A lot of people have asked me questions about my disorder, because even my nurse friends have never heard of it. One of my aunts recently asked me if there was somewhere on the internet she as someone who doesn’t know much about medicine could go to learn about my heart problem.
Surprisingly, the answer is, not really. The information that is available through a simple google search is primarily from 2003 and before. It is both outdated and flat-out wrong according to more modern research. As a health care professional, I had access to the most current peer-reviewed journals and research, and I still am not quite sure what to tell people about my disorder. The problem is, there aren’t enough people who have it for there to be good, solid research on it. One of the major midwest clinics that specializes in rare disorders did a two-year study on IST that they published. In two years, they saw 9 patients with the disorder and a handful more who qualified but were unsymptomatic.
You see, this disorder has been documented for a very long time, but it is still not well understood. It wasn’t given its current designation until 1979, when it was labeled Inappropriate Sinus Tachycardia (IST). It generally becomes symptomatic in women aged 20-40, and seems more prevalent in women who work in health care.To explain what it is, I’ll have to go into a bit of a lesson about the “normal” rhythms of the heart. Bear with me.
Sinus rhythm is the rhythm most people are in most of the time. It is the “normal” baseline. Sinus rhythm means the atria are firing before the ventricles to efficiently push blood through the system, and that the rate of beating is between 60-100 per minute.
Sinus tachycardia happens when the heart still beats in the right pattern, but the pattern speeds up. 110 beats per minute, 130 beats per minute, 140 beats per minute. This can push into another rhythm known as supraventricular tachycardia or SVT, which basically means everything above the ventricle can’t beat fast enough to keep up. The heart can beat as fast as 150 to over 200 beats a minute in this rhythm.
Wait a minute… sinus tachycardia can be normal though, right? Correct! Sinus tachycardia is perfectly normal in certain situations. Like when you exercise heavily. Or when you have an adrenaline rush in a situation of danger.
The trouble with IST is that sinus tachycardia happens when it is NOT normal (when it is inappropriate). When sleeping, sitting quietly in a chair, standing up, walking slowly to the bathroom, driving a car, playing a video game, reading a book, watching TV… you get the idea.
IST is characterized by an elevated heart rate all or most of the time, with spikes of the heart rate well over the “normal” range during very mild exertion, very mild stress, or even just being irritated by some dumb kid on the internet. The elevations in heart rate are prolonged and difficult to control with medications. They lead to severe chest pain, nausea, dizziness, lightheadedness, syncope (passing out), and palpitations (you can feel your heart beating forcefully as if it’s trying to punch its way out of your chest, or maybe doing some flip-flops for fun in there).
Consider that the “target” heart rate for an average person doing a 20 minute exercise routine for heart health is somewhere in the 120-130 range. Then consider that folks with IST have a heart rate in that range or higher for hours and hours a day. Even when they are just sitting in a chair doing nothing. It takes an enormous amount of energy to run the heart that fast, and leaves you feeling fatigued, drug out, and emotional.
IST is not caused by anxiety (it was ruled out), thyroid imbalance (also ruled out), or any other hormonal or emotional problem. I’ve had six months of extensive testing, some of it invasive, and all of it difficult to endure. My cardiologist says this disorder cannot be faked and that all other possible causes have been ruled out in my case. My endocrinologist and sleep pathologist and general practitioner didn’t know what it was until I explained it to them. Yeah, it’s really that rare.
The current research and guidelines on IST say that there are three treatment options.
1) A drug class called beta blockers – these slow the heart. They also cause severe side effects in many people, including low blood pressure, passing out from low blood pressure, severe depression, and in men, impotence. My doctor has tried several of these, including metoprolol, inderal, and bisoprolol. The first two caused depression and fatigue so severe I stopped caring for my own needs. For a couple weeks at a time while trying to adjust to the meds, I rarely showered, missed 1-2 meals a day… even brushing my teeth was just too much work. I became suicidal, but fortunately didn’t have the energy to act on those thoughts. Bisoprolol, so far, is only causing low blood pressure and more dizziness, to the point that it is no longer safe for me to drive a car.
2) Calcium channel blockers – these also slow the heart by working on one of the molecular pathways that allow electrical signals to flow smoothly and quickly along the heart. They have been shown to be effective in a small percentage of people with IST, and they come with a host of side effects of their own.We tried this one, too. Cardizem caused me severe and continuous chest pain. For about a week, I felt like an elephant was sitting on my chest. It was hard to breathe, and I couldn’t even walk to the bathroom without assistance toward the end.
3) Surgery called ablation for cases that are very severe and which cannot be controlled with medication. The surgery was once thought to be a complete cure, although symptoms persisted in many people despite having a clinically measurable lower heart rate. The ablation surgery carries risks of damage to the nerves that control the diaphragm (ie breathing), perforation of the heart, inadequate destruction of the electrical initiation cells (SA node) of the heart resulting in a need to repeat the ablation (sometimes over and over again), over destruction of these cells resulting in too low a heart rate and the need for a pacemaker. Further, the SA node can grow back, requiring the surgery to be repeated in 3-6 months, even if it looked completely successful. The surgery also carries the risks of death, brain damage, stroke, and further disability. The risks are considered moderate for most people, but surgeons hesitate to place a pacemaker in someone my age. Pacemakers have risks of their own, including massive infection, dysfunction of the machine, frequent need to monitor and recalibrate the machine, and the need to replace the machine every 5-7 years. My doctor has talked about this as an option for me. He thinks it might help. The risks and long-term complications (like a pacemaker) have to be weighed against my daily life without the surgery, though, and the only person qualified to make that decision is me.
IST is not life-threatening. It is not going to shorten my lifespan. Very few people who get IST progress to any sort of heart damage even after years of elevated heart rates. My arteries are clear. My muscle works fine.
Knowing that, knowing that I will not die from this disorder no matter how much it changes my life, makes facing the risks of repeated surgeries and implanted devices seem unwise to me. The truth is I am here today with my husband and my son. I can still type, read, write, sing (if a bit breathlessly), cook a meal (if I pace myself), and enjoy spending time with my guys.
Yesterday, I was playing an online game and a 15 year old kid said something to me that kind of ticked me off. Not “blow a gasket” pissed off. Just sort of annoyed. I could barely speak for the palpitations. My heart rate was over 140. My hands were shaking so bad that I couldn’t type the reply my brain was cooking up. I am not a docile person. My wit is sharp and my tongue has been known to be even sharper. I turned off the computer and sat there staring at the screen. I could not walk away, for fear of falling on my face. It took over an hour for me to start feeling “normal” again enough to get up and walk around.
Life with IST isn’t easy. I could waste my energy railing against how it isn’t fair (it isn’t), or how I wish it would just go away (I do). I could just follow through with one of those suicide plans I thought up while on the depression-inducing beta blockers.
But I’m not a whiner. Or a wisher. Or a quitter. I’m just me. Fast heart and all.
UPDATE: So many of you have expressed thanks for this post and asked after me over the years since I wrote it that I felt an update was in order. You can find more information about how I’m doing now (2013) here.