TABLE 1.

ECG measurements for each electrode type in terms of median values and 25th and 75th percentiles (in brackets).

	Non-breathable tattoo	Breathable tattoo	Gelled Ag/AgCl
QRS amplitude (mV)	3.23	3.16	2.96
	[2.96; 3.28]	[2.85; 3.25]	[2.85; 3.21]
P duration (ms)	117.19	119.14	117.19
	[113.28; 125.00]	[113.28; 125.00]	[113.28; 125.00]
QRS duration (ms)	83.98	97.66	85.94
	[66.41; 101.56]	[66.41; 101.56]	[66.41; 101.56]
T duration (ms)	181.64	175.78	189.45
	[171.88; 195.31]	[167.97; 187.50]	[179.69; 199.22]
PQ interval (ms)	158.20	156.25	156.25
	[152.34; 164.06]	[144.53; 164.06]	[152.34; 160.16]
RR interval (ms)	914.06	913.82	912.60
	[885.25; 1,050.78]	[885.25; 1,050.78]	[885.25; 1,050.78]
QTc interval (ms)	388.52	388.38	386.08
	[366.55; 393.76]	[377.15; 396.61]	[365.83; 396.42]