Table 1.

Suppressed development of intramural coronary arteries and periarterial Purkinje fibers by NC ablation

Hearts	Vv, %
	Intramural coronary arteries	Periarterial Purkinje fibers
NC-ablated	0.4 (0.06)	0.1 (0.02)
Control	1.2 (0.11)	0.3 (0.03)
Unpaired t test	P < 0.01	P < 0.01
Mann–Whitney	P < 0.0001	P < 0.0001

Quantitative microstereology reveals significant decreases in the volume density fractions (Vv, expressed as percentages) of cardiac tissue occupied by intramural coronary arterial profiles penetrating ventricular myocardium and periarterial Purkinje fibers in E15 hearts after NC ablation (15). The fractional volumes of coronary arteries and associated Purkinje fibers were scored on immunolabeled histological sections by using a well-established point counting protocol (21). Numbers in parentheses indicate the standard error. Comparisons of mean volume fraction estimates between NC-ablated and control hearts by Student’s t test and nonparametric Mann–Whitney tests are presented as P values.