Stress Test Success

(non sequitur wombat)


(Backwritten)
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.