Wednesday, February 13, 2013

A VC Day

PennInTouch with a
slightly depressingly-
far-away graduation
Hi everyone! My name is Jessica, and I’m a first year MD-PhD student. I’m from Centreville, Virginia, which is about 20 minutes outside D.C. I did my undergrad at MIT, where I majored in bioengineering and minored in music, and just graduated in June 2012. I’m interested in a bunch of things, both on the research (tissue engineering, microfluidics, computational biology…) and medical (peds, cardiology, neurology…) sides, so I’m not quite (read: not at all) sure what I “want to do” yet, but my expected graduation date is apparently Spring 2020—see screen capture from PennInTouch—so I guess I still have plenty of time to figure it out. This is also my first blog post, so I’m kind of nervous, but here goes:

You may have heard that Penn has something called VC2000, which is like Reunion Hall CSPAN (Reunion Hall is where we have lecture). All of our lectures are recorded and put on VC, so that those who can't attend a lecture in person can watch them from home later. It’s pretty popular!

Anyway, I took advantage of VC recently too, but not to sleep in (although some do); instead, I shadowed at HUP’s electrophysiology lab! It was amazing. The backstory is that we have a project for our Mod 6 Doctoring class called ITAP (Interprofessional Team Assessment Project), where we’re supposed to observe a medical team in action and analyze how they work together. So Thursday morning, Russell (who is on my learning team) and I went up to the 9th floor of Founders in HUP to watch the electrophysiology team do their daily morning meeting. We watched how the team members interacted as they discussed the patients they’d be seeing that day, determined what procedures they’d be doing, and made some decisions as to how certain patients should be cared for. After we’d fulfilled the bulk of our ITAP responsibilities, we stuck around to talk to/do some short interviews with some of the team members (also for ITAP), and of course, to watch the procedures.

First, I went to see an ICD replacement, while Russell headed off to watch an atrial flutter ablation. ICDs (Implantable Cardioversion Defibrillators) are about half-cell-phone-sized, battery-powered generators that use electricity to effectively shock the heart back into normal rhythm when the patient has dangerous irregular heartbeats. Here’s a Youtube video of one in action: 

And here's the corresponding article in Sports Illustrated:

ICDs have a limited lifespan, though, so they need to be replaced every so often. The procedure for replacement was very different from what I expected—only a local anesthetic is used, the incision to take out the old ICD and put in the new one is just a few inches long, and the entire process took about half an hour. Only the generator—not the wires that connect it to the heart—get replaced, and a lot of double- and triple- and quadruple-checking goes on to make sure the wires are reconnected correctly. I didn’t understand much, and it didn’t seem like a good time to interrupt with a million questions, but it looked and sounded like each wire is color-coded, labeled with what part of the heart it’s coming from, and labeled with a serial number to make sure that it connects to the right place in the generator. The patient was actually awake until the very end, when the electrophysiologists induced an irregular rhythm in order to test the new device.

Since the ICD replacement went so smoothly and quickly, I went to find Russell, who was watching an atrial flutter ablation, after it was done. The setup for the atrial flutter ablation reminded me of an airport control tower. Since the ablation done by inserting a catheter into the femoral vein and guiding it up into the heart, X-rays are used for imaging throughout the process. In order to minimize X-ray exposure for the doctors who are doing these procedures every day, one of them is in the room with the patient doing the ablation while another one is in a “control room,” watching and guiding. Everyone inside the procedure room is wearing lead jackets to protect themselves from the X-rays, and the control and procedure rooms communicate via headset.

On every monitor in the control room, a large number of indecipherable squiggles were running across the screen. Luckily for us though, it turns out the ablation procedure includes a 30-minute wait, so during the waiting period the attending paused to explain these squiggles, and what on earth an atrial flutter ablation is anyway.

Image adapted from the National Heart, Lung
and Blood Institute. Original image here:
Heart muscles contract when they are stimulated by electricity, which is made in some special heart cells and is sent throughout the muscles. Normally, the electrical current passes through the atria in the upper part of the heart once, causing them to contract and pump blood into the ventricles, which then pump blood into the body. However, in atrial flutter, the electricity keeps on going around and around the atrium instead of disappearing. As a result, even though the atria contract more often, each contraction is less efficient, and this can cause all sorts of problems, including blood clots. To fix the problem, electrophysiologists can make a series of tiny burns in the wall of the atrium; this is called ablation. Then in the future, if the current tries to go around the atrium instead of stopping like it should, the electricity will get stuck where the burns were placed, and the atria will continue to contract normally.

When the half-hour wait was over, it was time to see whether the ablation had worked. To do this, the doctors stimulated the heart muscle with electricity in one location, and then measured how long it took to get to two other places in the atria. Based on which of these two places “felt” the electricity first, they could tell whether current was still passing through the area they had intended to ablate. To give an idea of the level of precision involved, they were looking at differences on the order of tens of milliseconds—for comparison, test your reaction time here: (average appears to be ~215ms. Guess I'm way below average!). Fortunately, the equipment being used could detect time differences that are much shorter than human reaction times, and they saw the stimulation pattern they expected, which meant that the procedure had worked.

After watching the ablation, we decided it was time to end our brief foray into real life after med school, and headed back to the biomed library to catch up on some rheumatology lectures. Shadowing was great, though; and we learned so much! I loved shadowing in the EP lab, but for those who aren’t as interested in cardiology, Penn also has many other shadowing opportunities, both at HUP and at CHOP—in fact, shadowing in the emergency departments at both hospitals is an established "thing" and is fairly common among our classmates. Some people also just set up shadowing times outside of the emergency departments, with small group preceptors, for example. Whatever your interests, shadowing opportunities are fairly easy to come by here, and definitely worth missing lecture for once in a while!

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