Final answer:
A 'step up' in [O2] from RA to RV after an MI often indicates a ventricular septal defect (VSD), where oxygen-rich blood from the LV crosses into the RV, a serious condition requiring prompt medical attention.
Step-by-step explanation:
The question is concerning a potential complication of a myocardial infarction (MI) or heart attack. Specifically, the student is inquiring about a 'step up' in oxygen concentration ([O2]) from the right atrium (RA) to the right ventricle (RV). In a healthy heart, there should not be a significant difference in oxygen levels between these two chambers. However, after an MI, particularly if a ventricular septal defect (VSD) occurs, oxygenated blood from the left ventricle (LV) can flow into the RV due to the pressure difference, causing a 'step up' in oxygen levels detectable in the RV. This condition is a severe complication that needs immediate medical attention.
In simpler terms, if there is a 'step up' in oxygen concentration from the RA to the RV, it is likely indicative of a complication such as a VSD, which allows oxygen-rich blood to mix with oxygen-poor blood. This abnormal mixing can be detected through cardiac catheterization or echocardiography and requires prompt diagnosis and management to prevent further complications.
A 'step up' in oxygen concentration from RA to RV post-MI can indicate a serious complication such as a VSD, which allows oxygen-rich blood to leak into the RV, necessitating immediate medical intervention.