WILTIMS #219: All the fun facts!

It's funny and awkward being at this teenage stage of my medical education. An example is of how my vocabulary has changed in the last year and a half. Words that I once defined as part of my "TIL" facts last year are so familiar that I get in trouble forgetting to defining them to the uninitiated in current posts in this same blog. See below where, when trying to describe a pulmonary embolism, I used the word occlusion, which no one else in the room was able to use in a sentence. So, I've obviously learned a few things (and must make sure to check that I don't overuse jargon, both in this setting and during future patient care).

But at the same time, nearly every day a professor does the same thing to my entire class. She will use a very basic term from her discussed field, something that we simply have never had occasion to learn, and then have to stop and backtrack once she sees the confused looks and quiet whisperings between classmates. Today's word was claudication (just as angina means chest pain, claudication is leg pain).

TIL: There are two different nuclear dyes used in cardiac stress tests to image the heart. They each have their own pros and cons, but one was particularly entertaining. Depending on the location and travel plans of a patient, you may want to use technetium-99mTc instead of thallium-201 because, with the latter, the patient will be "nuclear" for a week. These two drugs have the same radioactive dose, similar cost, and the same effectiveness. But thallium has a longer half-life and will set off nuclear detectors (such as those in high profile airports or the Lincoln tunnel) for a week post-procedure.

Mitral valve prolapse (MVP) can cause premature ventricular contractions (PVCs). MVP is when the mitral valve, between the left atrium and ventricle, is pushed back into the atrium as the ventricle contracts, much like an umbrella inverting in a heavy wind. As it does this, it pulls on the cords and muscles that normally tether the valve in place. These papillary muscles stretch out and stress the wall of the ventricle, which can cause the heart muscle to send out an emergency wave of contraction (that's its somewhat knee-jerk response to pretty much any stress). This wave can result in a single weird beat of the heart, or more seriously trigger a dangerous arrhythmia.

The force parentheses were strong with this one, so lets take it without them first: More people die during or immediately following air travel due to pulmonary embolism as a result of a deep vein thrombosis than of airplane crashes. Ok, got the basic structure? One more time: More people die of pulmonary embolism (the occlusion (blocking off) of an artery in the lungs due to a piece of debris getting lodged in the progressively narrowing blood vessels) as a result of a deep vein thrombosis (a big blood clot forming in a large vein which often breaks off small emboli (chunks of stuff) when agitated (like during air travel)) than of crashes in commercial air travel.

Lastly, you can use right heart catheterization to measure left atrial pressure. This may not seem sensical at first, but hear me out. Think about where a balloon would travel if you let it into the right atrium. First, it would float through the tricuspid valve to the right ventricle. Then it would be pumped through the pulmonary valve to the pulmonary artery. Then it would wander into smaller and smaller arteries as it approaches the lungs before getting lodged (much like the pulmonary embolism we just discussed). Once it's stuck in the lung arteries, the downstream pressure will equalize all the way to the left atrium. This balloon has a sensor on it that measures this pressure and Voila! Left atrial pressure.