Apple Watch ECG - SVT?

[Arrythmiaconfusion]

I have had both IST and SVT (short runs) caught on holters previously. Also had a bad case of myocarditis a few years ago that left scarring.

Recently my HR went above 160bpm, when I would have expected 100-120, and I may have had a longer run of SVT (attached). I was stressed and walking slightly upslope in the heat, but not far or fast. Not sure how quick it went to 160, but it did come down fairly slowly - 140 when I stopped, then 120 and 100/90.

Grateful to know if this is IST or SVT. If it is SVT it was probably exercise triggered, so I will address it with a cardiologist. I certainly didn't feel the jump from under 100 to over 150 I have had with previous SVT episodes (which were very short) or the thumping in my chest. Hoping it was just a slightly fast heart rate from exertion, stress and heat.

Thanks so much - typically it happened on a weekend so I can't address it easily until next week. I know the limitations of a watch versus a 12 lead.

Also anyone have experience of SVT and what works? I carry cold water - chuck it in the freezer overnight. Do breathing exercises daily and use them if I have a high heart rate.

OP I can't see a 'p' wave on that ECG, but it appears to be regular. This is good.

There are a couple of things that can slow it but I wouldn't do them unless taught by a HCP.

One you can try at home is to swallow a large lump of ice cream.

SVT is an abnormally fast heart rate, but you mentioned exercise, your HR normally increases on exercise, and with this heat your heart is working harder than it would normally.

In summary, get it checked but it is probably just a mixture of heat and exercise.

I hope you are currently dreaming of kittens and other soothing things.

I can't give any insight into your graph.

I've had SVT for 20 years and the way I can tell the difference between that and normal extertion induced fast heartrate is from the 'jump' and 'thumping' you mentioned. If I have a rapid heartrate 130-150 bpm and stop exercising and it starts slowing down naturally, it's not SVT. Also my SVT is faster than 150bpm.

My SVT cannot be stopped by resting. Adenosine used to be the only thing that worked for me. However, a few years ago I discovered the Modified Valsalva Manoeuver (Google it to see diagrams) and that works 100% of the time to stop my SVT.

Basically, you sit with legs out in front of you and your torso at a 45 degree angle. Hold nose closed and bear down for 15 secs. Quickly lie back and raise legs in the air. From my understanding this forces blood rapidly back to heart and that interrupts the SVT. Do Google it though.

Hope that helps

Thank you @sashh The lack of a P wave freaked me out, but maybe it was the watch kicking up over a bad contact on a hot day. I have been dreaming of kittens and just contacted a friend with some available - much better for the hr than googling arrhythmia!

Thank you @tessellated2 I will look up the Modified Valsalva Manoeuver and discuss it with my cardiologist. I naturally have low blood pressure and sometimes also get a POTs type reaction (the cardiologist noticed this), that doesn't reach the official criteria. Not fun at all. Always having a small bottle of fruit juice and a small bottle of ice seems to help a bit.