The sequence of travel by an action potential through the heart is

1- atrioventricular node, sinoatrial node, atrioventricular bundle, bundle branches, Purkinje fibers.

2- sinoatrial node, atrioventricular node, atrioventricular bundle, bundle branches, Purkinje fibers.

3- atrioventricular node, sinoatrial bundle, atrioventricular node, bundle branches, Purkinje fibers.

4- atrioventricular bundle, atrioventricular node, sinoatrial node, bundle branches, Purkinje fibers.

5- Purkinje fibers, atrioventricular bundle, atrioventricular node, sinoatrial node, bundle branches.