Day 3 of Cardiology - Sean

This morning in the Cath Lab, there was a patient that required Cardiac Resynchronization Therapy (CRT). According to Dr. Hsu, this was one of the more complex procedures in the Cardiology specialty. The patient currently had a pacemaker implanted but the rate of contraction it was programmed for before no longer was effective in orchestrating a synchronized contraction for efficient blood output. 0.08 seconds was the interval that the patient's current pacemaker was off. Thus, the CRT would serve as an upgrade replacement for the current pacemaker.

The heart beating with the patients old pacemaker, under flouroscopy.

During the procedure when the old pacemaker was removed, an external pacemaker was used while the new electrodes were put into place. The cardiologists decided it was better to leave the old electrodes in place since they were so embedded into the heart's tissue. It would do more harm than good to surgically remove them.

The new pacemaker required the placement of 3 new electrodes: one that leads into the right atrium, one that leads to the lateral wall of the left ventricle through the coronary sinus, and one that leads to the right ventricle near the interventricular septum. Each target was carefully selected by the cardiologists for maximal desired effect.













Here the 3 new electrodes are visible; the 2 old electrodes are present as well.














The new pacemaker by Medtronic; it was implanted in the left subclavicular region.

An interesting thing I learned was that whenever a pacemaker procedure is performed, the manufacturing company of the pacemaker sends representatives to bring the device to the operation and also assist during. I was told that Medtronic is the largest pacemaker company, so their representatives were in the flouroscopy room during the entire procedure. One good thing about this was that after the 5 hour procedure, the representatives treated us all out for lunch.

In the afternoon, I went to the echocardiography room where Dr. Wang explained all the tricks about reading the ultrasound images. The premise is similar to venous ultrasound, except you're looking at the heart. Doppler is again useful here to detect blood flow, so anytime you see both colors crossing at the valve regions, that is indication of regurgitation. The velocity of the blood flow could also indicate stenosis if it was higher than normal. I was surprised when Dr. Wang performed transesophageal echocariography because I did not realize that the probe would be so long. Lidocaine spray was used to numb the gag reflex somewhat, and it looked very uncomfortable for the patient, but the back view of the heart seemed very useful for locating any problems in that region.

I was sort of pimped once today, but I guessed right:
Dr. Wang -- "Is this a thrombus?"
Me -- "Where?"
Dr. Wang -- "Right here." (points at screen).
Me -- "Oh. That looks like its the left auricle."
Dr. Wang -- "Good. So what do you think?"
Me -- "Umm...it doesn't look like a thrombus to me, but I've never really seen a thrombus before."
Dr. Wang -- "Sometimes you need to have some guts and confidence in your answer."
Me -- "Hmm. No, that is NOT a thrombus."
Dr. Wang -- "Very nice!" (chuckles a bit)