Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT)

Overview

Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited cardiac channelopathy in which physical exertion or acute emotion provokes ventricular arrhythmias. The heart is usually structurally normal and the resting electrocardiogram (ECG) is often normal. During adrenergic stress, ventricular ectopy may progress to bidirectional or polymorphic ventricular tachycardia (VT), ventricular fibrillation and sudden cardiac death.¹

CPVT commonly presents during childhood or adolescence, although onset in adulthood is recognised. The characteristic history is exertional or emotion-triggered syncope, seizure-like activity or cardiac arrest. Misdiagnosis as vasovagal syncope or epilepsy is common because routine examination, resting ECG and echocardiography may be unremarkable.²

CPVT is treatable but potentially lethal. Prompt recognition, exercise-based assessment, family screening and lifelong treatment are essential.

Anatomy & Physiology

Cardiac contraction depends on tightly regulated movement of calcium between the cardiomyocyte cytoplasm and the sarcoplasmic reticulum.

During each action potential:

1. Calcium enters the cardiomyocyte through L-type calcium channels.
2. This activates cardiac ryanodine receptor type 2 channels (RyR2) in the sarcoplasmic reticulum.
3. RyR2 releases a larger amount of stored calcium into the cytoplasm.
4. Cytoplasmic calcium binds to the contractile apparatus and produces contraction.
5. Calcium is subsequently returned to the sarcoplasmic reticulum, where it is stored partly through binding to calsequestrin-2.

Adrenergic stimulation during exercise or emotion increases heart rate, calcium entry and sarcoplasmic-reticulum calcium loading. In a healthy heart this produces a stronger, faster contraction without spontaneous calcium release.

Aetiology & Risk Factors

Aetiology

CPVT is most commonly caused by pathogenic variants affecting proteins responsible for intracellular calcium handling.^2,4

Gene	Usual inheritance	Functional effect
RYR2	Autosomal dominant	Abnormal cardiac ryanodine-receptor function and inappropriate calcium release
CASQ2	Usually autosomal recessive	Impaired calcium storage within the sarcoplasmic reticulum
CALM1, CALM2 and CALM3	Usually autosomal dominant	Abnormal calmodulin-dependent regulation of calcium handling
TRDN	Autosomal recessive	Abnormal triadin function and sarcoplasmic-reticulum calcium regulation
TECRL	Autosomal recessive	Overlapping CPVT and long-QT-like phenotype

A pathogenic variant is not identified in every clinically diagnosed patient. Conversely, an uncertain genetic variant does not establish CPVT without compatible clinical and phenotypic evidence.

Risk Factors

• Strenuous physical exercise
• Sudden bursts of exertion
• Acute emotional stress, fear or excitement
• Poor adherence to medication
• Inadequate beta-blocker dosing
• Use of sympathomimetic drugs or stimulants
• Failure to recognise affected relatives
• Previous cardiac arrest
• Recurrent syncope or ventricular arrhythmia despite treatment

Pathophysiology

Pathogenic variants affecting RyR2 or its regulatory proteins destabilise calcium handling within the sarcoplasmic reticulum.

During adrenergic stimulation:

1. Intracellular cyclic AMP and protein-kinase activity increase.
2. Sarcoplasmic-reticulum calcium loading rises.
3. Abnormal channels release calcium spontaneously during diastole.
4. The sodium–calcium exchanger removes excess intracellular calcium in exchange for sodium.
5. This produces a transient inward current and a delayed afterdepolarisation.
6. If the afterdepolarisation reaches threshold, it triggers a premature ventricular complex.
7. Repeated triggered beats progress from isolated ectopy to bigeminy, couplets, bidirectional VT and polymorphic VT.

This explains why the resting ECG can appear normal: the electrical instability becomes apparent when adrenergic stimulation increases intracellular calcium loading.

Clinical Manifestations

Typical Presentation

The classic presentation is syncope during:

• Running, swimming or competitive sport
• Sudden exertion
• Acute fear, anger or excitement
• Emotional stress

Other presentations include:

• Palpitations
• Presyncope
• Seizure-like movements caused by cerebral hypoperfusion
• Aborted sudden cardiac arrest
• Sudden unexplained death
• Detection during family screening

Symptoms often begin in childhood or adolescence. Adult presentations occur and should not be dismissed solely because of age.²

Clinical Clues

• Exertional or emotion-triggered syncope
• Recurrent “seizures” with normal neurological investigations
• Syncope while swimming
• A family history of exertional syncope, unexplained drowning or sudden death
• A structurally normal heart despite a serious ventricular arrhythmia
• A normal resting QT interval
• Exercise-induced ventricular ectopy that becomes progressively more complex as heart rate rises

Arrhythmia Pattern

During exercise, the ECG may show a characteristic progression:

• Isolated premature ventricular complexes
• Ventricular bigeminy
• Couplets
• Bidirectional VT
• Polymorphic VT
• Ventricular fibrillation

Arrhythmia commonly reduces as the heart rate falls during recovery.

