What is ventricular tachycardia?

I'm Dr. Suraj Kapa, a Mayo Clinic cardiologist specializing in heart rhythm disorders. Today, I'm going to talk about the condition known as ventricular tachycardia. Now, if you go on the internet and you look up ventricular tachycardia, you might find yourself concerned because people tell you, oh, this is associated with sudden death, or, oh, you might have to seek urgent medical attention. But I'm going to try and clarify things for you a little bit, both about what this might be and how we might go about treating it.

Ventricular arrhythmias can occur in both structurally normal and structurally abnormal hearts. What we mean by this is that there are some patients out there who really have no other underlying heart disease except some abnormality in their electrical system of the bottom chambers of their heart, or the ventricles, that can cause the heart to go out of rhythm. These can appear as occasional extra beats that one might experience as skipped beats, or as a rapid array of beats that are occurring all in a row, termed ventricular tachycardia. In rare cases, if the heart is structurally normal, this can actually result in a dangerous rhythm, though again that's relatively rare if there's not some other underlying heart disease that might be contributing.

Now, in some patients, however, they can have an abnormal heart for other reasons. There are a variety of reasons that the heart can become structurally abnormal, such as if you've had a heart attack in the past, if you have some sort of genetic abnormality that you might have inherited from your mother or your father. You might have some inflammatory disorder of your heart, such as sarcoidosis or myocarditis. All of these different syndromes can contribute to electrical abnormalities in the bottom chamber of the heart as well, but sometimes, when people have what we call substrate, or abnormalities of the normal heart architecture, this can lead to ventricular arrhythmias. And in these patients, these ventricular arrhythmias can potentially be life-threatening.

When we look at these arrhythmias happening, however, we have to take a systematic approach to their evaluation and to their treatment. So what do I mean by this? When we talk about evaluation, we're looking to see, Is there another reason they happened? Was there a medication you were placed on, was there some abnormality in your electrolytes, or what you were taking for other reasons, such as over-the counter herbal remedies, that might have contributed to why you might have those arrhythmias, and in fact they might go away if we do nothing else?

We're also trying to figure out how significant the arrhythmia is. Is it something that is life-threatening, or is not, because not all of them are. And then when we talk about treatment, we're looking really at two large areas. In those patients who don't have dangerous ventricular arrhythmias, we're looking to treat to improve quality of life, or symptoms, because some patients can have a variety of symptoms attributable to these arrhythmias, including feelings of skipped beats or rapid heart beats, or even dizziness. But some might just feel tired.

But then, the other group we worry about is the ones in whom these arrhythmias can potentially be mortal. In other words, they can lead to sudden death. In those patients, we like to risk stratify to figure out are these arrhythmias dangerous, and how do we protect those patients from dying suddenly.

The mainstay of treatments you might see if you go online is something called a defibrillator. You might have seen this on commercials or on TV shows where people are running about with these pads, drop them on a patient, and then provide an electric shock. This is what a defibrillator does for those patients who have the more risky ventricular arrhythmias. It sits in your body all the time, and then basically gives a jolt of electricity if your heart goes out of rhythm in order to restore it to normal rhythm. But the defibrillator doesn't prevent the arrhythmias from happening, it just is there to save your life in case they do.

In order to prevent the arrhythmias from actually happening, there are two mainstays of therapy. If we cannot find another reversible cause, we can either provide you with medications, and there are a variety of medications we can use. These medications are termed anti-arrhythmic drugs, and tend to be successful in as many as 50% to 60% of patients. However, they can have side effects, and in some patients they can actually cause more arrhythmias, and sometimes dangerous arrhythmias that could lead to sudden death, as well. As long as patients are properly monitored and the initiation of the drugs is properly done, however, the likelihood of this is very low.

Thank you for joining me today to learn more about ventricular tachycardia. In the next video, I will go into more detail in what an ablation procedure involves.