In this article, I will be discussing cardioversions, and how they can be helpful for patients who have atrial fibrillation.
So, first of all, what is a cardioversion? A cardioversion is an electrical shock to your heart to try to reset your heart, to get you out of Atrial Fibrillation, and back to Normal Sinus Rhythm. You may have seen on TV, or in a movie when somebody's heart stops, and they take the electrical paddles and give them the electrical shock to bring them back to life. Meanwhile, your favorite actor will yell usually -“Everyone Clear!”
A cardioversion is pretty much exactly the same thing, except a lot less dramatic. Basically, what happens is that you get electrical current applied to your heart to reset your heart, and to try to bring you out of AFib and back into normal sinus rhythm. I usually tell my patients that it's kind of like when either your telephone or your computer is not working, and you turn it off and you turn it back on again to reset it. The same exact principle, the same exact idea in terms of what a cardioversion actually does.
Now, you may see YouTube videos of somebody getting a cardioversion and it's a very painful experience, and you see them jumping out of the bed. Again, that is a very dramatic example, and in an emergency setting where people need to get a cardioversion done for usually something that's life-threatening, there is usually not enough time to actually give people proper sedation, and it can be very painful in those situations. However, when you get a cardioversion set up with your doctor, and get it set up as an appointment, it is usually a fairly painless procedure. I always schedule mine with an anesthesiologist, so that I make sure that you don't feel anything, and so typically, you're getting very strong sedation medication which only lasts for a few minutes. Once you're deep asleep, your doctor will go ahead and do the electric shock treatment, which typically involves putting pads on your chest in the front and as well as in the back, and applying that electrical current.
Why should a patient do a cardioversion? What is the benefit of doing a cardioversion? Well, the main benefit is to get somebody out of Atrial Fibrillation. But well does a cardioversion actually work? Does it actually get somebody out of Atrial Fibrillation? So, I usually tell my patients that the cardioversion itself usually works. In my experience, the actual shock treatment works probably about 90% of the time to actually get a patient out of Atrial Fibrillation. Now, that doesn't mean the Atrial Fibrillation can't come back. There's an inherent short circuit problem or a problem with a patient’s heart which is triggering episodes of Atrial Fibrillation, so, the AFib may come back an hour later, a week later, or a year later, there is no good method to predict if or when the AFib will come back. Usually, changes in medication are required after the cardioversion in order to help keep you in a normal rhythm.
A cardioversion is only beneficial for people who are in what's called Persistent Atrial Fibrillation which means you are in Atrial Fibrillation all the time. If your AFib episodes come and go, a cardioversion is not the right treatment for you, but if you're in AFib consistently, it may be a beneficial treatment option for you. However, I will say when it comes to the success rate of a cardioversion, the longer somebody is in Atrial Fibrillation, the less likely the cardioversion will be successful.
As I have mentioned several times in past articles, the longer people are in Atrial Fibrillation the more heart inherently changes, and then it makes much harder to control or stop the Atrial Fibrillation. As a result, if somebody's been in AFib consistently for a couple years, I usually don't even try a cardioversion because the success rate can be pretty low, but if you've been in AFib for several months or even a year, it can be beneficial, and it can be successful.
What typically happens during a cardioversion procedure? It is typically scheduled as an appointment with your cardiologist or electrophysiologist. In my case, I always schedule it with an anesthesiologist. You get an intravenous put in place, once everything is in position and ready, you get heavy sedation medication which will only put you to sleep for only a few minutes, and once you're asleep we apply this electrical current to your heart to help reset your heart. Typically, it only takes a few seconds to do. Once you're awake, typically patients can go home. Again, I typically provide medication adjustments after a cardioversion in order to improve the success rate of the procedure and to keep the AFib from coming back. When it comes to a cardioversion shock, there are different ways to actually deliver that shock, there are different levels of energy, there are very low amounts, and there are higher amounts. The amount of energy is frequently dependent on a patient’s size: people who are more overweight are going to require higher energy because you just have to get through more tissue to actually try to reset your heart.
So, when do I recommend a cardioversion to my patients? The first example would be when patients have symptoms, and they need something done very quickly. I see a patient in my office, and they are very short of breath or very tired, I can do a cardioversion on them quickly because that's probably the most rapid thing that I can offer to them. I can offer them cardioversion on the same day or the next day to help get them out of AFib and improve their symptoms. Long term, other options such as an ablation may work better, but in the short term, a cardioversion can be a very useful treatment option.
Another example in which a cardioversion may be a useful treatment option is for people who have very subtle symptoms, and you don't really know if it's the AFib or not causing the symptoms. If you have persistent AFib and you feel tired, or rundown, or short of breath, but all your numbers look okay: the heart rate is okay, the heart function is okay, but it's not really clear if it's the AFib itself causing some of these additional subtle symptoms, the only way to know for sure is a bit of trial and error, and that is to get a patient out of Atrial Fibrillation. In a patient with subtle symptoms, I frequently give a trial of cardioversion to see if it actually is helpful, "Can we get you out of AFib? Does it change anything about how you feel?"
What are the risks of a cardioversion? A cardioversion is usually a straightforward procedure. It's a procedure that I tend to do first on people who I think are too sick, or have too many medical conditions to undergo more aggressive treatment options like an ablation. So, it is a treatment of choice although it sounds pretty dramatic to have a shock done to your heart, is actually much more benign compared to other procedures that are done for Atrial Fibrillation.
So, what are the main risks involved with a cardioversion? The main risk is the risk of stroke. The risk of strokes arises if you have a blood clot inside your heart because that blood clot, if you apply a shock current, may potentially dislodge the blood clot and can give a patient a risk for stroke. So, there are a few ways to mitigate that risk of blood clot and the risk of stroke during a cardioversion. First, if somebody's on blood thinners consistently, such as for several months, the chances of having a blood clot are very low, and usually, it is safe to proceed straight with a cardioversion. But for people who do not take strong blood thinners, or they have not been on strong blood thinners for very long, I usually check them for a blood clot with what's called a transesophageal echo. I usually do it together all at the same time. When they're asleep, I put a tube about the size of my finger down your mouth and into a patient’s esophagus, and that takes very clear pictures of your heart just to make sure there are no signs of a blood clot. Provided that it is clear, right then and there, we do the cardioversion and get the person back into a normal rhythm.
I do have patients who have asked me, "What happens if you restart your heart and it doesn't want to come back or comes back too slow?" Fortunately, I have not seen that happen. The heart is very resilient and the heart rate comes back. There are several times it can be very slow after a cardioversion and require a decrease in medications. There's actually only been one time in the hundreds of cardioversions that I've done where a patient’s heart rate was too slow, where I ended up needing to put a pacemaker afterward, but that is very, very rare. Usually, the heart rate is perfectly acceptable after a cardioversion, but again it does frequently require some medication adjustments.
But for many people, a cardioversion can be a very successful treatment option to provide a rapid relief for symptoms from Atrial Fibrillation. It is not nearly as dramatic as the videos that you see on YouTube when done in a nice controlled setting, and the pain is controlled adequately, and your sedation is controlled adequately. As always, please discuss with your doctor if a cardioversion is the right treatment for you.