Monday, October 5, 2015

Atrial Bleeping Fibrillation, Part I

The last three weeks of Ironman Arizona preparation have been of the "build" variety, meaning a whole ton of time and miles.  Week #2 was 22 hours, with 15 on the bike.  By the end of this third and most recent week, I was predictably feeling burnt.  This was not surprising. 

I recovered pretty quickly with a few days off, with the notable exception of my heartbeat still feeling slow and irregular, which it has for about a week.  I hadn't given it much thought other than it being PVCs/dropped beats, which is not much of a problem, but it occurred to me that it might be atrial fibrillation, which would be.  But atrial fibrillation usually correlates with a faster heart rate.  Yesterday morning, I ran before work--a slow, short, recovery style run.  It felt easy for the most part, but with periods of wanting to stop for no good reason.  When I got to work Saturday, I figured I'd put it to bed one way or another.  So I hooked myself up to one of the monitors in an empty OR:

It's slow, irregular, and lacking the "P" waves associated with a Normal Sinus Rhythm.  So I got myself seen in the ER while working, like a typical bad patient doctor would.  The official EKG showed the same thing: Atrial fibrillation.  As in, atrial bleeping fibrillation, as in, full stop on IMAZ prep and perhaps other things, as in, I'm likely to get cardioverted (shocked) in the next couple days and put on meds to anticoagulate and maintain rhythm.

Educational moment--In the diagram to the right, the EKG waveform for atrial fibrillation is shown on top.  The purple arrow on the lower tracing points to a "P" wave, which indicates normal atrial contraction.  There are no identifiable "P" waves in atrial fibrillation, and a corresponding loss of cardiac power with ineffective atrial contraction.

In hindsight, this was probably not the first episode I've had. When I ran my first marathon back in '99, a trail run near Santa Cruz, I remember feeling funny heartbeats towards the end of the race, and for awhile thereafter.  Soon after that, I remember getting on a treadmill with a heart rate meter (a novelty back then, as far as I remembered), and pushing my heart rate up to almost 190. This may not seem high to some, but currently, my threshold HR is in the mid to high 150s, and my "barf number" is in the low to mid 160s. Relative to the astronomical number I pushed at age 32, I thought my current HR must have been the aberration, a product of subsequent medical school and residency deconditioning or stress. More likely, the earlier, higher number was the anomaly.

I'm not sure where this is all leading, both in the short run and long.  The cardiac possibilities run from cardioversion (low voltage shock) and being basically done with it, to needing ongoing meds and even a catheter ablation procedure if it keeps coming back.  The lifestyle implications are that I need to get off my typical industrial doses of caffeine.  Crap.  I'm a big fan of caffeine.  But I'm a big fan of cardiac output too.  The endurance possibilities run from just having a long taper into IMAZ to having to become basically a recreational athlete.  This actually wouldn't be the end of the world.  But being a non-athlete is a non-option as far as I'm concerned.

I'm reading up and talking to people I know to make sure it's handled the best possible way.  Tonight I'm going to have a phone chat with Larry Creswell, Cardiac surgeon and endurance athlete.


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