I’ll pile on the “had RF ablation, not cryoablation” experience cause I’m bored and who knows, might provide some insight.
First off, I am an Emergency Med MD and have treated folks with acute SVT’s and (A. fib/flutter…and much worse for that matter) for near 30 years. Who better to know when they are having runs of SVT right!!!
I’m a 56yo, 6’5", 210-220lbs typically - a big dude not particularly suited to endurance events but luckily for me, there is no rule that says you can’t partake even if you suck…so I do 'em…and have since the early nineties. I did many a tri in my speedos for chrissakes. For many years, I would have a brief palpitation/flutter sensation typically immediately after a hard effort where I would be trying to settle back in to a steady rhythm…think trying to maintain momentum over rollers. They were very self limited and seemed to improve/go away with better conditioning as each season rolled along. Like many I had a period of time away and when I was turning 50 I decided I would get back into it and do a 70.3. I recall while training having a few flutters but not being particularly bothered by it…nothing sustained. Race day I for me nailed the swim and bike and was settling in to my shuffle/run when about a mile in I just couldn’t catch my breath. I didn’t feel the typical onset flutter or anything but just lost my energy. I felt like my chest was tight and went so far as to take my HRM strap off. I kept at it and ultimately straggled across the line just to say I did it. I attributed it to just being out of condition for an event of that duration. The next year I was doing 70.3 Boise and I knew I was not in as good a condition as I should be so was actually going pretty reserved. Coming in on the bike leg in a decent descent from Micron to the river with one little roller that if you give it some stick you can maintain some speed. I gave it some stick over the top, settled into my extensions then immediately felt like I was passing out and felt my heart flutter and continue - my heart rate was steady 140bpm no matter what. My energy was gone. I coasted pretty much back to T2, felt like crap but decided to push on and tried to run…but couldn’t…at all. I walked and passed my wife at about mile 3 and told her I was sitting down at next aid station and if it didn’t settle down I was quitting (I’d never quit before). The aid station was in wide open direct sunlight so I just said hell with it and pressed on. In the shade of the greenway, my back started feeling really stiff so I did a hip hinge/squat, stood up…and felt fine!!! My heart rate was suddenly 95. I had my eureka (you’re an Emergency doctor for hellsakes moment) and realized I’d been having SVT all along. My heart tracing from that race is awesome and tracks it perfectly.
I knew what situations triggered it for me - hard effort, deep breath, settle in…SVT. I could pretty much avoid it by simply not doing those type of things - keep things nice and steady. I had a few more brief episodes training and racing (some I thought might just be anxiety about having SVT) then I had a very long episode at 70.3 CDA that began in the swim about halfway. I was swimming nice and steady, just about to first L turn when a person next to me just went straight sideways over the top of me. I took a sudden big breath out of rhythm…SVT, heart rate 140. My immediate thought was get to a paddle board but I calmed myself down, sort of doggy paddled around the corners to the long home stretch swim in and said “either quit or suck it up and swim” I swam in and that was the most fatigued I have ever been in my whole life. I literally would have laid on the beach like a washed up whale if there wasn’t thousands of people watching and cheering. In T1 I tried multiple valsalvas/squats/sitting/laying…nothing worked…so I did what any self respecting “paid a bunch of money to do this” athlete does and took off on my bike. I had no energy. I got passed by everybody. At mile 24.9 going up gentle grade…it stopped…I felt fine…and I took off and actually finished out my day feeling not too bad minus the 1.5 hour SVT spell.
SVT can be really variable in how people tolerate it. For me, at it’s onset it would cause a very brief, almost syncopal feeling - I would get a feeling of the ground rushing up at me of sorts…then my energy would just be gone. That’s probably because when it occurs often the atria are contracting against AV valves snapped shut by the already contracting ventricles…and it makes you feel like shiz. I decided I needed to do something about it, saw an EPS Cardio and wore a monitor for a month. We caught a few episodes of fo’ real SVT at 140 rate but also interesting several episodes of MAT (multi-focal atrial tach) with rates to 190. I had RF ablation with Propofol sedation, took 5 hours and he found 4 ectopic atrial sights that triggered the MAT with rates up to 190 and a typical accessory track for SVT - and ablated all those. When I woke up, I was whoooooped - I mean really tired and my chest was heavy. I thought I might be having an MI but saw the post procedure EKG looked perfect. I had some bleeding from my right inguinal access sight with a whopper hematoma but all in all it was a piece of cake deal…I’d do it again right now if I had to.
I researched before hand and, it’s mostly anectdotal, but the folks that really took the time to heal and didn’t press their heart rates up seemed to have much less recurrence/failure. For the next two years I pretty much became a Zone 1/2 zombie…and I loved it. I took a beta blocker for those two years as well - I had alot of PAC’s initially but they settled down. I can spin along forever now like that…used to bore the shiz out of me. I’m in year 3 now post procedure and turning up the throttle quite a bit more - I sustained HR’s in high 160’s for duration of the local time trial last Wednesday…my max is probably 172/173. I haven’t felt a flutter/flip/anything since my procedure. I quit taking my beta blocker as well this year.
There is a saying in amongst medical folk that “A. fib begets A. fib” or “SVT begets SVT” which basically means the more a heart goes into it, the more it goes into it…that was certainly my experience. I committed myself to a long period of sustained low heart rate training to really iron in my normal sinus rhythm pathways and would encourage anyone that has this to do similar - I would not rush back to high, sustained HR efforts…unless your career as a pro-cyclist/triathles/runner, etc necessitates getting back at it sooner.
It’s a frustrating deal, can be very individualized, and wish ya’ luck on sorting it out!
it went on for some hours, ended up in ER.