Table 4.

The P values of rate corrected QT intervals between sleep stages.

Variables	Awake/NREM	Awake/REM	NREM/REM
	P value
QTc Bazett mean	0.81	0.30	0.44
QTc Lin α min mean	0.02	0.16	0.34
QTc Par α min mean	0.02	0.16	0.33
QTc Lin α 0.2 mean	0.02	0.23	0.23
QTc Par α 0.2 mean	0.06	0.19	0.58

Significance of differences between sleep stages: P < 0.05; REM: 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.