Week One: Let the Immersing Begin

What a great way to start off immersion. This week was a whirlwind of immersing myself into the clinical setting of cardiology. Dr Gaudino, one of my clinical mentors, along with his fellow were not here this week and therefore I shadowed Dr. Weinsaft, who is a cardiology radiologist and another one of my clinical mentors. After discussing with Dr. Weinsaft that I would like to see as much as possible during my time here in the cardiology unit, he set me up with a variety of very interesting clinical aspects of cardiology including observing a cardiac MRI, rounds in the cardiology ICU, nuclear imaging stress tests, coronary artery stent procedures in the cathlab, and electrophysiology testing.

Each day this week I started off the day by observing rounds in the cardiology intensive care unit. The cases that these doctors were presented with were really challenging. Many of these patients suffered from myocardial infarctions and had very low ejection fraction numbers. Unfortunately, some of these patients even progressed to complete congestive heart failure due to the associated complications of having a heart attack and were waiting for heart transplants. Since my own research back in Ithaca involves cardiac regeneration, it was interesting to be able to see first hand the magnitude of how my own research could potentially help these types of patients in the future. It makes my own research that much more rewarding, knowing I could play a small part in making a difference for these individuals.

After rounds, each day I was able to observe a variety of diagnostic procedures. The first procedure I observed was a cardiac MRI on a patient who suffered from a myocardial infarction. This diagnostic procedure was really interesting as they are able to obtain live images of the heart as it pumps blood throughout the chambers of the heart. Through the use of different contrast dyes, Dr. Weinsaft and his radiology team are able to distinguish areas of the myocardium that are ischemic as well as infarcted (necrotic). This information helps the doctors determine the best course of action for treatment. An example of a cardiac MRI is shown below in Figure 1.


Figure 1: Cardiac MRI example taken from wikipedia.

 Another very interesting imaging procedure involved nuclear imaging stress testing, as shown in  figure 2 below. For this procedure, patients are placed on a treadmill or given specific drugs to "exercise/stress" the heart and injected with a radioisotope (thallium-201) that travel to the heart depending on the proportion of blood that enters the heart and therefore can qualitatively measure blood flow/perfusion within the heart. The test involves taking two image sets using a gamma camera. One set while the patient is at rest and another while being stressed (exercising) to induce a faster heart rates and thus require the heart to work harder. With these images, the clinicians are able to obtain useful information about specific regions in the heart that have lower perfusion. I was able to not only observe this procedure being done but also afterwards with Dr. Weinsaft and his fellows actually read the images themselves. This was an awesome experience due to the fact I was able to watch the entire procedure from the actual acquisition to the diagnosis. We read about 25 different image sets and by the end was able to distinguish some areas that had lower perfusion than the rest. As this procedure is very qualitative, it takes a lot of skill and practice to be able to do this correctly.

Figure 2: Nuclear imaging stress test results of patient. Various cross-sectional views of the heart. Yellow areas are the radioisotope. 



Another diagnostic procedure (as well as interventional procedure) I was able to observe was in the catheter lab (also known as the cathlab). Using catheters that are snaked through the femoral artery and into the heart, doctors are able to observe the coronary arteries that wrap around the heart through the use of contrast dyes that are released from the catheter, as shown in Figure 3 below (this diagnostic procedure is also known as a coronary angiogram). The two cases I observed both had moderate coronary artery occlusions and therefore the doctors went forward and placed coronary stents into the occluded areas to open the arteries up again. This procedure was all done through catheters as well.

Figure 3: Example of an angiogram taken from massgeneral website.

The last procedure and arguably the most interesting procedure I observed this week was in the electrophysiology testing lab. Patients that suffer from arrythmias often undergo electrophysiology testing to determine the exact cause of their arrythmias. Similar to the coronary angiogram/stent procedure, the electrophysiology procedure was done through catheters. Special catheters were placed into the heart that contained electrodes to pace the heart as well as measure the voltage potentials of the heart. Through a specific software, the doctors were able to 3D render an anatomically correct image of the patient's left ventricle using a catheter that had ultrasound and then go forward and map out the electric potential of the entire wall with a catheter that contains electrodes. The doctors also used catheters to send electric impulses into the heart tissue in order to try to induce the arrythmia and therefore pinpoint exactly where the arrythmia was occurring. After mapping out the electric potential, another catheter was placed into the heart to ablate (burn off) the areas of tissue that were the likely culprit of the arrythmia. Figure 4 shows an example of the 3D rendering as well as the electric potential map.

Figure 4: 3D rendering of patient's left ventricle and electric potential map.

Overall, this week has been really eye opening and am glad I was able to observe so many different procedures being performed within such a short time span. I look forward to next week when I meet with Dr. Gaudino and his fellow to establish a research project that I can do while I am here as well as hopefully observe some interesting heart surgeries. I have definitely already been immersed pretty deeply into the clinical setting and I look forward to being immersed even more.






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