Assessing Right Ventricular Preload Changes

An adult patient presents to the emergency department with severe chest pain, diaphoresis, and shortness of breath. The initial assessment reveals a blood pressure of 90/60 mmHg, a heart rate of 120 beats per minute, and cool, clammy skin. The healthcare team is concerned about the possibility of cardiogenic shock due to a suspected myocardial infarction. A central venous catheter is inserted to monitor hemodynamics. Which of the following measurements obtained from the central venous pressure (CVP) monitoring would best indicate a decrease in right ventricular preload?