Pete1wray

A year ago I had a post-ride cardiac arrest. Luckily friends did CPR until my heart could be restarted with a defibrillator. Long story short, I ended up with an ICD implant in my chest. An ICD is a combination pacemaker/defibrillator. The pacemaker side of it controls my heart electrical signals and the defibrillator side is there to fire in case the pacemaker side loses control and then zaps my heart. The implant is made by Boston Scientific. So...the unit can be programmed to creat min/max heart rates, speed of electrical signals thru my heart and a lot of other things I guess I wouldn’t understand unless I was a cardiologist. However getting tall the settings right so that I can return to my old power and speed is proving to be a challenge. If it is set to be too sensitive I get a massive shock. Other settings seem to affect warmup time, acceleration and average power The unit can be reprogrammed relatively easily in a doctors office using a Bluetooth-like method, but the cardiologist and a Bos-Sci engineer say that cycling is too “smooth” for the unit and it’s accelerometers to function at optimal levels (I.e., it works better for runners). I am wondering if any others in the forum have pacemakers or ICDs and what their experience has been.

Iride01

I didn't want to be the first to answer, but it looks like I'm the only one.

I do have a ICD. Just a monitor. It was put in last October. I think the only reason was because I have good insurance. A couple months prior to that I'd been on a external cardiac monitor for a few weeks. In the follow up vist the doctor told me I have a very healthy heart. When I told him I'd wrecked a month before and had amnesia for 15 minutes prior to the wreck and to a varying extent till in the hospital room, he thought a minute and then said I was getting an ICD.

My wife was there, so I wouldn't win any arguments against getting one. However it still has just shown that I have a very healthy heart.

It does annoy me some when I lay on my side or try to scrunch up in tight places with my arms out front. Mine is about the size of a stubby pencil that you can't sharpen anymore.

Oh... and it hurts like heck when you get hit by a baseball in the chest or get in the way of an elbow.

Pete1wray

Thanks for your reply. I guess there aren’t many if us that have this problem. My ICD is about the size of a pack of cigarettes and about half as thick. It can be damn uncomfortable when I wear a seatbelt or try to sleep on my left side. One corner is particularly close to the top of my skin and sometimes it gets rubbed and chaffed by my clothing.

Iride01

So what do the cardiologist's tell you as far as cycling is concerned? If I'm not being too nosy.

Can you pretty much just go out and ride for as long and as hard as you feel able? Or do you absolutely have to stay below a certain HR level or Zone?

I don't have any restrictions from my cardiologist. So I many times will ride as hard as I can for several hours. Even when I'm going easy, I'm in LTHR Zone three and four for much of my riding time.

The doctors are trying to investigate a few times that I passed out over the years. However all those times were when I was not doing anything at all. Several incidents were when I was in very intense pain from cramps in what felt like every muscle group of both legs, feet and toes.

The cramping was not related to riding and was shortly before bedtime after a day of doing nothing. A medicine I had been prescribed recently was the cause of the severe cramps. Needless to say, I won't take that every again. Years before and after, I still have had some syncope incidents, but all when relaxed not doing anything other than having some episodes of various intense pain.

Personally I don't think I'm seeing the right doctors yet. None I've been to so far can find anything unhealthy about me.

zachdebeer6@gma

Hi, I'm also interested in this topic. I'm 65 and have been a keen long distance runner and cyclist (both road and trail for both) for over 25 years. I'm also a doctor, though not a cardiologist. A month ago I was fitted with an ICD (Medtronic) because I developed some dangerous rhythms, mainly ventricular tachycardia. I've also been put on a beta blocker to suppress the arrhythmia but it also has the effect of slowing the heart. I've been gently working my way back to running and cycling over the last 2 weeks, trying to get used to new rates and rhythms, and have found the running reasonably easy but when I'm climbing steeply on the bicycle I cannot always get my heart rate up as high as I would like/need. My assumption is that the accelerometer in the ICD, which detects movement and thereby increases heart rate, responds well to the movement of running but less so to cycling (exactly as you say Pete in your original post). It is even worse when I try cycling on a stationery bike, presumably because there is even less movement as the whole thing is basically nailed to the ground - I struggle to get my rate above 90! - whereas when I'm running, even gently, I can easily get up to 130. I'm going to discuss all this with my cardiologist (who is also a friend) when I next see him. There are all manner of different programs/modes/switches etc that can be chosen/adjusted in the ICD, but I suspect the main issue here is the accelerometer and how it is responding to different kinds of movement. Most people with ICDs are not keen runners or cyclists, so this is probably not a common issue!

