Supraventricular tachycardia (SVT)?

rdt

I had what I think may have been some cardiac arrhythmia today while on a ride.

I had just completed a maximal effort up a very steep climb, roughly a couple of hours into a hard ride. I'd been riding strongly and felt very good. At the top of the climb I had a very quick p!ss stop, and on getting back on the bike saw the HRM was reading a very high reading (around my normal max).

I thought it may have been interference from others, so started riding on my own to rule that out, and riding very gently compared to previously. My HR remained very high (170s - 215), and seemed to be proportional to the effort I was putting in. Compared to before the stop, it felt like I'd lost about 1/3 - 1/2 of my power. I didn't feel palpitations, but I felt a bit "fluttery".

This lasted for about 10-15 minutes. Then, my HR suddenly returned to the level that I'd expect for the effort I was expending, full power returned, and was able to very easily ride away from the guy I'd been struggling to keep up with for the past 5 minutes. I was then back in the groove for the next couple of hours without a problem.

This wasn't some normal "warming up" experience after a stop - the stop was very quick, and the symptoms I experienced were very different. I suspect it may have been some sort of arrhythmia, possibly adrenaline related, as a result of hammering it up the earlier climb chasing down some other riders.

I plan to call the quack tomorrow (however, I expect they'll say something like "don't ride so hard" or "here's a sackful of beta-blockers", neither of which I'm likely to follow unless in extremis...). I remember reading a similar anecdote on bikeradar in the past few years, but can't find it via a search to see how that thread went.

Does anyone who knows about such things have any input for me? Cheers.

I am the god of hell fire

Impossible to diagnose online Id have thought

Although it doesnt sound like an arrhythmia to me - not that Im an expert
Plus Id question exactly how accurate a cycling heart rate belt is too

Go see a quack
ASAP if it happens again

Bozman

Your doc will let you know but if it is something like AF(artrial fibrilation), i get it from time to time and a major contributing factor is dehydration, the doc told me to drink 3 litres a day and to avoid a night on the booze followed by a day on the bike.

rdt

I've had spurious readings from HRMs before so appreciate that's not evidence in it's own right. It was the combination of factors (HRM, fluttering feeling and big loss of power) that gave weight to my concern, together with the fact they all disappeared simultaneously.

I was well hydrated, and had had no booze last night and little during the week - I did a big/hilly ride on Wednesday and had been in rest & recovery mode since then.

I'll go see the quack and see if they have much to so say - though I'm doubtful.

piquet

[quote="rdt"

Does anyone who knows about such things have any input for me? Cheers.[/quote]

sounds very similar to my recent experiences using my new Garmin 800 - and lots of other folks too. HR suddenly spiking to 220 or so. Turns out there is an issue with the new garmin HRM soft strap - but it was scary the first time it happened.

My problem appears to have resolved (2 rides only) buy replacing the strap with a polar alternative

rdt

Piquet wrote:

sounds very similar to my recent experiences using my new Garmin 800 - and lots of other folks too. HR suddenly spiking to 220 or so. Turns out there is an issue with the new garmin HRM soft strap - but it was scary the first time it happened.

My problem appears to have resolved (2 rides only) buy replacing the strap with a polar alternative

It doesn't sound much like your Garmin issue, as my experience was accompanied by two physical symptoms as I've explained!

MarcBC

As a previously very fit man who survived a heart attack and with atrial fibrillation / tachycardia now in my life GO SEE THE DOCTOR.

It will turn out to be nothing but it is not worth trying to find an answer on here just to placate yourself.

I take tablets to control it so life continues albeit with careful watch on my heart zones. The general premise being that arrhythmia begats arrhythmia i.e. the more it happens the more it will happen. Not worth the risk.

ut_och_cykla

I suffer from occaisional slight arythmia - which has been medically checked out and put down to the normal variation in people's heartbeat - but I was told that if it got to a point where it made me feel 'strange' faint etc i should see a doc straight away. So if you are in anyway concerned - get yourself checked.....

Brommers76

Try and find your pulse next time at the wrist or jugular. If you cannot count it after a toilet stop then the HR reading is probably correct and you may have a problem. If you are sure you had symptoms that are not explainable by stopping and getting off the bike after a max effort then I would get yourself checked out anyway.

If you are concerned enought to raise it on a forum with strangers then I would say get yourself to the doctors.

MarcBC

!! Perhaps I am over reacting but, I still think it should be looked at without question:

http://www.bbc.co.uk/news/uk-england-ma ... r-13699084

dilemna

Bozman wrote:

Your doc will let you know but if it is something like AF(artrial fibrilation), i get it from time to time and a major contributing factor is dehydration, the doc told me to drink 3 litres a day and to avoid a night on the booze followed by a day on the bike.

Sure this wasn't your gf or Mrs Bozman?

dilemna

rdt wrote:

Piquet wrote:

sounds very similar to my recent experiences using my new Garmin 800 - and lots of other folks too. HR suddenly spiking to 220 or so. Turns out there is an issue with the new garmin HRM soft strap - but it was scary the first time it happened.

My problem appears to have resolved (2 rides only) buy replacing the strap with a polar alternative

It doesn't sound much like your Garmin issue, as my experience was accompanied by two physical symptoms as I've explained!