Diagnosis

CPVT is diagnosed from the combination of a compatible clinical history and adrenergically induced ventricular arrhythmia in the absence of structural heart disease or another explanation. International consensus criteria recognise CPVT when an otherwise unexplained exercise- or catecholamine-induced bidirectional or polymorphic VT occurs in a structurally normal heart with a normal resting ECG. A pathogenic variant in an established CPVT-associated gene can also establish the diagnosis in an appropriate setting.³

Resting ECG

The resting 12-lead ECG is usually normal and is primarily used to identify alternatives such as:

• Long QT syndrome
• Brugada syndrome
• Pre-excitation
• Conduction disease
• Baseline ventricular ectopy
• Andersen–Tawil syndrome features, including prominent U waves

Sinus bradycardia may occur but is not diagnostic. A normal resting ECG does not exclude CPVT.

Exercise Stress Test

A symptom-limited exercise ECG is the principal diagnostic investigation in a patient able to exercise.

• Heart rate at the onset of ventricular ectopy
• Increasing ectopic burden as workload rises
• Progression from isolated premature ventricular complexes to bigeminy, couplets or VT
• Bidirectional or polymorphic morphology
• Reproduction of symptoms
• Reduction of arrhythmia during recovery

The test should be undertaken in an appropriately supervised environment with resuscitation facilities.

A positive test with the characteristic phenotype strongly supports CPVT. A negative test does not reliably exclude it, particularly when the history or family genotype is compelling. Repeat testing or a specialist modified exercise protocol may be appropriate when suspicion remains high.²

Exercise testing is also used after diagnosis to:

• Assess response to beta-blockade and flecainide
• Identify breakthrough ventricular ectopy
• Guide medication titration
• Support individualised advice about physical activity

Other investigations

• Ambulatory ECG Monitoring
• Cardiac Imaging: Echocardiography should confirm normal cardiac structure and ventricular function and exclude structural causes of ventricular arrhythmia.
• Pharmacological Adrenergic Challenge: Intravenous adrenaline or another catecholamine challenge may be considered in an expert setting when exercise testing is not feasible.
• Genetic Testing

Important Differentials

Differential	Distinguishing features
Vasovagal syncope	Usually associated with prolonged standing, heat or prodromal nausea; not accompanied by exercise-induced ventricular arrhythmia
Epilepsy	Events may occur without exertional triggers; arrhythmic syncope may produce convulsive movements
Long QT syndrome	Prolonged or abnormal QT phenotype, genotype-specific triggers and torsades de pointes rather than typical bidirectional VT
Andersen–Tawil syndrome	Ventricular arrhythmia with periodic paralysis and characteristic facial or skeletal features; prominent U waves may be present
Digoxin toxicity	Medication exposure, gastrointestinal or neurological features and characteristic ECG abnormalities; may also produce bidirectional VT
Arrhythmogenic cardiomyopathy	Structural or tissue abnormalities, characteristic ECG findings and ventricular arrhythmias often arising from a consistent ventricular origin
Myocarditis	Acute systemic illness, chest pain, troponin elevation and myocardial abnormalities on imaging
Anomalous coronary artery	Exertional symptoms with an anatomical coronary abnormality rather than a primary calcium-handling disorder

Genetics & Family Screening

Once a pathogenic or likely pathogenic familial variant is identified, first-degree relatives should be offered targeted cascade testing. Relatives who carry the variant require clinical assessment even if they are asymptomatic.⁴

When no causative variant is identified, first-degree relatives should undergo clinical screening that generally includes:

• Detailed personal and family history
• Resting ECG
• Exercise stress testing
• Additional ambulatory monitoring when clinically indicated

A single normal exercise test may not completely exclude disease in a genotype-positive relative or a person with a compelling family history. Follow-up should be directed by an inherited-arrhythmia service.

Genetic counselling should address:

• Autosomal dominant and autosomal recessive inheritance
• Variable penetrance and clinical severity
• De novo variants
• Implications for siblings, parents and children
• Reproductive options
• The limitations of variants of uncertain significance

Treatment

Management aims to prevent adrenergically induced ventricular arrhythmia while allowing safe, sustainable daily activity.

