TABLE 2.

Size of puncture and penumbra of tissue blanching measured under microscopy comparing radiofrequency-assisted needle and guidewire punctures in different cardiac tissue in freshly explanted pig hearts

Tissue	Electrified traversals							Mechanical traversals
		Needle electrical, n = 18			Astato electrical (tip), n = 18			Needle mechanical, n = 9	Astato mechanical (back-end), n = 9
Atrial septum	Hole (mm)	1.11 ± 0.40			0.37 ± 0.08		P = .009	0.63 ± 0.11	0.19 ± 0.16	P = .01
	Penumbra (mm)	3.62 ± 1.23			0.72 ± 0.29		P = .003	Negligible	Negligible
				Subgroup
		Needle 50 W, n = 9	Needle 15W, n = 9		Astato 50 W, n = 9	Astato 15 W, n = 9
	Hole (mm)	0.99 ± 0.38	1.24 ± 0.46	P = .65	0.39 ± 0.11	0.36 ± 0.05	P = .80
	Penumbra (mm)	3.68 ± 0.74	3.57 ± 1.80	P = .89	0.73 ± 0.22	0.70 ± 0.40	P = .93
Ventricular septum	Hole (mm)	1.24 ± 0.24			0.45 ± 0.05		P < .001	1.07 ± 0.24	0.13 ± 0.23	P = .01
	Penumbra (mm)	5.30 ± 1.16			0.75 ± 0.20		P < .001	Negligible	Negligible
				Subgroup
		Needle 50 W, n = 9	Needle 15W, n = 9		Astato 50 W, n = 9	Astato 15 W, n = 9
	Hole (mm)	1.11 ± 0.24	1.37 ± 0.20	P = .08	0.47 ± 0.02	0.42 ± 0.06	P = .38
	Penumbra (mm)	5.82 ± 0.44	4.77 ± 1.52	P = .44	0.86 ± 0.15	0.63 ± 0.19	P = .14
Aorta	Hole (mm)	0.88 ± 0.16			0.29 ± 0.12		P < .001	0.70 ± 0.11	0.12 ± 0.12	P = .007
	Penumbra (mm)	2.77 ± 1.20			0.59 ± 0.15		P = .005	Negligible	Negligible
				Subgroup
		Needle 50 W, n = 9	Needle 15W, n = 9		Astato 50 W, n = 9	Astato 15 W, n = 9
	Hole (mm)	0.89 ± 0.15	0.87 ± 0.15	P = .92	0.33 ± 0.12	0.25 ± 0.12	P = .35
	Penumbra (mm)	3.12 ± 1.67	2.41 ± 0.68	P = .38	0.58 ± 0.17	0.60 ± 0.17	P = .04

A P value of <.05 was considered statistically significant.