Which of the Following Statements Are True of the Cardiac

Which of the following statements are true of the cardiac conduction pathway and electrical activity of the myocardium? (Read carefully and select all of the correct statements.)

A) The electrical events along the pathway are triggered by the mechanical events of the chambers.
B) The AV node depolarizes most rapidly.
C) The heart's natural pacemaker is the sinoatrial (SA) node.
D) The right and left bundle branches are in the interatrial septum.
E) Purkinje fibers are in the walls of the ventricles.
F) The AV bundle (of His) has a slower natural rate of contraction than does the AV nodE.
G) Electrical impulses spread rapidly from cell to cell because of the presence of intercalated discs.
H) The sarcomeres of the myocardium contain the contracting proteins myoglobin and actin.