DB Week 2

The part you might want to read

If people are interesting in seeing caths, EP or ccu rounds, let me know. I've already taken Danielle and Aniqua, and joined up w/ Jason, so pairs work in cardiology.

Tracking the VSD case

As you all remember from last week, I have been tracking a patient who has a ventricular septal defect. This week, the patient went in for her cath to place an occluder device in the defect. On echo, there was a clear defect near the apex of the heart, so at the time it seemed like it would be straightforward. What I didn't know at the time was that it took 3 echo techs and many tries to actually locate a hole. The only reason they kept trying was because her mermer was drastic.

At the start, the doctors realized that extra permission from her family was needed to perform a balloon angioplasty of her stenoic aortic valve. After the BA, contrast agent was injected near the site detected on the echo. It didn't show up. If anything, it looked like there was a hole more central in the septum. They were able to interrogate a hole after about an hour of poking and calling in a trans-esophogial echo. Upon injecting contrast, there was obviously still a leak, in fact the leak was more obvious than before! Ultimately, in terms of heart efficiency, the procedure did seem to help. She was removed from balloon pump support and appeared to be stable. However, that night she became hypotensive (~70/20) and went in to afib right when I went to rounds in the morning.

I watched her post op echo live. Again, the tech had a very hard time visualizing the defect and the occulder. It was great to witness the occuder in place, seeing the results of the cath first hand. There was still a clear leak around the apical side of the occulder. She was put back on the balloon pump and continues to need support. If she does not stabalize soon, the doctors will need to inform the family that they will not be able to stabilize her.

Mapping Cardiac Electrophysiology (EP)

Patients require EP mapping when they have dead heart tissue that creates abhorrent electrical circuits. The heart is mapped to find the tissue, which can then be burned using radiofrequency ablation.

The EP lab looks like the cath lab 100yrs in the future. They use a technique called stereotaxis where two large magnets are used to guide a metal catheter inside the patient's heart. The doctor need simply control the vector of the magnetic field with a mouse pointer, and the insertion and withdrawal of the catheter with the mouse wheel. Stereotaxis allows the EP lab to map the electrical properties of the heart point by point onto the patient's heart geometry, which can be initially be obtained by echo slices and is refined as the doctor probes the heart.

Interestingly, the EP lab has the ability to induce arrhythmias by pacing (shocking) the patient's heart. Before cath insertion, the patient demonstrated several PVCs, indicating that there were several possible sources of arrhythmia. At one point, they induced a ventricular tachycardia that caused the heart to completely destabilize. The doc asked "is he out?" and before the nurses could answer, he proceeded to say "Shock him." The patient was defibrillated. Jason Jones and I thought this was insane, to be euphemistic.

This happened 3 times in the procedure, which took 5 hours. While his VT was harder to induce by the end of the surgery, he was sent back the next day to have an ICD (intracardiac defibrillator).

I saw the ICD implant, finally getting into a surgical room (not quite an OR). At the end of the install, a VT was induced and the patient's new ICD dutifully shocked his heart back to normal.