Week 6: Electrifying

After weeks of waiting in anticipation, the parts for my project have arrived! Well, some of them at least. The triumph of the week was learning how to control the LEDs of my pulse oximeter sensor (see below) using an Arduino. The pulse ox works by shining light (alternating red and infrared) through one side of the finger and detecting how much passes through, via a photosensor on the other side. Absorption of light at these wavelengths differs significantly between blood loaded with oxygen and blood lacking oxygen, which conveniently allows me to calculate pulse rate. It has been close to five years since my last circuit design project, but I am really enjoying the learning/re-learning process. Plus, compared to my cells back in Ithaca, circuit elements are much more obedient and lower maintenance (in theory at least)!

It is fascinating how the same physics which govern how a circuit operates also govern conduction in the heart. A number of factors can cause a disruption in the normal electrical activity of the heart: electrolyte imbalance, congenital defects, too much caffeine. Luckily, there exists electrophysiological mapping technology to identify the exact location of short-circuits within the heart tissue. I watched a radiofrequency ablation (RFA) procedure where the doctor used the heat from high frequency alternating current to correct an arrhythmia. In some cases, the ablation can be performed using a laser or extreme cold (cryoablation). 

Another case that caught my attention was a patient who was having an exploratory catheter procedure to examine his failing heart. I overheard the doctor say: “This has mortality written all over my forehead.” This particular patient had a history of alcoholism, diabetes, was cirrhotic and had been in septic shock. Platelet count was 60 (low) and dropping. He had previously suffered a heart attack (STEMI- ST segment myocardial infarction) requiring PCI (percutaneous coronary intervention) and now the cath procedure revealed LAD disease, occlusion of the right coronary arteries, distal left main bifurcation disease and a left ventricle ejection fraction of 22% (>55% considered normal). Cardiothoracic surgery deemed an operation too dangerous. After many consults and some deliberation, the patient ended up back in the Cath Lab with Dr. Kim later in the week.

Two days later, I alternated between watching a brain tumor excision with Dr. Schwarz and the follow-up angioplasty procedure to salvage this patient’s heart. While Dr. Kim was prepared to stop after the insertion of the first stent, his colleague urged him to keep going. It ended up as a triple stent angioplasty (see picture taken from my notebook) which could not have gone much better! The brain surgery was also successful. While the procedures themselves are cool, it is amazing to step back and reflect on the implications of these successes, the precious time and quality of life restored to these individuals. 

If the week was not electrifying enough, Ashley and I had the opportunity to shadow the ER from the patient side. Poor Ashley was having heart palpitations, arrhythmias and chest pains which was NOT OK!  After 10 hours of mostly waiting, we left with Ashley feeling loads better and an EKG report showing some delta waves indicative of Wolf-Parkinson-White Syndrome, but nothing imminent. The follow-up cardiology appointments went really well and the arrhythmias, chest pains, even the delta waves disappeared!!?? Thank God Ashley is back to her peppy self and can go back to studying the heart as a researcher instead of worrying about her own!