Hello all,
I'm new here, but after reading a bit and seeing that you are all so familiar with anxiety and palpitations, I thought you might be able to give me some insight on this recent situation of mine. To give you a little background, I've had heart palpitations for over 20 years, along with some random scary spells when the heart seems to quiver for a few seconds before picking up a beat. I've even fainted a time or two (though the last incidence of that was several years ago... knock on wood!) and chest pains come with the palps about 50% of the time. Laying on my left side or becoming upset or overly tired are guaranteed to start the palpitations. I can't even begin to count how many times I've been to hospitals and doctors for it over the decades, but it's been a LOT. Lots of blood tests, EKGs, heart enzyme tests, you name it. And they've all come back normal. The final diagnosis always ends up being chronic anxiety and panic attacks.

Early pre-menopause set in on me in 2009 (at age 40), which is not uncommon in my family. Along with that came... you guessed it; an increase in the number of heart palpitation episodes. I had EKGs, an echocardiogram, heart enzyme tests, general blood tests including thryoid testing, chest X-rays, and assorted other tests run in 2009 and 2010, exactly 1 year apart. All they found was trace mitral valve regurgitation in 2009, and trace mitral (which was less than the previous year's) and tricuspid regurgitations in 2010, both of which they said were just incidental findings on the echo reports and nothing to be concerned about. They did see a few palpitations on the tests, but they were again attributed to anxiety, by several doctors. I decided to stop camping out at doctors' offices then and went only for injuries and yearly checkups afterward.
At my last checkup (July 2012) I had a full panel of fasting bloodwork done, including a thyroid test, vitamin/mineral panel, liver enzymes, hormone tests, and an EKG. All was perfectly normal, though they did see a couple of palps on the EKG, which didn't concern the doc since I had warned him ahead of time that I was feeling panicky, and we've seen those palps so often before. So, now that I've given you my life story (LOL), I'll get to the point:

Right after that I had a mild neck injury which progressed into a frozen shoulder, so for the better part of a year I have been pretty sedentary, doing only the exercises suggested for physical therapy (for the shoulder) and some light house work and stretching. I have been increasing my activity levels around the house over the past couple of months, as the shoulder is finally becoming less painful. Today I tried raking leaves and had a rather scary episode though. After about 15 minutes of raking at what I consider an average walking pace, my heart began to pound very hard and I got short of breath. I was breathing deep enough, but it just felt like I wasn't getting enough air no matter what. I also felt a bit weak and my head felt sort of "floaty" (?). Nothing hurt, but it really scared me. Especially considering that I was NOT having any heart palpitations (go figure!) I sat down and concentrated on taking slow deep breaths, which was hard when I felt like I needed to breathe faster, until I felt like I could breathe at a normal pace again. I felt pretty tired then.

I took my BP, HR, and O2 readings and they seemed off to me. The first reading was taken after I got in the house and sat down, which was maybe 5-10 minutes after the episode started. I was still a feeling a little out of breath and the heart was pounding about half as hard as what it was before I started the slow breathing:

My blood pressure was 90/61, which absolutely normal for me at any time, heart rate 79, and oxygen level 98%.

The second reading was taken maybe 5 minutes later when I felt like the heart had settled down pretty much to normal, and I was breathing much more normally too.

Blood pressure was 92/63 (again, normal for me), heart rate 76, and oxygen level 98%

Several things worry me about this. First and most obviously is the fact that such a simple exercise as raking leaves would cause me to pant and have a pounding heart. I mean, my "average" heart rate when puttering about the house during the day runs anywhere from 75-85, and my resting heart rate (like taken when I first wake up) is around 62. So that means I wasn't even really exerting myself! Could this be just a side effect of being out of shape? Or maybe I had a panic attack without realizing it and started to hyperventilate or something? I'm also confused as to how I could have had a blood oxygen level of 98% right after exercise, which isn't bad, when I felt so totally out of breath? I'm just really worried that maybe I *have* developed a heart problem or something. The really weird thing is, I didn't feel a single heart palpitation until later that night, when I was silly enough to roll onto my left side right before I fell asleep.

A friend of mine said she had the same problem (no exercise tolerance) when she was on some medicines, but I'm not on anything except for Zantac 75 twice daily to manage my acid reflux. Then she mentioned caffeine, but all I ever drink is water and the occasional glass of milk. I am not overweight... in fact I'm trying to figure out how to gain some much-needed weight right now, and aside from some insomnia from these danged hot flashes, I can't put my finger on what I could be wrong. Is it time to start badgering the docs again?