Hello,
First time poster here. A typical scenario is I'm sitting on the couch for an hour and then stand up. My HR might immediately jump from say 65 to 100, and then within a few seconds it might be 110 or even 120. But as soon as I start walking it will start dropping down to the 80's or 70's. Then if I stop walking and remain standing, it might go up again. If I sit it will come right back down. This doesn't happen every time, maybe once or twice a day and usually in the morning but has happened later in the day as well. I have taken my bp in the standing position during these HR spikes but it's either normal or more often elevated. I do not feel dizzzy, etc. and probably wouldn't realize something was wrong except if I was checking my pulse or wearing a chest monitor.
In addition, for the past few months, I'm also having two or three documented SVT attacks a week. These attacks are very different from the sitting to standing scenario just described. With the SVT, my HR will suddenly spike from normal to 190 for a period of one to ten minutes, and is not related to changing from sitting to standing. The SVT episodes end as quickly as they started. One second my HR will be 180 and within a second or two it will go back to 65. The EKG's are also different. When my HR elevates from sitting to standing, the EKG shows normal sinus rhythm and the return to normal when sitting is gradual. The EKG with the SVT attacks shows the SVT pattern. I have a Kardia ekg device so it's been easy to document.
Does the sitting to standing HR behavior sound like POTS? Or could it be somehow related to SVT or even a normal reaction to standing after sitting for a prolonged period of time? I also read there is something called inappropriate sinus tachycardia (IST) but maybe that's just an umbrella term including POTS. I started noticing these sitting to standing elevations over a year ago but it's probably been going on a lot longer. I'm a 71 year old male, normal BMI, walk daily, eat healthy, and have stopped caffeine and alcohol. Currently not taking any meds. I also have 5 to 10 ectopic beats per minute (PACs) which are probably triggering the SVT episodes. Any help is appreciated.
Jim