Multiple choice Which of the following is/are the pace setter(s) of the human heart? Atrioventricular bundle Papillary muscles Purkinje fibres SA node AV node Reveal answer Fill a bubble to check yourself D Correct answer Explanation The sinoatrial (SA) node is a section of nodal tissue that is located in the upper wall of the right atrium. The SA node is also referred to as the pacemaker of the heart.