A couple interesting questions came to my mind over the last week, and there doesn’t seem to be any clear explanations for why. This seems to be an unusual departure from last year where all the physiology was pretty straight forward, albeit complicated, there were few questions left unanswered.

We learned a rule of thumb that most superior MI’s are high and fast, in terms of blood pressure and heart rate, respectively. And conversely, we learned that inferior MI’s are low and slow. In our small groups, our instructor was a little unsure about why, so this is the best explanation I could find. Inferior MI’s are due to a blockage in the proximal portion of the RCA which is responsible for blood supply to the SA node. The SA artery can be also sometimes supplied by the CFX from the left coronary, which would not cause a decrease in heart rate.