Week Three was by far my most interesting week during immersion yet. I spent most of my time in the cardiac electrophysiology service within cardiology. This service is basically a cardiac catheterization lab, but instead of fixing 'plumbing' problems of the heart as they do in angio-cath, they fix the 'electrical' problems of the heart. In most of the procedures I viewed, the doctors start by placing catheters into the patients heart through a vein near the abdomen/leg. The first catheters they send into the heart, are mainly to take electrical and pressure measurements that help to guide the rest of the procedure. They then insert a catheter that has an ultrasound transducer in the tip. They use this to make a shell of the anatomy of the heart they are trying to fix. If this anatomy is on the left side of the heart, they pierce the septum with a small needle in the catheter to get the transducer over to the left atrium and ventricle. Once the part of the heart causing the electrical problem is found, they then use RF frequencies produced by a different catheter, to ablate the tissue.
In patients with atrial fibrillation, the fib is most commonly caused by the electrical signals from the pulmonary veins. It is common in the ablation procedure for A-Fib to ablate around the veins to disconnect them electrically from the heart. To do this, the doctors sometimes use 3d MR or CT reconstructions of the heart to guide the procedure and show exactly where the veins are.
In addition to ablations I also got to view a pacemaker implantation. While this procedure was more involved than ablations (i.e. the fact they actually have to cut into the patient and place the leads and generator) it was a lot shorter.
This upcoming week I plan to continue in cardiology and hopefully view the angio-cath lab to get a full understanding of cardiac cath procedures.