Final answer:
The SA node is the dominant cardiac pacemaker in healthy patients, initiating the sinus rhythm in the right atrium and triggering heart contractions.
Step-by-step explanation:
The correct statement regarding the SA node is: c) The SA node is the dominant cardiac pacemaker in healthy patients. The sinoatrial (SA) node is a cluster of specialized myocardial conductive cells situated in the superior and posterior walls of the right atrium, near the entry point of the superior vena cava. It has the highest inherent rate of depolarization and is responsible for initiating the sinus rhythm, which is the normal electrical pattern that triggers the contraction of the heart. This rhythm then spreads across the atria to the atrioventricular (AV) node, where it encounters a delay before being transmitted to the ventricles. This pause is crucial as it allows the atria to finish contracting and pumping blood into the ventricles. Statements a) and b) are incorrect because the SA node is located in the right atrium, not the right ventricle, and SA nodal ischemia typically does not occur solely from the occlusion of the left coronary artery. Statement d) is partially inaccurate because the impulses generated by the SA node travel across both the right atrium and the left atrium.