Which finding would be key in differentiating acute right ventricular failure from other causes in a patient with suspected PAH?

Elevated central venous pressure (CVP) is a critical finding that indicates acute right ventricular failure, particularly in the context of pulmonary arterial hypertension (PAH). In acute right ventricular failure, the right ventricle struggles to pump blood effectively, leading to an increase in pressure within the right atrium and subsequently the central venous system. This elevation in CVP reflects the direct consequence of decreased right ventricular output and the resultant backlog of blood.

In patients with PAH, the right ventricle faces increased afterload due to elevated pressures in the pulmonary arteries. When the right ventricle fails acutely, the ability to maintain adequate forward blood flow diminishes, causing venous congestion and resultant high CVP. This finding is essential to differentiate acute right ventricular failure from other conditions, such as left-sided heart failure, where elevated left atrial pressures would be more relevant.

Patients with isolated right ventricular failure often retain a normal cardiac output, especially in the early stages, because the body compensates for the right ventricular dysfunction by altering heart rate and contractility. Meanwhile, systemic vascular resistance may vary based on patient conditions and does not selectively point towards right ventricular failure in the same definitive manner as CVP. Therefore, elevated CVP uniquely signals