Table 2.

ECG characteristics at baseline and at 5-year follow-up in patients with AS, stratified by sex

	Female (n=79)				Male (n=93)
	Baseline	Follow-up	Change	P value	Baseline	Follow-up	Change	P value
ECG measurements
Heart rate, beats/min	66 (59, 73)	65 (60, 73)	1 (−4, 7)	0.351	64 (57, 73)	65 (58, 73)	1 (−6, 7)	0.938
PR interval*, ms	160 (140, 170)	158 (146, 172)	4 (−4, 10)	0.029	170 (160, 180)	173 (156, 189)	4 (−4, 12)	0.013
QRS interval†, ms	80 (76, 90)	82 (76, 90)	1 (−4, 9)	0.149	90 (80, 100)	91 (86, 100)	3 (−4, 8)	0.004
QTcB‡, ms	410 (393, 426)	411 (398, 422)	4 (−9, 15)	0.173	399 (386, 417)	404 (388, 422)	5 (−10, 22)	0.056
Heart rhythm, n (%)
Sinus	77 (97.5)	78 (98.7)	n.a.	n.a.	90 (96.8)	89 (95.7)	n.a.	n.a.
Bradycardia	3 (3.8)	4 (5.1)			6 (6.5)	5 (5.4)
Tachycardia	0 (0.0)	0 (0.0)			2 (2.2)	2 (2.2)
Atrial fibrillation	0 (0.0)	0 (0.0)			2 (2.2)	2 (2.2)
Pacemaker rhythm	0 (0.0)	1 (1.3)			1 (1.1)	2 (2.2)
Other	2 (2.5)	0 (0.0)			0 (0.0)	0 (0.0)

Data are expressed as median (Q1, Q3) or number (%) and presented for 172 patients if not stated otherwise. Comparison between ECG measurements at baseline and follow-up is calculated by related-samples Wilcoxon signed-rank test.

*n=169 at start, n=167 at follow-up.

†n=171 at start, n=170 at follow-up.

‡QTcB is the heart rate-corrected QT interval according to Bazett; n=171 at start, n=168 at follow-up.

AS, ankylosing spondylitis; n.a., not applicable; Q1, 25th percentile; Q3, 75th percentile.