Everyone experiences tachycardia or arrythmia at one time or another, where one's heart beats excessively fast typically when at rest. Yes it is extremely worrying at the time but it should only last a couple of minutes, if this long. If yours lasted 15 minutes as you state then you really should be dead. On-line diagnosis is fraught with difficulty. I would suggest you visit your doc. Dehyrdation or an irregular heart beat might have been one of the causes. What's your resting pulse rate - 30?

rdt

Initial thought from the quack is supra-ventricular tachycardia (SVT):-

http://www.patient.co.uk/health/Suprave ... SVT%29.htm

I'm off for an initial ECG, and may need to wear a portable ECG for 24hrs or 7 days, depending on what the initial finding is.

rdt

dilemna wrote:

Everyone experiences tachycardia or arrythmia at one time or another, where one's heart beats excessively fast typically when at rest. Yes it is extremely worrying at the time but it should only last a couple of minutes, if this long. If yours lasted 15 minutes as you state then you really should be dead. On-line diagnosis is fraught with difficulty. I would suggest you visit your doc. Dehyrdation or an irregular heart beat might have been one of the causes. What's your resting pulse rate - 30?

According to the quack, and from what I've read, in some cases they can last up to several hours, so your bolded bit is not correct.

From I've been told, because the heart isn't pumping correctly during SVT, it leads to a drop in blood pressure and thus feelings of lethargy, which in extreme could lead to collapse. The impact on me was pretty mild, as I was still cycling (including uphill), it just felt much harder than it had prior to that point - it felt like I had 100+ hard miles in my legs instead of 25.

I was well hydrated. Resting pulse is roughly mid 40s.

Brommers76

Friend had that (more runner than cyclist). He did go light headed and it also seemed very random (sometimes on a long run, rarely when racing, sometimes when doing rep work etc). Fixed with an ablation which was a few hours in hospital then running within 3 days and no symptoms again.

Hope you pin it down and you can get it fixed easy.

the_jackalcp

You need to be careful if you have another attack as carrying on with exercise is really not a good idea. As you have pointed out SVT (although you should really have been told that you suffered a narrow complex tachycardia) causes a drop in blood pressure. This leads to decreased oxygen availability for all your muscles, heart included. Add exercise on top of that and you are simply compounding matters.

If it happens again you need to stop as soon as possible, sit down and do your best to relax. Concentrate on your breathing, slow deep breaths are best. Talk to your doctor about valsava's maneuvers, or look it up online. They can help but could make you feel worse.

Realistically your ECG is unlikely to show anything as your attack is paroxysmal, ie sudden start and finish. Unless you have an episode during the ECG or 24hr/7day tape then there will be nothing to see apart a sinus rythmn.

rdt

The Jackalcp wrote:

You need to be careful if you have another attack as carrying on with exercise is really not a good idea. As you have pointed out SVT (although you should really have been told that you suffered a narrow complex tachycardia) causes a drop in blood pressure. This leads to decreased oxygen availability for all your muscles, heart included. Add exercise on top of that and you are simply compounding matters.

If it happens again you need to stop as soon as possible, sit down and do your best to relax. Concentrate on your breathing, slow deep breaths are best. Talk to your doctor about valsava's maneuvers, or look it up online. They can help but could make you feel worse.

It's only recently that I've begun using an HRM again. I think without that, I wouldn't have identified what was going on, as the symptoms seemed mild - I'd have just thought I was tired for a period, which then strangely passed.

I think I may already use a valsava's manoeuvre to stop hiccups. So I'll try this if I have another incident.

The Jackalcp wrote:

Realistically your ECG is unlikely to show anything as your attack is paroxysmal, ie sudden start and finish. Unless you have an episode during the ECG or 24hr/7day tape then there will be nothing to see apart a sinus rythmn.

That's what I guessed. If so, is that the end of the diagnosis road? In the example that Brommers76 mentions above, in order to have undergone that sort of treatment, is his friend's condition likely to have been much more frequently occurring / more serious and have been ECG'd to confirm it?

Thanks for the input.

the_jackalcp

You may get an exercise stress test where they try to purposely cause the arrhythmia or at least see if exercise does. I can't believe you will have an ablation or other op unless they find an accessory pathway that is causing the tachycardia and the first step towards that will be ecg evidence.

roddixon

That's what I guessed. If so, is that the end of the diagnosis road? In the example that Brommers76 mentions above, in order to have undergone that sort of treatment, is his friend's condition likely to have been much more frequently occurring / more serious and have been ECG'd to confirm it?

Have the ECG and 24h tape done, if that is normal then you may be advised to wait until it happens again and get down to the GP to get an ECG documented at the time of that episode. You may be offered a heart echo to rule out any structural defects that may be the cause of the "supposed" arrythmia.

If you do go on to have more episodes then you may also be offered an EPS (electro physiologial study) of the heart nerve structure, to identify the root cause and treat with an ablation. This procedure has a risk of stroke in the order of 1 in 200.

Your episode was self-limiting and hopefully won't happen again. If you are otherwise fit, I would wait and see if it happens again and get it documented.

All the best, Rod (had AF twice, both times longer than 24hrs, I didnt have an ablation and havent had an episode for 6 years now. Oh and I'm an anaesthetist so know (at least partly) what I'm on about )

p.s. yes, before having an ablation a definate diagnosis is required i.e. ECG documentation.

rdt

Thanks for the info, Rod.

roddixon

dilemna wrote:

Everyone experiences tachycardia or arrythmia at one time or another, where one's heart beats excessively fast typically when at rest. Yes it is extremely worrying at the time but it should only last a couple of minutes, if this long. If yours lasted 15 minutes as you state then you really should be dead. On-line diagnosis is fraught with difficulty. I would suggest you visit your doc. Dehyrdation or an irregular heart beat might have been one of the causes. What's your resting pulse rate - 30?

Sorry but not everyone, extra beats or ectopics are frequently seen in otherwise healthy people, even athletes, but arrythmias at rest lasting more than a few seconds are not "normal".

I must be double dead then, and some elderly people just don't know when to stop dying from their persistent AF, years of persistent arrythmia sometimes. :roll:

roddixon

rdt wrote:

Thanks for the info, Rod.

No problem, feel free to PM me if you have any more questions.