of the studied group

	Myocardial injury group (n = 42)	Non-myocardial injury group (n = 145)	P value
First day
R-R intervals (ms)	498.09 ± 42.28	556.01 ± 29.84	0.001*
SDNN (ms)	64.17 ± 10.91	101.36 ± 23.91	0.003*
RMSSD (ms)	17.27 ± 2.83	26.68 ± 5.33	0.003*
Second day
R-R intervals (ms)	535.65 ± 43.00	618.61 ± 52.16	0.004*
SDNN (ms)	67.07 ± 12.78	100.07 ± 26.11	0.001*
RMSSD (ms)	18.05 ± 2.89	28.36 ± 5.42	0.002*
Third day
R-R intervals (ms)	584.96 ± 45.32	634.96 ± 42.86	0.003*
SDNN (ms)	70.63 ± 13.77	106.84 ± 28.00	0.004*
RMSSD (ms)	19.51 ± 3.36	27.19 ± 5.63	0.006*
Fourth day
R-R intervals (ms)	522.38 ± 43.64	609.29 ± 36.38	0.007*
SDNN (ms)	74.94 ± 13.99	100.49 ± 19.99	0.009*
RMSSD (ms)	18.41 ± 2.69	26.95 ± 5.39	0.001*
Fifth day
R-R intervals (ms)	653.41 ± 28.33	565.68 ± 53.17	0.153
SDNN (ms)	69.87 ± 12.23	92.80 ± 23.21	0.008*
RMSSD (ms)	20.62 ± 4.04	28.12 ± 5.38	0.008*

Data are expressed as mean ± SD

SDNN Standard Deviation of NN intervals, RMSSD Root Mean Square of the Successive Differences

^* p < 0.05 is statistically significant