Table 5.

Relationship between HRV risk score according to cut–off value and occurrence of atrial fibrillation.

Variable	HR (95% CI)	P value
HF ≥ 11.1 (ms)	3.084 (1.653–5.753)	< 0.001
rMSSD ≥ 29.5 (ms)	2.528 (1.378–4.638)	0.003
pNN50 ≥ 7.0 (%)	2.261 (1.223–4.179)	0.009
One or more risk of HRVa	3.261 (1.648–6.452)	0.001
Risk score of HRVb
0 (n = 405)	1.0 (reference)
1 (n = 65)	4.249 (1.647–10.963)	0.003
2 (n = 54)	0.688 (0.086–5.173)	0.699
3 (n = 258)	3.597 (1.770–7.310)	< 0.001
PACs ≥ 145 beats for 24 h	3.788 (2.031–7.068)	< 0.001

HRV, heart rate variability; HF, high frequency; rMSSD, square root of the mean squared differences of successive NN interval; pNN50, the percentage of RR intervals that are more than 50 ms different from the previous interval; PAC, premature atrial contraction.

^aIndicates that at least one of the above mentioned abnormal HRV parameters (HF, rMSSD, and pNN50) were present.

^bSum of the above mentioned abnormal HRV parameter (HF, rMSSD, and pNN50).