Table 2.

Suggested functions of TTX-sensitive Na⁺ channels in the mammalian myocardium. Adapted from^51,63.

Suggested function		Species	References
Control of heart rate	Contribution to slow diastolic depolarization	Rabbit	75,76
	Contribution to automaticity and heart rhythm, possible contribution to sick sinus syndrome	Mouse	51,57
	Contribution to pacemaking and sinus node conduction	Mouse	44,77
Cardiac conduction and action potential shape	Higher expression of TTX-sensitive Na+ channels in Purkinje fibres compared to ventricular cells, suggested role for safeguarding conduction	Dog	42
	Expression of Nav1.4 in cardiac Purkinje myocytes, important clinical role in arrhythmia	Dog	78
Cardiac contractility	Suggested role for excitation-contraction coupling	Mouse Guinea pig	55,56,79
	Suggested role for action potential propagation in ventricular cardiomyocytes	Mouse Rat	53,56,80