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In ventricular tachycardia, an irregular electrical impulse starting in the lower chambers of the heart (ventricles) causes the heart to beat faster.

Ventricular tachycardia is a heart rhythm problem (arrhythmia) caused by irregular electrical signals in the lower chambers of the heart (ventricles). This condition may also be called V-tach or VT.

A healthy heart typically beats about 60 to 100 times a minute at rest. In ventricular tachycardia, the heart beats faster, usually 100 or more beats a minute.

Sometimes the rapid heartbeat prevents the heart chambers from properly filling with blood. As a result, the heart may not be able to pump enough blood to the body. If this happens, you may feel short of breath or lightheaded, or you may lose consciousness.

Ventricular tachycardia episodes may be brief and last only a couple of seconds without causing harm. But episodes lasting more than a few seconds (sustained V-tach) can be life-threatening. Sometimes ventricular tachycardia can cause the heart to stop (sudden cardiac arrest).

Treatment for ventricular tachycardia may include medication, a shock to the heart (cardioversion), catheter procedures or surgery to slow the fast heart rate and reset the heart rhythm.

Mayo Clinic cardiologist Suraj Kapa, M.D., discusses common misconceptions about 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.

When the heart beats too fast, it may not pump enough blood to the rest of the body. So the organs and tissues may not get enough oxygen. Signs and symptoms that occur during an episode of ventricular tachycardia are due to a lack of oxygen and may include:

Ventricular tachycardia may go away on its own within 30 seconds (nonsustained V-tach) or last more than 30 seconds (sustained V-tach or VT). Brief episodes may not cause any symptoms. But sustained VT can cause serious problems, including:

Many different things can cause ventricular tachycardia. It's important to get a prompt, accurate diagnosis and appropriate care. See your health care provider if you or your child has any problems with the heartbeat. In some cases, urgent or emergency care is needed.

Call 911 or your local emergency number if anyone has these symptoms:

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Ventricular tachycardia is caused by faulty heart signaling that triggers a fast heart rate in the lower heart chambers (ventricles). The fast heart rate doesn't allow the ventricles to fill and squeeze (contract) to pump enough blood to the body.

Many things can cause or contribute to problems with heart signaling and lead to ventricular tachycardia. These include:

Sometimes, the exact cause of ventricular tachycardia can't be determined (idiopathic ventricular tachycardia).

In a typical heart rhythm, a tiny cluster of cells at the sinus node sends out an electrical signal. The signal then travels through the atria to the atrioventricular (AV) node and then passes into the ventricles, causing them to contract and pump out blood.

To better understand the cause of ventricular tachycardia, it may be helpful to know how the heart typically works.

The heart is made of four chambers — two upper chambers (atria) and two lower chambers (ventricles).

The heart's rhythm is controlled by a natural pacemaker (the sinus node) in the right upper chamber (atrium). The sinus node sends electrical signals that typically start each heartbeat. These electrical signals move across the atria, causing the heart muscles to squeeze (contract) and pump blood into the ventricles.

Next, the signals arrive at a cluster of cells called the AV node, where they slow down. This slight delay allows the ventricles to fill with blood. When the electrical signals reach the ventricles, the chambers contract and pump blood to the lungs or to the rest of the body.

In a typical heart, this heart signaling process usually goes smoothly, resulting in a resting heart rate of 60 to 100 beats a minute.

In ventricular tachycardia, faulty electrical signaling in the heart's lower chambers causes the heart rate to increase to 100 or more beats a minute.

Any condition that puts a strain on the heart or damages heart tissue can increase the risk of ventricular tachycardia. Lifestyle changes or proper medical treatment for the following conditions and events may lower the risk:

A family history of tachycardia or other heart rhythm disorders makes a person more likely to develop ventricular tachycardia.

Complications of ventricular tachycardia depend on:

Possible complications of ventricular tachycardia include:

A dangerous condition related to ventricular tachycardia is ventricular fibrillation (V-fib). In V-fib, the lower heart chambers contract in a very rapid and uncoordinated manner.

This irregular rhythm happens most often in people with heart disease or a prior heart attack. It may also occur in those with electrolyte imbalances (such as high or low potassium levels).

Ventricular fibrillation may cause sudden cardiac arrest and lead to death if not treated immediately.

The best ways to prevent tachycardia are to maintain a healthy heart and prevent heart disease. If you already have heart disease, monitor it and follow your treatment plan. Be sure you understand your treatment plan, and take all medications as prescribed.

Take the following steps to keep the heart healthy:

Ventricular tachycardia care at Mayo Clinic

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