Catecholaminergic Polymorphic Ventricular Tachycardia

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited cardiac condition that causes sudden rhythm disturbances, called arrhythmias, in otherwise healthy children. These abnormal rhythms most often occur at times of high adrenaline levels, such as during exercise or strong emotion.

CPVT is a rare disorder that affects about one in 10,000 people. Left untreated, CPVT may cause the heart to stop beating.

The arrhythmias typically occur during exercise or emotional stress. It can cause a rapid heartbeat (palpitations), fainting (syncope), or cardiac arrest.

CPVT is caused by a change in the genetic code for a particular cardiac protein that causes it to leak calcium into the heart. The extra calcium affects the heart’s electrical system, causing extra heartbeats from the lower chambers of the heart.

Any child or young adult with symptoms of catecholaminergic polymorphic ventricular tachycardia during periods of exertion or strong emotion should be evaluated by an experienced team.

Because CPVT is only observable during periods of adrenaline, standard electrocardiograms and echocardiograms are not good diagnostic tests. Instead, if CPVT is suspected, your child will have an exercise stress test. This test utilizes a treadmill or bicycle and records the heart’s function during exercise. Younger patients too small for the treadmill may use a Holter monitor.

An exercise stress test can reveal a pattern of extra beats from the ventricles (ventricular ectopy), which become increasingly frequent and more complex as adrenaline release increases. These extra beats often develop into complex arrhythmias called “bidirectional” or “polymorphic ventricular tachycardia.”

Genetic testing is also an important part of the overall diagnostic work up for CPVT. This requires expert interpretation, often within the context of a whole-family evaluation.

There are several treatments for CPVT. Your child’s exact course of treatment will be based on the rate or severity of his or her arrhythmia.

Medications for CPVT

Many forms can be treated with medication, including beta blockers and antiarrhythmics. Beta blockers work by blocking beta-receptors and preventing adrenaline from affecting the heart. This helps slow the heart rate.

A common antiarrhythmic medication used for CPVT is flecainide, which works by affecting the sodium and calcium exchange within the cardiac cell. While very effective in some people with CPVT, it does not work for everyone.

Implantable cardioverter defibrillators

Implantable cardioverter defibrillators are devices often used in patients considered high risk, or those who continue to have symptoms after other treatment. They can detect ventricular arrhythmias and treat them by giving a precise electrical pulse to restore normal cardiac rhythm.

Left cardiac sympathetic denervation

When medical treatments don’t work to stop arrhythmias, your child’s doctor may recommend a day surgical procedure called left cardiac sympathetic denervation (sympathectomy). In this procedure, a surgeon divides the nerves going into the heart. This can prevent adrenaline from stimulating the heart and causing arrhythmias.

The cardiologists at Boston Children’s Hospital have years of experience treating CPVT, as well as other types of complex arrhythmias. The Center for Cardiovascular Genetics at Boston Children’s specializes in family-based services for children with CPVT, including counseling.

The Family Arrhythmia Clinic meets with and assesses entire families all at once, usually in one day. Our specialists use clinical and genetic testing to identify if any family member is at risk of developing the condition.