TABLE 1.

hES2-hvCAS Action Potential (AP) Parameters in acute hypokalaemia. Data analysis was performed for 1.5 Hz electrical stimulation recordings.

Parameters			Sample	Median	Lower 95% CI	Upper 95% CI	N	p Value
(a) Amplitude (ΔF represents the change in fluorescence intensity)			NormoK	0.888	0.81	0.958	12	*** < 0.001
			hypoK	1.19	1.12	1.32	14
(b) AP Duration (APDx) (Time duration in millisecond from the peak fluorescence intensity to the corresponding fluorescence decay intervals)	x
	30%		NormoK	29.1	27.6	31	13	*** < 0.001
			hypoK	34.9	33	37	15
	50%		NormoK	43.4	41.4	45.8	13	*** < 0.001
			hypoK	51.5	47.4	55.3	15
	70%		NormoK	59	54.4	63.7	13	*** < 0.001
			hypoK	72.6	68	77.2	15
	90%		NormoK	83.5	78.5	87.5	13	*** < 0.001
			hypoK	97.4	92.2	104	15
(c) Time-to-peak/Activation Latency (Time duration in millisecond from the start of the rise of the fluorescence intensity to the peak fluorescence intensity)			NormoK	57.4	54.4	61	14	*** < 0.001
			hypoK	64.1	60.9	66.1	17
(d) Upstroke Velocity (ΔF/millisecond; ΔF represents the change in fluorescence intensity)			NormoK	0.0142	0.0126	0.0169	9	* = 0.023
			hypoK	0.0162	0.0153	0.0168	10
(e) Conduction Velocity (CV) (cm·s−1; AP propagation between two points)	Longitudinal (L) CV		NormoK	7.81	7.01	10.6	9	* = 0.036
			hypoK	7.18	4.99	7.62	7
	Transverse (T) CV		NormoK	5.72	4.83	7.02	12	* = 0.030
			hypoK	4.69	3.93	6.34	11
(f) Anisotropic Ratio (Ratio of LCV to TCV)			NormoK	1.47	1.14	1.77	9	ns = 0.444
			hypoK	1.38	1.11	2.09	8
(g) Effective Refractory Period (millisecond)			NormoK	242	200	275	12	*** < 0.001
			hypoK	165	156	220	13

(h) hvCAS statistics	Sample	Spontaneous	Maximum Capture Frequency (Hz)						Spiral Induction
			N/A (capture at higher frequency)	1	1.5	2	2.5	3
	NormoK	0% (0/14)	1/14 (NC: 0.5, 1), (C: 1.5–3)	0/14	0/14	0/14	1/14	12/14	0% (0/14)
	hypoK	21% (3/14)	5/14 (NC: 0.5–1.5 = 1), (NC: 0.5 = 3), (NC: 0.5–1 = 1)	0/14	0/14	0/14	3/14	6/14	50% (7/14)

NormoK, normokalaemia; hypoK, hypokalaemia; NC, non-capture; C, capture.