biking with a pm

So I am looking for any advice or even opinion on what might be going on with my pm while biking.
First of all I have a Boston Scientific blended pacemaker that is currently set on minute ventilation only, I am paced 100% of the time and am a runner as well as a biker. I have had it for 2 months.
Running is great, feels like normal and is getting better and better but biking is another story altogether. As an example I just finished a 70 mile road bike ride, the first 20 miles were fine, no problems than the next 20 miles I felt out of breath and my heart rate seemed out of sync, then that settled down and the rest of the ride was better but I still had bouts of high heart rate that would quickly settled down.
I wonder why the pm works fine for running but is just not right on the biking side.
Any insight is appreciated.

Tim

11 Comments

Only thing I heard

by Theknotguy - 2014-11-09 08:11:44

Only thing I've heard so far is that some PM's (like my Medtronics) don't react well to biking because the torso isn't moving and the accelerometer doesn't get activated. It doesn't sense your movement so doesn't bump up your heart rate.

I don't bike so I can't give you any personal insights.

Others should chime in here fairly soon and give you a better answer.

Minute ventilation sensor

by golden_snitch - 2014-11-10 01:11:42

Hi Tim!

As the motion sensor alone has its limitations, the minute ventilation sensor alone has them, too. It's a sensor that reacts slowly. If you combine it with a motion sensor, you have the motion sensor for the quick response, and the minute ventilation sensor for the "endurance" performance.
So, if a pacemaker features this combination, I'd always have both sensors activated. They do their best job in combination.

I had this sensor mix, too (from Sorin, not Boston), and was forced to run around with motion sensor only for a while. It was a catastrophe, and I finally came to the conclusion that, together the sensors worked great, but they were not made to work well alone.

If I were you, I'd have both sensors activated, fine tuned, and then see, if that's better than minute ventilation only.

Inga

P.S. Where are you paced 100% of the time?

SENSORS

by DJDIV - 2014-11-10 01:11:47

You probably need to experiment with adjusting your sensor options. You are the best person to relay to the physician the facts. I assume you have a number of options with your pacemaker so take one at a time and see how you do. My take focus on Activity Response and Activity Threshold settings.

Minute ventilation

by advracer - 2014-11-10 06:11:08

Thank you Inga!

I am paced in the atrium all the time. I also had a motion based sensor and like you it was a total disaster, replaced it after a year with the blended sensor because when I was running all it did was give me a constant high heart rate, up the hill and down the hill so I am concerned about having the motion sensor turned on because I think it might ruin my running ability all over again.

Tim

Sensor combination

by golden_snitch - 2014-11-10 07:11:23

Hi Tim!

If you want something better than a motion sensor alone, you get the combination that you have now. Both sensors have their limitations, but together they kind of work hand in hand, one making up for the shortcomings of the other. So, getting the Boston Scientific pacemaker with this sensor combination, but not turning both sensors on, does not really make much sense.

In my old Sorin Reply DR pacemaker one sensor was leading, when both were switched on, and this was the minute ventilation sensor. I'd expect that Boston Scientific's combination works the same way. Also, in my Sorin there was a cross-check between the two sensors. So, I'd not worry that the motion sensor messes it all up.

If you want to read about someone who is doing extremely well with your type of pacemaker, google: Heidi Dohse. She's cycling a lot. Has both sensors switched on, had them fine tuned, and is now competing in lots of bike races, and I think she mountainbikes, too.

Inga

Sorin info

by golden_snitch - 2014-11-10 08:11:51

Here's some information from Sorin on their blended sensor, and as I said, I'd expect the Boston Scientific version to work similarly:

Accelerometer (G): Provides fast response at beginning of exercise and indicates end of exercise.

Minute ventilation (MV): Offers a physiological and gradual response to exercise, detects increased metabolic need and adapts pacing rate in proportion to exercise.

Blended-Sensor Operation:
During dual sensor operation, the minute ventilation sensor is dominant and solely determines the rate response when both sensors detect exercise.

Cross-checking of both sensors:
The sensors continually cross check each other at
the beginning and end of exercise. Rate response will continue only if both sensors simultaneously detect activity. The combination of two sensors also prevents rate increases due to artifacts. Any increase not confirmed by the second sensor results in a return to the basic escape rate.

Inga

Blended

by advracer - 2014-11-10 09:11:49

Thanks Inga! This is very helpful but I wonder if the programming is that much more difficult with the blending.
It's already been difficult enough with just trying to get the mv to work. Was it difficult to get your pm adjusted initially?

Tim

Fine tuning

by golden_snitch - 2014-11-10 10:11:37

Hey Tim,

oh yes, fine tuning can take a while! I think others here would subscribe that. In my old Medtronic Kappa, that I got back in 1999, I had your sensor combination, too, and if I remember correctly, it took nearly a year to get settings right. It was a bit easier with the Sorin device as it does not offer many rate response settings that you can actually tweak. I have heard that the Boston Scientific can be tricky, because for each sensor you have several settings that can be adjusted.

I no longer have the Sorin; the minute ventilation sensor quit its job when I was switched to epicardial pacing (MV sensors don't work with that), and the Sorin accelerometer alone was a desaster. My current pacemaker is a Biotronik Evia with a sensor called "closed loop stimulation" (CLS). Works pretty well for me so far, though the response changes a lot. What I miss with this sensor is that, after learning for a while it does not settle on certain settings, but keeps adjusting all the time. And it's not always a further improvement, but rather: two steps forward, one step back, one sideways, one forward, and so on. Sometimes this really gets on my nervs, but overall the CLS sensor is a huge improvement as compared to accelerometer only.

Hope you get the adjustments that you need, and will soon do much better when you bike!

Inga

A lot of ignorance about dual sensors

by IAN MC - 2014-11-10 11:11:05

As a runner/cyclist I have found the comments above to be extremely interesting and have just watched a video about Heidi Dohse which is inspirational !

Having already decided to switch to a dual sensor model from Boston Scientific at my next PM change I floated the idea with my PM tech ( who I had always thought was knowledgeable ! ) . He was arguing with me that you have either the accelerometer OR the minute ventilation switched on but not both together. He is obviously wrong as this simply doesn't make sense !

Tim asked the very apt question if the programming is likely to be more difficult with the blended sensors .. it makes me dread the battles ahead and I do wonder if this particular technician will be good enough; only time will tell !

Ian

accelerometer

by advracer - 2014-11-10 11:11:27

My trepidation with adding the accelerometer back into the mix is that my prior pm was accelerometer only and it was simply terrible for running. But if as Inga says the accelerometer is working secondary to the minute ventilation then it might be ok.
I am going to explore this with my tech here at Emory because biking is the problem now, running is great with MV only.

Tim

Pacer tech

by golden_snitch - 2014-11-10 11:11:54

Hey Ian,

I'd certainly question that PM tech's competence, if he does not know how a blended sensor works. Duh! In both, the Sorin device and the Boston Scientific, the two sensors can be combined = blended sensor. He should do a Google search, and get some reading done!

In the Sorin device you do not need to do a lot of the fine tuning as the rate response works with three settings only: Sensor choice (G, MV+G, MV), rate response mode (learn, automatic, fixed, off), and physical exercise (very low, low, medium, high, very high). So, there is not really much to tweak. But it still works really well. In the Boston Scientific it's a bit more complicated, I think. But I'm not familiar with that device, just checked the manual and it explains several different parameters for each sensor. So, I guess you can spend quite some time tweaking both, so that they work perfectly together in the end.

Inga

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