research update #3: ivabradine for POTS…

Well, this is my third and final post about the clinical trial studying the effects of ivabradine (brand name: Corlanor) on postural orthostatic tachycardia syndrome that I participated in over the past few months.

As you may remember from previous posts (see here and here), each participant would receive both the placebo and ivabradine for a month each, but as a double-blind study, neither the participant nor the doctor knew when we received each.

For the first month of the study, I experienced higher than usual resting heart rates, usually in the 80s. When standing, my heart rate would increase 30-40 bpm. Dizziness, lightheadness, pain, headaches, palpitations, and adrenaline surges were pretty standard for me – nothing out of the ordinary, but no improvement.

For the second month of the study, my resting heart rate was usually between 55-65 bpm. When standing, my HR would only increase by 10-20 bpm, but I almost constantly had a weird, slightly disoriented lightheadedness going on. Nothing that prevented me from accomplishing my ordinary tasks, but enough that I was constantly aware of it. Headaches and pain were standard, but palpitations and adrenaline surges felt much more prevalent (except for the day of the NE test, which I will discuss below). I do feel it’s important to note that halfway through the second month, my mother-in-law was diagnosed with cancer, and being a partial daily caregiver for someone who has 3-6 months to live is one of the more stressful events you can experience in life. That being said, the palpitations and surges occurred in the beginning of that month as well, so I don’t think caregiving had a measurable effect on them.

The test also measured my norepinephrine, epinephrine, and dopamine levels, both lying for 15 minutes and standing for 15 minutes. I have been hesitant to post the results of those catecholamine tests because I don’t think they’re representative of my everyday catecholamine levels. Catecholamine tests are performed in a vacuum – not literally, of course – but by controlling the external factors. You fast for 8-12 hours prior to the test, so any food or drink that you may consume on an ordinary day are not factored in. The test is conducted in a quiet, isolated room with few distractions. My test was conducted at the same facility my mom and I frequented for 18 months for her test, a facility that I became so comfortable navigating that during her appointments I would go make myself a cup of coffee using the Keurig in the nurse’s break room or stop at the nurse’s station to chat with the nurses. I am incredibly comfortable there and felt very relaxed on each day the test was performed.

My point is that a catecholamine test performed under those circumstances would produce very different results than one where I’ve had a normal breakfast, driven to work in morning traffic, and arrived at my office building with the bright florescent lights and typical background office cacophony.  That being said, here were my results:

Month 1

Month 2

So, yes, as you can see from the tables above, even on “calm” relaxed days, my norepinephrine more than doubles when I stand up. As a reference point, to qualify for the study participants must have a standing NE level of 600 pg/ml or greater. I asked the cardiologist what the NE of a normal, non- hyper POTS patient is, and she said probably somewhere in the 300s, and it doesn’t change much when they stand. I’d love to see where mine is at on a typical day, not under controlled settings.

Based on the lower resting heart rates and and slightly lower standing norepinephrine in month 2, I guessed that was when I was on ivabradine, and month 1 I received the placebo. I was right.

While ivabradine did a nice job of controlling my heart rate, the palpitations and weird disorientation make it not a great option for me. However, many POTSies have had great success with ivabradine, so please keep an open mind.

Although I don’t leave the experience with any new promising treatment for my POTS, I’m really glad I participated. I learned a lot about myself, both physically (I have hyper-POTS, the adrenaline rushes I get are real and measurable, I am more prone to headaches without a beta blocker, etc.) and emotionally (I can handle a lot in a month, including not being on medication, I’m probably better at talking to strangers than I think I am, and somedays it’s really hard having an illness that people, even researchers, don’t understand).

Compared to my rather mundane everyday life, I enjoyed the adventure. I also finally got to use my free voucher for $5.00 worth of food and drink.

“One way to get the most out of life is to look upon it as an adventure.” – William Feather

Smell ya later.
– Linds