Table 4. The electrocardiographic parameters of the patients one day before and one week after surgery.

	Pre-operative		Postoperative		p-value
	Median	Min–max	Median	Min–max
Heart rate (beats/min)	82	53–127	86.5	64–144	0.606
P-wave amplitude (mV)	1.98	0.81–3.64	1.28	0.64–2.17	< 0.001
P-wave duration (ms)	117.2	57.6–134	98.4	70.8–126	0.001
P-wave dispersion (ms)	50.5	17.2–71.6	30	10–60	< 0.001
P–R interval (ms)	160	110–240	150	90–230	0.063
QRS interval (ms)	90	80–98	90	70–130	0.837
QTc dispersion (ms)	50	10–130	40	10–90	0.437

Max: maximum; Min: minimum; QTc: corrected QT interval.