If you have symptoms that concern you, it would make the most sense to get your yearly physical at your doctor and tell them what's going on.
Also, in addition, to the above suggestion to see a Dr., you may want to consider buying a heart rate monitor to use during your exercise.
Thanks for the replies:)
I forgot to mention that I actually go to a cardiologist, also a neurologist, psychiatrist and a CBT therapist. (besides "anxiety" I was diagnosed with: tetany syndrome (EMG test), overactive sympathetic nervous system, neurocirculatory asthenia (neurasthenia) - I was told all those are basically the same thing).
I had done ECHO, couple ECGs, yesterday I wore a 24h Holter (I am getting the results next Monday) and the day before yesterday I had a cardiac stress test, I had to stop at stage 3 (out of 5) because my heart was pounding so hard that it felt like it was gonna stop or something. HR was "only" 147 (during my first panic attack when ambulance arrived it was more than 200, but didn't beat as hard). Cardio told me the finding was negative even though I didn't finish the test and wrote that I couldn't finish because I got "SVT".
@VCJohnson: Do you mean like one that only monitors the heart rate or an advanced one with electrodes? I'm asking because I actually feel my heart rate almost all the time, especially when exercising :/
I meant only one that monitors the heart rate (also GPS etc if you want that).
If you don't like wearing chest straps, there is one by Scosche called the Rhythm+. I use it and like it, very comfortable. It's an optical pulse reader, worn on the upper side of the forearm, just below the elbow. It measures within 1-2 bpm of what my Garmin chest strap reads, when I temporarily wore both simultaneously, just to verify accuracy of the Rhythm+. It links by ANT+ to any wrist-type watch that is ANT+ or Bluetooth compatible, for heart rate signals. My Schosche Rhythm+ is linked to my Garmin watch. No chest strap required. I always wear it during running and cycling.
"Cardio told me the finding was negative even though I didn't finish the test and wrote that I couldn't finish because I got "SVT"."
So you were on the treadmill, and you had to stop the test after a level change. The physician noted that you were in SVT? Didn't he find this of significance? SVT or supraventricular tachycardia a sudden an immediate jump in heart rate. Quite often, people think it's a panic attack when it really isn't. The feeling you get in your chest during an SVT episode is unmistakable. It's not pain, but a tightness, or like a weight is on your chest. If you palpate your pulse, you'll find it racing probably faster that you can count it. A heart beating 3 to 4 time per second in very hard to count. Sometime, the heart will try to break into SVT but the circuit causing is can't support full conduction. In that case, you can have an erractic, pulse as you described, with several beats of SVT (or maybe even VT) followed by NSR, then a repeat. I had many occasions, especially at rest when my respiration was normal, and body my was "quiet" that I would break into SVT, but feeling my pulse in my wrist, I could feel normal beating. Eventually though, my heart would break into full SVT and an episode would commence. Have you experience this rapid beating before?