In March of 2008 I began treatment for a potentially fatal heart arrhythmia whose cause was unknown. I was fit and healthy, having spent a good part of my adult life as an elite cyclist, much of it racing in Europe.
After 5 years of fence-sitting on the part of my doctors, I have been given a diagnosis of ARVD/C (Arrhythmogenic Right Ventricular Dysplasia / Cardiomyopathy). I lack the known genetic markers for the disease as well as some of the structural changes that accompany ARVD/C, and my condition has shown no indication of being progressive (yet).
There is a growing population of current and former endurance athletes who end up with acquired arrhythmias, and a diagnosis of ARVD/C. But by placing these athletes in the ARVD/C patient population, we are potentially ignoring the very real likelihood of an acquired condition, similar, but different, from ARVD/C.
This blog is written as a resource for athletes with acquired arrhythmias, as well as anyone about to undergo endo or epi-cardial ablation, or the implantation of a ICD. It is also written to help generate some critical mass of interest in support of further research into acquired arrhythmias in endurance athletes and others. Feel free to contact me through the comments page if you have any questions or wish to make a written contribution to this blog.

Saturday, February 28, 2009

Stress Test Success

(non sequitur wombat)

Extreme Cardiac Rehab began not-so-Extremely. Day One I plodded along on a half-hour “run” at a sad pace just shy of eleven-minutes-a-mile. Keeping the heart rate below 150 was not difficult, the ticker wouldn’t tick much above 140 without feeling over-done. I was still taking beta-blockers, and still feeling the odd PVC, especially while running. The PVCs at-effort were much calmer than PVCs prior to the ablation, they never felt like my heart was in my throat. But they were still present and somewhat disconcerting.

In less than a week, though, I was running at sub-ten-minutes and every day was an improvement. On the bike I confined myself to an hour out and back on the local canal towpath. The extra resistance of the dirt towpath kept the effort steady. Often, when bike riding, a graph of cardiac output resembles a mountain range, mainly because of variations in terrain and the constant slowing down and speeding up required while riding in traffic. Where running is smooth and steady, generally confined to a ten-beat differential, riding is up and down, it is easy to fall below 100bpm on downhills, as high as you care to go on uphills. On the flat, dirt towpath, I was able to keep the heart rate stable, aiming for 130-140bpm.

Over this six week period I ran 38 miles and rode 611 miles. I never had any V-Tach, and the PVCs seemed to diminish over time, though they never went away completely. Usually the first 20 minutes were the worst, but as I warmed up the PVCs disappeared. Once, on a rare weekend two-hour ride, my heart rate monitor flipped out and shot up to 180bpm briefly at a point when I was not doing more than 130bpm. That night I “carelinked” my ICD just to be sure that this anomaly was in fact a heart rate monitor malfunction. It was. The ICD picked up no V-tach, and no unusually high heart rate.

December 17th I was back in the basement stress-test lab of the University of Pennsylvania, wired to the EKG, belting out the treadmill. The test was 100% smooth. I had individual PVCs and the occasional couplet (two PVCs back to back) about once or twice every 120 to 150 beats. Which, while not perfect, was still a far improvement over my last test . I ran to 17 minutes, the last three minutes were between 170 and 175bpm. I wanted to reach a heart rate I knew I’d need to be at if ever I returned to competition, and 175 is about my threshold.

Looking back, and looking forward, it is unclear to me what, precisely, causes these PVCs. Even now, three months after the last ablation, I have them. “Clinically” they are inconsequential, meaning that unless they increase markedly I really shouldn’t worry about them. But it is interesting to me what they mean, and why they happen. I am overjoyed that I have almost zero PVCs unless I’m exercising. That is a giant improvement.

There is also a level of “pericardial noise” –for lack of a better term. By this I mean a sensation of weight, sometimes slight discomfort, in the chest. It’s never painful and has never made me stop what I’m doing, but it seems to be present when I exercise. I notice it in the beginning, by the end of a workout it’s usually gone.

The stress test was followed by a “Non-invasive Programmed Stimulation” Test (NIPS) during which I was knocked out, and run through the gears. The docs paced my heart up to high speed using my implanted defibrillator and injected adrenalin. The goal was to see whether I could be artificially induced into V-tach. I was uninducable.
Sent home with a clean bill of health, and no more prescriptions for drugs, I was given the “all clear” to exercise to my heart’s content. But there was one last, small, worry hanging over my head: genetic testing for ARVD / C.

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