Table 3.

Regression coefficient (SE) of HR-corrected QT measures associated with 10-μg/m³ increment of PM_2.5 with additional adjustment for HRV variables.^a

	QTI				QTcB (msec)				QTcF (msec)
	HF	LF	SDNN	RMSSD	HF	LF	SDNN	RMSSD	HF	LF	SDNN	RMSSD
Lag 0 (same time)	0.08 (0.04)**	0.07 (0.04)**	0.09 (0.04)**	0.08 (0.04)**	0.05 (0.08)	0.05 (0.08)	0.07 (0.08)	0.05 (0.08)	−0.05 (0.05)	−0.05 (0.05)	−0.05 (0.05)	−0.05 (0.05)
Lag 1 (30 min)	0.04 (0.02)*	0.04 (0.02)*	0.04 (0.02)*	0.04 (0.02)*	0.01 (0.06)	0.01 (0.06)	0.02 (0.06)	−0.01 (0.06)	−0.04 (0.04)	−0.04 (0.04)	−0.04 (0.04)	−0.04 (0.04)
Lag 2 (60 min)	0.01 (0.02)	0.01 (0.02)	0.01 (0.02)	0.02 (0.02)	−0.01 (0.06)	−0.01 (0.06)	−0.01 (0.06)	−0.03 (0.06)	−0.02 (0.04)	−0.02 (0.04)	−0.02 (0.04)	−0.03 (0.04)
Lag 3 (90 min)	−0.001 (0.03)	0.001 (0.03)	−0.01 (0.03)	0.01 (0.03)	−0.003 (0.07)	0.0004 (0.07)	−0.01 (0.07)	−0.03 (0.06)	0.003 (0.04)	0.004 (0.04)	−0.002 (0.04)	−0.01 (0.04)
Lag 4 (120 min)	−0.001 (0.03)	0.001 (0.03)	−0.01 (0.03)	0.01 (0.03)	0.02 (0.07)	0.03 (0.07)	0.02 (0.07)	−0.004 (0.07)	0.03 (0.04)	0.03 (0.04)	0.02 (0.04)	0.02 (0.04)
Lag 5 (150 min)	0.01 (0.03)	0.01 (0.03)	0.004 (0.03)	0.02 (0.03)	0.08 (0.07)	0.08 (0.07)	0.07 (0.07)	0.05 (0.07)	0.05 (0.04)	0.06 (0.04)	0.05 (0.04)	0.04 (0.04)
Lag 6 (180 min)	0.03 (0.03)	0.04 (0.03)	0.03 (0.03)	0.04 (0.03)	0.15 (0.07)**	0.15 (0.07)**	0.15 (0.07) **	0.13 (0.07)**	0.08 (0.04)**	0.08 (0.04)**	0.08 (0.04)**	0.08 (0.04)*
Lag 7 (210 min)	0.07 (0.04)*	0.07 (0.04)*	0.07 (0.04)*	0.08 (0.04)*	0.25 (0.09)#	0.25 (0.09)#	0.25 (0.09)#	0.24 (0.09)#	0.12 (0.05)**	0.12 (0.05)**	0.12 (0.05)**	0.11 (0.05)**
Cumulative	0.24 (0.14)*	0.25 (0.14)*	0.23 (0.14)*	0.29 (0.13)**	0.56 (0.40)	0.57 (0.40)	0.56 (0.40)	0.39 (0.40)	0.17 (0.25)	0.18 (0.25)	0.17 (0.25)	0.11 (0.25)

^aAdjusted for age, sex, race, temperature, relative humidity, diabetes, hypertension, CVD, and each of the HRV indices.

^*p < 0.1.

^**p < 0.05.

^#p < 0.01.