Cigarette Smoking Is Associated with Prolongation of the QTc Interval Duration in Patients with Type 2 Diabetes Mellitus

Table 3

Mean values (±SD) of time-domain parameters of HRV during 24-hour, day, and night periods.

Variable (ms)	Chronic smokers	Nonsmokers	𝑃
SDNN 24 hours	114.98 ± 33.05	123.32 ± 39.04	0.348
SDNN day	92.64 ± 30.64	97.91 ± 26.15	0.452
SDNN night	83.43 ± 27.55	90.41 ± 30.68	0.331
PNN30 24 hours	13.79 ± 11.79	13.58 ± 10.99	0.94
PNN30 day	11.70 ± 11.45	10.06 ± 9.3	0.523
PNN30 night	17.03 ± 14.71	20 ± 15.81	0.43
RMSSD 24 hours	28.41 ± 17.28	28.51 ± 14.18	0.979
RMSSD day	26.51 ± 16.07	24.41 ± 12.36	0.553
RMSSD night	30.61 ± 22.3	34.01 ± 18.77	0.502
SDANN 5 min 24 hours	104.34 ± 31.65	112.5 ± 40.04	0.358
SDANN 5 min day	82.04 ± 30.4	86.97 ± 27.95	0.493
SDANN 5 min night	62.19 ± 20.94	67.69 ± 31.97	0.407

SDNN: standard deviation of all normal-to-normal RR intervals; PNN30: number of pairs of adjacent NN intervals differing >30 ms in the entire recording divided by the total number of all NN intervals; RMSSD: the square root of the mean of the sum of the squares of differences between adjacent NN intervals; SDANN: 5 min, standard deviation of the averages of NN intervals in all 5-minute segments of the entire recording.