Q: How serious is SVT? I have had it for 45 years and am now taking verapamil. For years I took Lanoxin. I see a cardiologist once a year. What advice can you give me to remain in stable condition?
A: Leading cardiologist Dr. Douglas Zipes replies: Supraventricular tachycardia (SVT) is a general term indicating a rapid heartbeat (tachycardia) coming from the top chambers of the heart—in essence, above (supra) the lower chamber (ventricular).
There are multiple kinds of SVTs, and without knowing the precise kind you have, I can’t be sure what to recommend. However, I can try to be Sherlock Holmes (the author, Sir Arthur Conan Doyle, was an outstanding physician known for his deductive reasoning) and deduce a diagnosis based on the following facts: you are female, you have had this since you were a teenager, and the SVT has been effectively (I assume) treated with digoxin (Lanoxin) for years, and now by verapamil.
On that basis, your SVT is most likely an atrioventricular nodal reentrant tachycardia (AVNRT) and is due to your heart impulse occasionally taking a wrong turn at the middle of your heart and ending up like a cat chasing its tail. Picture your local interstate highway and a cloverleaf exit that goes into town. If the exit instead doubled back onto the highway, when you drove off that exit you would end up back on the interstate, going around and around in a large circle. Your heart has that kind of short circuit, and that is what your heartbeat does when it develops the tachycardia: it takes that exit and goes round and round. We call that reentry, for obvious reasons. It occurs in a part of the heart’s conduction system called the AV node, hence the term AVNRT.
An electrophysiologist can put a catheter into the large (femoral) vein in your groin, thread it back into your heart, start up your SVT, find that faulty exit, and burn it with ablation. That puts up a roadblock across the errant exit so your heartbeat cannot conduct there anymore, and that will cure your SVT.
Success rates are in the high 90 percent range, with complications of one percent or less. Talk to your doctor about having the procedure done. If I am right, it is a slam-dunk to cure your SVT and eliminate all your medicines.