Racing with a Pacemaker, the early years

Last July (2024), I got a dual valve Biotronik pacemaker. I had thought I could avoid further interventions after the ablation, but the electrophysiologist I saw for a second opinion (really a fourth opinion, counting the Lubbock EP, my Community Health EP, and the friend of a friend I spoke with) was the first cardiologist who told me that without pacing, I wouldn’t be able to get my heart rate up into the range I would want it to be to continue running, training, and racing. That sold me!

I asked the device rep who was setting up the algorithm after my surgery if someone could kill me if they hacked the system the way that they kill the Vice President in Season Two of Homeland. He did not think that was really possible. So hey, good news.

First Half Back

During Fall training, I did have some moments where I felt some palpitations, and I learned that I had a brief Afib episode in September, but the doctor wasn’t worried about it. Last December, I ran the Annapolis Half Marathon. I trained all Fall and I was enthusiastic about being back running a race, but I didn’t feel like I was really racing. The terrain was hilly, I never really felt like I was approaching my old form. But it was good to be out there. My nieces came to cheer me on. I finished in 2:04:12, 9:29 pace. That was the slowest half marathon I had ever run, but I could see the way back. I was willing to be patient.

Indianapolis Mini 2025

On Saturday, I ran in the Indy Mini-Marathon. The Mini is a half. The state of Indiana has really done itself wrong by naming this race the Mini because now everyone in the state thinks that a half-marathon is universally considered a mini-marathon, a term I had never heard before moving to Indiana. Yesterday, in the device clinic, the company rep was talking to another company rep on the phone and he said, she ran a mini, as if the company rep who was not in Indiana would also know what that meant.

I have had a tremendous training block. As my coach said when we talked about my race plan, “you are crushing it.” I did a fifteen miler two weeks before the race at around 9 and a half pace. I did a hard 1600 x 800 x 800 x 1600 workout at decreasing paces with a quarter mile recovery and then half mile recovery before the last mile — the first mile was 7:30 – then the 800s were around 7:20 and the last mile was 7:03. I was jazzed. My heart rate got up to 140 and stayed there pretty consistently through the whole workout.

When I talked to my coach about my race plan, I thought I was in PR shape. My half PR is 1:42:54 and I thought maybe I had that in me. My coach was a bit more conservative. She said, you’d have to have a broken leg not to finish under 2 hours, and then she suggested 1:50. I talked her down to 1:45. My plan was to start in the 8:20s and end in the 7:40s. I was a little nervous about it, but I felt strong and fit.

My coach suggested I do some things that were new to me — finish eating and drinking two hours before the race started. I’m not sure I’ll do that next time. It did mean I didn’t feel like I had to pee at the start line, but I am used to drinking a lot of fluids up until pretty close to start. I took a gel right before we started, which maybe was against recommendation, but I wanted to have the energy. It was cool — 55 degrees Fahrenheit — and a little drizzly to start; it was no excuses weather as they say. Alas, I ended up having excuses.

At first, I felt pretty good. I eased into it, starting at 8:27 and making my way down to 8:01 at mile 6. Maybe a little before the mile 6 marker, I was running alongside and then in front of two dudes who were having a shockingly anti-Semitic conversation. Maybe I shouldn’t be shocked anymore. They said some vague conspiracy things that I thought I could ignore. Then they said, “Jews have destroyed every civilization they have been a part of.” To that, I turned and said, “Oh my god, that’s some fascist shit, you should cut it out.” Then I pushed to run a little faster to get away from then. I really don’t think that made a difference. My heart rate chart doesn’t seem to show a difference. But I think the expenditure of energy did have an effect. You start to go into the Speedway, where the Indy 500 is run, just a little bit before the 6 mile marker. You go down a steep decline and then up an incline and then hit 6 coming in. Maybe that felt hard too? I started to feel like this is hard, almost out of nowhere. Mile 7 was 8:19. Mile 8 started getting harder. It was 9:13. During the 9th mile, I started to feel some chest palpitations and tightness, and I walked for about 20 seconds. After that, I would run a little and then walk when my chest started to feel tight. I was so frustrated and I started to wonder if my mental game was off. Should I just be pushing through this tightness? Am I wussing out? The last five miles were in the tens. I saw my husband at mile 12 and I stopped and hugged him and burst into tears, saying, “I’m having a really hard race.” He said, I know, keep going. I finished in 2:01:07. That’s a 9:14 pace.

I was so frustrated with myself. How had I been so wrong about my fitness? We went to brunch and I started to look at my heart rate and pace charts from my Garmin. They were kinda weird. My heart rate, it turns out, started falling 8 minutes before my pace fell off in mile 8. That made me start to wonder if my pacemaker had failed me. My pacemaker sets a floor of 60 when I am at rest and it pushes me into a higher aerobic zone as I am more active. I used to run at around 115, and it pushes me up to 130-140 and higher as I need it. But while my pace really started falling off at 58 minutes, my heart rate fell off noticeably at 49 minutes. It came back up briefly two minutes later and then fell and never came over 120 the rest of the race. Now I began to wonder if I had an equipment malfunction. I called the device clinic. They said, yes, that looks like an equipment fail, come into the clinic tomorrow and we will have a company rep help you.

So I met with the Biotronik representative and he told me that the Biotronik uses two approaches to assist with activity: the Closed Loop Simulation (CLS) algorithm or an accelerator. The CLS algorithm is supposed to respond to activity, but it can fail to perceive during activity that you need continued support. From the brochure linked above:

Changes in the intracardiac
impedance are a direct result of
increased or decreased contractility
and therefore provide the basis for
true physiological rate modulation
with Closed Loop Stimulation.

As I understand it, intracardiac impedence is the electrical resistance that the heart experiences. So more resistance suggests more work. In any case, it appears that the pacemaker did not see that I needed more support, so it dropped off. This can happen. They can either make the pacemaker more sensitive — which is what they did for me — or they can change it away from the CLS algorithm to the accelerator before a race. The benefit of changing to the accelerator is that it would just increase as I moved and so as long as I needed the support I would get it. The downside is that it wouldn’t help with anxiety or feeling ill. Now I do wonder if I have enough upper end capacity to manage the anxiety and illness so that it would be ok, but the Biotronik rep thought that it was better if possible to stay with the CLS algorithm. It takes a couple weeks to adapt, so if I really want to know if it works, he suggested I go run a hard 7 miles and see what happens. If it adapts, I am in good shape, if in the eighth mile, it falls, I might need to switch to the accelerator.

But at least for now, I feel like I have a path forward. I am calling this post “the early years” with the hope of many more well-adapted and algorithmized years of racing and running. The whole promise of the pacemaker is that it would be what would give me the support while I ran. I’m still hoping that it does and that I’m not being naive with this hope and expectation. I’m not sure how long I can be patient!