Iride01

You hit the nail squarely on the head there. IMHO!

Darth Lefty 

I have an ICD. Actually on my second unit. I am not sure how yours is programmed but mine does basically nothing unless there's a really bad arrhythmia. I've got HCM, with arrhythmias and family history of sudden death... at least thankfully not afib that needs to be controlled. I have had no sense that the ICD is inhibiting my heart rate. I don't feel it pacing, anyhow, which is a very distinctive feeling. It basically leaves me alone unless something goes wrong. But I seldom ever leave zone 2. I'm very limited by my heart condition which causes angina (much less so since surgery).

I've never heard that they have accelerometers that adjust their settings for activity. I'll have to read up on that.

If you are taking medications like metoprolol consider that they are also inhibiting your heart rate.

Darth Lefty 

Boston Scientific has another sensor (marketed as RightRate) that measures respiration.

I get the sense this is for people who are paced most of the time. I've had techs tell me I'm on a <1% duty cycle

jims63

Hi everyone. I've had several Medtronics ICD's from 2002 after I survived a VT event following an MS Bike Ride. Also have a family history of sudden death. I've had a-fib episodes that have become more frequent this year and last night got zapped while on a ride after the ICD got confused between a-fib and v-tach. Over the years I've been shocked 3 times while on my bike and thankfully haven't crashed yet. In the beginning, it took the docs and techs a few tries until they got the ICD settings ironed out, but eventually they did. Don't give up if you are struggling with this and don't hesitate to ask them to bring in some help. It was another tech that eventually got mine figured out. I found this group while googling for some more info on cycling and ICD's. Figured I'm not the only one. Thank you all for sharing your experiences, it really helps! No need to stop cycling!

mriley

My experience was like Zach's (I shortened your handle.) I can't get my heart rate over 90 when riding on the road, which makes cycling difficult. After a 15 mile ride I always feel like I have strained something. This make me reluctant to continue. The pacemaker works very well for walking. (My running days are over.) I have a Medtronic micra. I suspect that, if the docs make the pacemaker more sensitive, then my heart rate would go too high when walking normally.

mschwett 

i have a st jude single chamber ICD implanted to control ventricular tachycardia due to a heart condition called ARVC, which is primarily (but not entirely) an exercise-induced condition that affects the heart's electrical pathways and thus rhythm. it's my second ICD, the first was implanted about 10 years ago and lasted 7 years.

i've been shocked maybe a dozen times over the years, but not for an actual VT event in several years, which makes me fairly confident in riding a road bike fast. i probably wouldn't ride a non-electric bike off road for any great distance where help wasn't relatively close. being shocked over and over again is NOT fun, even if it's (allegedly) saving your life.

i also take flecainide and bisoprolol, the result of which (plus a couple decades of avid swimming, water polo, running, etc) is that my heart rate is more or less impossible to get above 130. doesn't matter because i shouldn't be doing that kind of exercise anyway.

since my ICD is single chamber, it doesn't pace me. it has the accelerometer to help determine when a faster heart rhythm is sinus rhythm vs. a dangerous tachycardia, and it's rarely mistaken sinus tachy caused by exercising for the bad kind.

i second jims63 - the programming of these things is quite nuanced with regard to the various threshold, electrical levels, number of rounds of antitachy pacing and then shocks, etc. if you're not seeing an experienced electrophysiologist, find one!