The use of invasive hemodynamic monitoring is based on the following principal factors:
1. Difficulty in interpreting clinical and radiographic findings of pulmonary congestion even after a thorough review of noninvasive studies such as an echo-cardiogram.
2. Need for identifying noncardiac causes of arterial hypotension, particularly hypovolemia.
3. Possible contribution of reduced ventricular compliance to impaired hemodynamics, requiring judicious adjustment of intravascular volume to optimize left ventricular filling pressure.
4. Difficulty in assessing the severity and sometimes even determining the presence of lesions such as mitral regurgitation and ventricular septal defect when the cardiac output or the systemic pressures are depressed.
5. Establishing a baseline of hemodynamic measurements and guiding therapy in patients with clinically apparent pulmonary edema or cardiogenic shock.
6. Underestimation of systemic arterial pressure by the cuff method in patients with intense vasoconstriction.
The prognosis and the clinical status of patients with STEMI relate to both the cardiac output and the pulmonary artery wedge pressure. Patients