QT Interval Variability Index and QT Interval Duration in Different Sleep Stages: Analysis of Polysomnographic Recordings in Nonapneic Male Patients

Table 2

Characteristics of rate corrected QT intervals in sleep stages.

Variables	Awake	NREM	REM
QTc Bazett mean (ms)	383.7 ± 18.4	384.7 ± 19.9	388.8 ± 19.9
QTc Lin α min mean (ms)	376.2 ± 22.1	389.7 ± 21.7	384.2 ± 21.6
QTc Par α min mean (ms)	376.0 ± 22.3	389.6 ± 21.7	384.1 ± 21.7
QTc Lin α 0.2 mean (ms)	374.5 ± 24.6	389.3 ± 23.0	382.0 ± 23.8
QTc Par α 0.2 mean (ms)	377.9 ± 18.6	387.3 ± 18.9	384.5 ± 19.8

Data are expressed as means ± SD; NREM: nonrapid eye movement sleep stage; REM: rapid eye movement sleep stage; QTc Bazett: rate corrected QT interval based on Bazett’s formula; QTc Lin α min: rate corrected QT interval based on linear regression formula α minimum; QTc Par α min: rate corrected QT interval based on parabolic regression formula α minimum; QTc Lin α 0.2: rate corrected QT interval based on linear regression formula α 0.2; QTc Par α 0.2: rate corrected QT interval based on parabolic regression formula α 0.2.