Food for thought (and atherosclerosis)
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. There seems to be more gray areas when it comes to pathophysiology.
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.
We also learned about a concept called “masked hypertension.” As you might know, BP can change throughout the day. When patients go into their doctor’s office, it can be artificially high due to stress of being in that environment. Conversely, some people can get an artificially low blood pressure. We were told that it’s not due to differences in anxiety (i.e., some people are just less anxious in doctor’s offices than others), because it also wouldn’t make much sense for some people to feel more nervous at home. I suspected that perhaps there might be some other domestic problems that would cause their BP to rise at home, but our professor told me afterward that we think that it might be due to differences in sympathetic activity. If anyone finds out why, let me know.
