What Is Catecholaminergic Polymorphic Ventricular Tachycardia?

Overview

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a rare inherited cardiac disorder that causes the regular electrical activity of the heart to be disturbed, resulting in abnormal heart rhythms (arrhythmia). The heart's electrical activity is largely regulated by the movement of calcium in and out of the cardiac cells; however, in CPVT, the movement of calcium is disturbed, causing extra heartbeats. Abnormal heart rhythms usually occur when a person is under high physical or emotional stress. CPVT often first presents in healthy children between the ages of 7 and 12.¹ If left untreated, CPVT can be lethal. In this article, we will explore the causes, signs and symptoms, the diagnosis, as well as the management and treatment of CPVT. 

Causes of CPVT

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is caused by inheriting a faulty gene from your parents. In a healthy heart, there is a precise movement of calcium in the heart cells, which control the heartbeat. In people with CPVT, the faulty gene causes this precise movement of calcium to become dysregulated, resulting in too much calcium inside the cell. Too much calcium inside the cell results in extra heartbeats originating from the heart's ventricles (lower chambers). This causes a rapid heartbeat called ventricular tachycardia.

Signs and symptoms of CPVT

The symptoms of CPVT occur during high physical or emotional stress. The symptoms are due to ventricular tachycardia.

Most common symptoms:

• Palpitations (rapid heartbeat)
• Fainting (syncope)
• Blackouts
• Dizziness

Cardiac arrest (heart attack) is another symptom of CPVT. It can be the first manifestation of the disease.

It is possible to spontaneously recover from ventricular tachycardia because, in some cases, the irregular heartbeat will self-terminate. However, in cases where the ventricular tachycardia does not self-terminate, it can progress into ventricular fibrillation, which can cause sudden death.¹

Diagnosis of CPVT

People with CPVT have a structurally normal heart with a normal resting electrocardiogram (ECG).⁷ CPVT manifests at times of high adrenaline (i.e. stress), so, assessing the heart at rest is not a good method for diagnosing CPVT. 

To check for CPVT, the heart will be monitored while you carry out an exercise, this is called a stress test. You will have electrodes placed on your chest, arms, and legs to monitor heart function while you raise your heart rate by running on a treadmill or pedalling on a stationary bicycle. 

If you are unable to perform either of these tasks, a Holter monitor will be used to capture a 24-hour ECG of your heart.

CPVT can also be diagnosed via a genetic test. There are various genes that may be responsible for CPVT. However, the most common is a defect in a gene called RYR2, which encodes a protein controlling calcium levels inside the cell.¹

Management and treatment for CPVT

Treatment for CPVT depends on its severity. People with CPVT usually have check-up appointments with their cardiologist every 6-12 months. There are various long-term treatments and management strategies, and these may be used in combination rather than relying only on one specific treatment. Generally, those with CPVT are attempted to be managed mostly with medications.

Physical activity

Your healthcare provider might advise you to restrict any restrict physical activity, particularly intense exercise.

Medication

Beta-blockers may be used to reduce the heart rate. Flecainide may be used to reduce the likelihood of arrhythmias without disrupting heart rate. The medication or combination of medications recommended to anyone with CPVT depends on their severity.

Implantable cardioverter defibrillator 

An implantable cardioverter defibrillator (ICD) is usually required for 1 in 3 people with CPVT whose symptoms are too severe to be managed with only medication. Having an ICD prevents you from participating in contact sports and restricts the type of work you can do. The ICD detects abnormal heart rhythms and sends electrical currents to restore the normal heartbeat. 

Left cardiac sympathetic denervation

This is a surgical procedure to reduce the amount of adrenaline affecting the heart. The surgery involves dividing the nerves going to the heart.

FAQs

How can I prevent CPVT?

It is not possible to prevent CPVT because it is an inherited genetic disorder. Nevertheless, it is possible to manage and treat CPVT effectively. So anyone with CPVT can have a high quality of life.

How common is CPVT?

CPVT is a rare disorder that affects 1 in 10,000 people.

Who is at risk of CPVT?

Because CPVT is an inherited disorder, this means that someone is more likely to get CPVT if their relatives have CPVT. 

You inherit two versions of the same gene - one from the mother and one from the father.

Multiple different faulty genes can cause CPVT.

• For some defective genes, you must inherit the defective version from both mother and father to get CPVT. 
• For the other defective genes, you must inherit one (or more) defective genes from either the mother or father to get CPVT. In this case, if either parent has the defective gene, then the child has a 50% chance of having CPVT.

When should I see a doctor?

If your family has a history of CPVT, getting your child tested for CPVT would be recommended. If your child shows any of the symptoms, such as fainting, blackouts, dizziness, or palpitations during high physical or emotional stress, then take them to see a doctor.

Summary

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited disorder that causes abnormal movement of calcium in and out of the cardiac cells, resulting in ventricular tachycardia. This results in symptoms such as dizziness, fainting, blackouts, and palpitations but can more seriously cause ventricular fibrillation and sudden death if left untreated. It is, therefore, essential to seek medical advice and treatment immediately if you suspect that you or someone else may have CPVT. There are many methods like physical activity, implantable cardioverter defibrillators, left cardiac sympathetic denervation or surgery available for managing CPVT. Which of these methods are used depends on the severity of the disease. In most cases, these treatment options are used in combinations rather than sticking to one method. Though prevention is not possible as the disorder is an inherited disorder, it is possible to successfully manage CPVT so you can have a high quality of life.