Lifestyle and Trigger Management

• Avoiding competitive sport and strenuous exercise
• Avoiding sudden bursts of intense activity
• Reducing exposure to extreme emotional stress where practicable
• Avoiding sympathomimetic stimulants and recreational drugs
• Checking over-the-counter cold, flu and weight-loss preparations
• Maintaining strict medication adherence
• Developing an emergency plan for schools, workplaces and sporting environments

Exercise advice should be individualised using treatment response, exercise-test findings and shared decision-making with an inherited-arrhythmia specialist.¹

Beta-Blockers

A non-selective beta-blocker without intrinsic sympathomimetic activity is first-line therapy. Nadolol is generally preferred when available; propranolol is an alternative.^1,2

Flecainide

Flecainide is added when ventricular arrhythmia persists during exercise despite an adequately dosed beta-blocker. It may also reduce recurrent arrhythmia and ICD shocks.¹

Flecainide is usually used with, rather than instead of, beta-blockade. Follow-up should assess ECG intervals, medication tolerance and exercise-induced arrhythmia.

Left Cardiac Sympathetic Denervation

Left cardiac sympathetic denervation reduces adrenergic input to the heart and may be considered when ventricular arrhythmia persists despite maximally tolerated beta-blocker and flecainide, medication is not tolerated, recurrent appropriate ICD shocks occur, or an ICD is unsuitable or cannot provide adequate control.

Denervation reduces risk but does not necessarily eliminate the need for medication.

Implantable Cardioverter-Defibrillator

An ICD may be indicated after cardiac arrest or in patients with recurrent syncope or sustained ventricular arrhythmia despite optimal medical therapy.¹

• A painful shock may trigger further catecholamine release
• This may intensify ventricular arrhythmia and produce an electrical storm
• Shocks may be ineffective against some bidirectional or polymorphic episodes
• Inappropriate shocks may occur
• Device complications are especially important in young patients

An ICD should not be used as a substitute for beta-blockade, flecainide, trigger control or consideration of sympathetic denervation. Device programming should be directed by an electrophysiologist experienced in inherited arrhythmia syndromes.

Complications & Prognosis

Complications

• Recurrent exertional syncope
• Traumatic injury during syncope
• Seizure-like episodes and misdiagnosis as epilepsy
• Sustained bidirectional or polymorphic VT
• Ventricular fibrillation
• Sudden cardiac arrest or death
• Recurrent ICD shocks
• Electrical storm
• Psychological distress and activity restriction
• Device- and procedure-related complications

Prognosis

Untreated CPVT carries a substantial risk of recurrent syncope, cardiac arrest and sudden death.² Outcomes improve considerably with early diagnosis, strict adherence to non-selective beta-blockade, addition of flecainide when required, trigger modification and specialist follow-up.¹

Higher-risk clinical features include:

• Previous cardiac arrest
• Diagnosis at a younger age
• Exercise-induced complex ventricular arrhythmia
• Recurrent syncope during treatment
• Persistent arrhythmia despite adequate therapy
• Poor medication adherence
• Failure to restrict unsafe high-intensity activity

Breakthrough events frequently reflect missed medication or inadequate dosing. Regular review should therefore include adherence, interval symptoms, exercise-test response, growth-related dose adjustment and screening of relatives.

References

1. Zeppenfeld K, Tfelt-Hansen J, de Riva M, Winkel BG, Behr ER, Blom NA, et al. 2022 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. Eur Heart J. 2022;43(40):3997–4126. doi:10.1093/eurheartj/ehac262.
2. Napolitano C, Mazzanti A, Bloise R, Priori SG. Catecholaminergic polymorphic ventricular tachycardia. In: Adam MP, Feldman J, Mirzaa GM, Pagon RA, Wallace SE, Amemiya A, editors. GeneReviews® [Internet]. Seattle: University of Washington, Seattle; 2004 [updated 2022 Jun 23; cited 2026 Aug 26]. Available from: https://www.ncbi.nlm.nih.gov/books/NBK1289/
3. Priori SG, Wilde AA, Horie M, Cho Y, Behr ER, Berul C, et al. HRS/EHRA/APHRS expert consensus statement on the diagnosis and management of patients with inherited primary arrhythmia syndromes. Heart Rhythm. 2013;10(12):1932–1963. doi:10.1016/j.hrthm.2013.05.014.
4. Wilde AAM, Semsarian C, Márquez MF, Sepehri Shamloo A, Ackerman MJ, Ashley EA, et al. European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on the state of genetic testing for cardiac diseases. Europace. 2022;24(8):1307–1367. doi:10.1093/europace/euac030.
5. Femenia F, Barbosa-Barros R, Sampaio SV, Arce M, Perez-Riera A, Baranchuk A. Bidirectional ventricular tachycardia: a hallmark of catecholaminergic polymorphic ventricular tachycardia. Indian Pacing Electrophysiol J. 2012;12(2):65–68.