Ventricular tachycardia: What can help?

Like pacemakers, implantable cardioverter-defibrillators (ICDs) are implanted in the chest area – under the skin or chest muscle – in a minor surgical procedure. The device is connected to the heart by thin wires (leads) that have electrodes at the end of them.

The ICD monitors the heartbeat. If it detects ventricular tachycardia, it sends one or several controlled electric shocks to the heart. This can quickly restore a normal heart rhythm and lower the risk of complications.

An ICD may be suitable for the following people, as long as they also take the necessary medication regularly (for example, ACE inhibitors) and are expected to live longer than one more year with a good quality of life:

• People who have already had episodes of ventricular tachycardia or have been reanimated after sudden cardiac death – unless the underlying cause can be treated and eliminated.
• People who have a higher risk of ventricular tachycardia with life-threatening complications due to another heart condition – even if they've never had ventricular tachycardia before. These are often people whose heart has not completely recovered from a heart attack. The risk of ventricular tachycardia and sudden cardiac death is considered to be higher if symptoms such as weakness or shortness of breath don't go away after a heart attack and the heart's ability to pump blood is still affected weeks later. The aim of implanting the ICD is to prevent these complications.
• Those whose heart is weak for other reasons. People who have severe heart failure are often given an ICD as part of their cardiac resynchronization therapy (CRT). Then the role of the ICD is not only to act as a defibrillator when needed, but also to make sure that the chambers of the heart (the atria and ventricles) are pumping regularly and effectively.

An ICD can also help in people who are waiting for a heart transplant.

Good-quality research has shown that an ICD helps to prevent sudden cardiac death in people who have a higher risk of ventricular tachycardia and related complications. According to the research, within two to three years

• 8 out of 100 people who did not have an ICD died of sudden cardiac death, and
• 3 out of 100 people who had an ICD died of sudden cardiac death.

ICDs can also record data – for example, on how well the heart is pumping blood or when they sent an electric shock. Some of these devices can also regularly send this information to a doctor's office or hospital (telemonitoring) so that necessary tests can be done or the treatment can be adjusted, for instance. These additional functions can prevent cardiovascular complications that are sometimes life-threatening. It is not clear whether they can increase life expectancy, though.

The main risks of treatment with an ICD are infections, bleeding, wound-healing problems and device malfunctions. If the ICD malfunctions, it may send bursts of electricity that aren't needed. Overall, about 3 out of 100 people with an ICD develop complications, and about 1 out of 100 develop complications that are severe or even life-threatening.

If you notice episodes of ventricular tachycardia, you will also feel the bursts of electricity sent by the ICD. That is often unpleasant or painful and can be frightening and distressing.

Although an ICD can stop ventricular tachycardia, it can't prevent it. To keep the number of episodes to a minimum, medication or cardiac ablation are used as well.

It is generally possible to switch an ICD off. This can be done without having another surgical procedure. Some people might decide to do that in the final stages of their life – for example, because their heart disease is so severe that the device would send electric shocks too often.

Catheter ablation (sometimes called cardiac ablation) involves "deactivating" the parts of the heart that are responsible for the ventricular tachycardia.

A doctor inserts a flexible tube called a catheter into a blood vessel in the groin and then gently pushes it through to the heart. First, the catheter is used to perform a procedure called an electrophysiology (EP) study. Targeted bursts of electricity are sent to trigger the abnormal heartbeat. That way, the doctor can see exactly which area of heart tissue is causing the ventricular tachycardia. Then the tissue there is ablated (destroyed) right away – typically by heating it with electricity until a scar forms. The ablation is usually done under brief, light anesthesia.

This procedure is especially recommended if

• some of the heart tissue is scarred from a heart attack, and that is causing a lot of ventricular tachycardia episodes despite using medication – so the ICD often sends (or would often send) bursts of electricity,
• treatment with medication is either not wanted or not possible (for instance, because the medication is not well tolerated),
• the ventricular tachycardia is being caused by problems in the electrical pathways of the ventricles, a hereditary disorder affecting the electrical activity of the heart, or a congenital ("at birth") heart defect.

If the heart is otherwise healthy – in other words, you don't have coronary artery disease (CAD) or any other heart problems – and you still have ventricular tachycardia episodes, then experts recommend catheter ablation rather than using medication over the long term. But this procedure can only be done if the area of the heart causing the ventricular tachycardia can be clearly defined and easily reached with a catheter. People whose heart is otherwise not damaged do not need an ICD. Sometimes people who have persistent ventricular tachycardia due to CAD are advised to have cardiac ablation instead of an ICD. But only if their heart is able to beat strongly enough to keep their blood circulation stable despite the abnormal heartbeat.

Researchers have looked into the effectiveness of cardiac ablation in preventing ventricular tachycardia and related complications. So far, most of the people in the studies already had an ICD because of coronary artery disease. That research suggests that – in these people and compared to medication – cardiac ablation is better at preventing further episodes of ventricular tachycardia, as well as the necessary but painful and distressing bursts of electricity from the ICD. But it's not clear whether catheter ablation can increase life expectancy more than medication can.

Catheter ablation leads to complications in about 4 to 11 out of 100 people whose heart is already damaged by coronary artery disease. These complications include injury to the heart or blood vessels, bleeding, heart rhythm problems, a heart attack and stroke. Up to 3 out of 100 people die during the procedure or shortly after. The risk of complications is much lower in people with an otherwise healthy heart, though.

Beta blockers are often used. They have been shown to prevent life-threatening complications such as ventricular tachycardia in people with heart disease. Beta blockers are usually well tolerated. The possible side effects include a slow heartbeat, low blood pressure and breathing problems.

Sometimes special anti-arrhythmics are also used. But there's no good scientific proof that they prevent life-threatening complications. There is only some weak evidence to suggest that the substance amiodarone could have a preventive effect.

Because a wide variety of anti-arrhythmic drugs are used to treat ventricular tachycardia, the possible side effects vary too. Many of the medicines can themselves cause an abnormal heartbeat. Other typical side effects include headaches, nausea and low blood pressure. Amiodarone can also affect the thyroid gland and lead to lung, liver or eye problems.

Additional medications are recommended for people with heart failure. They don't affect the heartbeat directly, but still help to prevent life-threatening complications such as ventricular fibrillation and sudden cardiac death. Blood-pressure-lowering drugs like ACE inhibitors can be used for this purpose.

Sometimes catheter ablation is not possible. Then the tissue causing the problem can be destroyed (ablated) by doing surgery on the heart instead. In rare cases, the tissue is destroyed using a special type of radiation therapy.

Other approaches aim to influence the autonomic nervous system in the heart: This system consists of calming (parasympathetic) and stimulating (sympathetic) parts. In some people at higher risk of ventricular tachycardia, it may be helpful to stimulate the parasympathetic nervous system or suppress the sympathetic nervous system. This can be done in very different ways. For example, the nerve fibers of the sympathetic nervous system can be blocked in a surgical procedure. Not enough is currently known about the benefits and risks of these approaches. Because of this, they are only used in rare cases – for example, if other measures haven't helped.

To avoid increasing the risk of heart problems even more, you can try to lead a healthy lifestyle – for instance, by not smoking and keeping your weight in check.