Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT)

What happens in CPVT

Each heartbeat depends on calcium moving in and out of storage inside heart muscle cells. In CPVT, a faulty protein causes calcium to leak from storage when adrenaline levels rise. This triggers extra beats from the ventricles that can escalate into bidirectional ventricular tachycardia, where the ECG pattern alternates beat to beat, then polymorphic ventricular tachycardia and ventricular fibrillation, which stops effective pumping. See also paroxysmal ventricular tachycardia.

Because the trigger is adrenaline (a catecholamine), episodes happen during exercise, competitive sport, swimming, emotional stress, fright or excitement.

Genetics

• RYR2 gene variants, inherited in an autosomal dominant way (one copy from one parent is enough), cause about half to two-thirds of cases.
• CASQ2 and some other genes cause rarer recessive forms (both copies affected).
• Many cases are new mutations with no family history.
• Without treatment, a significant proportion of people with CPVT have a cardiac event by age 40.

Symptoms

• fainting during exercise or emotional stress, often the first sign
• palpitations or a feeling of the heart racing
• dizziness or near fainting
• episodes mistaken for epilepsy, because a fainting spell can cause jerking movements
• sudden cardiac arrest, sometimes as the first event
• unexplained drowning or near-drowning

Between episodes, people usually feel completely well.

Diagnosis

• Resting ECG: usually normal, sometimes a slow heart rate.
• Echocardiogram and cardiac MRI: normal heart structure.
• Exercise stress test: the key test. As heart rate rises, extra beats appear, then couplets, bidirectional or polymorphic ventricular tachycardia.
• Holter or implantable monitor to capture episodes during daily activities.
• Genetic testing for RYR2, CASQ2 and related genes. Once a variant is found, relatives can be tested.

CPVT is sometimes diagnosed after a sudden unexplained death through genetic testing of the person who died (molecular autopsy) and their family.

CPVT vs other inherited arrhythmias

Treatment

• Beta-blockers: the foundation of treatment, usually nadolol or propranolol, taken every day without missed doses. They blunt adrenaline's effect.
• Flecainide: added when beta-blockers alone do not fully control arrhythmias on exercise testing.
• Left cardiac sympathetic denervation (LCSD): a surgical procedure that cuts nerves carrying adrenaline signals to the heart, for people who still have events on medicine or cannot tolerate it.
• Implantable cardioverter-defibrillator (ICD): for people who have survived cardiac arrest or have recurrent events despite treatment. ICD shocks can themselves release adrenaline and trigger more arrhythmia, so medicines remain essential and devices are programmed carefully.

Lifestyle

• Avoid competitive sports and very strenuous exercise unless your cardiologist has agreed a plan. Some people with well-controlled CPVT can do selected activities after shared decision-making with an expert.
• Never skip beta-blocker doses.
• Family, school and coaches should know CPVT, how to perform CPR, and where the nearest AED is.
• Avoid stimulant medicines, high-caffeine energy drinks and recreational drugs.

Outlook

Untreated CPVT carries a high risk of sudden death. With diagnosis, consistent medication, and appropriate lifestyle measures, many people live full lives with few or no further events. Screening relatives allows treatment before symptoms.

Frequently asked questions

What are the symptoms of CPVT?

The main symptom is fainting or collapse during exercise, excitement or fear, typically in children and young adults. Palpitations and dizziness can occur. Some people are first diagnosed after a sudden cardiac arrest or a fainting spell mistaken for a seizure.

How is CPVT diagnosed?

Because the resting ECG and heart scans are usually normal, an exercise stress test is the key test, showing characteristic ventricular arrhythmias as the heart rate rises. Genetic testing confirms the diagnosis in many people and allows relatives to be screened.

Can people with CPVT exercise?

Traditionally, people with CPVT are advised to avoid competitive and strenuous sport. Some with well-controlled CPVT may do selected activities after careful assessment by an inherited arrhythmia specialist. Never begin exercise without a plan agreed with your cardiologist.

Is CPVT hereditary?

Yes. Most cases are caused by a variant in the RYR2 gene, which is passed on in an autosomal dominant way, giving each child a 50% chance of inheriting it. Some cases are recessive or arise as new mutations. All first-degree relatives should be offered testing.