The coronary sinus will dilate with an increase in which of the following?

The dilation of the coronary sinus is closely linked to changes in right atrial pressure. When right atrial pressure increases, as seen in conditions such as heart failure or certain forms of right heart dysfunction, this elevated pressure is transmitted back to the coronary sinus. The coronary sinus serves as a collection point for the venous blood returning from the myocardium. Consequently, when the right atrial pressure rises, it creates a corresponding rise in pressure within the coronary sinus, leading to its dilation.

This connection is fundamental in understanding cardiovascular physiology, as elevated right atrial pressures can be indicative of underlying cardiac issues. In contrast, left atrial pressure primarily affects the pulmonary circulation and can lead to different hemodynamic consequences. Systemic vascular resistance and pulmonary blood flow are relevant factors in the broader context of cardiovascular function, but they do not directly influence the dilation of the coronary sinus in the same way that changes in right atrial pressure do.