Dr. Alessandro Giardini
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Catecholaminergic polymorphic ventricular tachycardia, almost always referred to simply as CPVT, is a rare but serious inherited heart rhythm condition that typically comes to light during childhood or early adolescence. The name may be daunting, but the underlying idea is fairly straightforward: in children with CPVT, the heart beats normally at rest, yet can develop a dangerously fast and chaotic rhythm when the body releases adrenaline, for example during physical exercise or a moment of intense emotion. Understanding what CPVT is, how it is recognised, and how it can be managed effectively is the first and most important step for any family facing this diagnosis.
The heart relies on a precisely timed electrical system to pump blood efficiently. Each heartbeat is triggered by an electrical signal that travels through the heart muscle in an orderly sequence. In children with CPVT, a fault in the way the heart muscle cells handle calcium (an essential chemical messenger inside every cell) disrupts this electrical order at moments of high adrenaline. The result is an abnormal heart rhythm called ventricular tachycardia, in which the lower chambers of the heart beat far too fast and in a disorganised pattern.
CPVT affects approximately 1 in 10,000 people and is considered one of the most important causes of unexplained cardiac arrest and sudden death in young people who otherwise appear completely well. Crucially, the resting ECG is usually normal, the heart looks structurally normal on an echocardiogram, and there may be no symptoms whatsoever between episodes. This is what makes CPVT both treacherous and, in the right hands, manageable once identified.
The condition most commonly presents between the ages of 7 and 12, though it can come to light at any point from infancy through to adulthood.
CPVT is caused by a fault in one of the genes responsible for regulating the release and reabsorption of calcium within heart muscle cells. In a healthy heart, calcium is released in precise, controlled pulses to trigger each contraction. In CPVT, this regulation is impaired, and when adrenaline surges through the body, calcium leaks out of its storage compartment in an uncontrolled way, sparking abnormal electrical activity.
The most commonly affected gene is RYR2, which encodes the cardiac ryanodine receptor, essentially the gatekeeper that controls calcium release. Mutations in RYR2 account for approximately 60% of CPVT cases and follow an autosomal dominant pattern of inheritance, meaning a child only needs to inherit one faulty copy to be affected. The second most common genetic cause involves the CASQ2 gene, encoding calsequestrin 2, a protein that stores calcium within the cell. CASQ2 mutations account for around 2–5% of cases and follow an autosomal recessive pattern, meaning a child must inherit one faulty copy from each parent to develop the condition. Rarer causes include variants in the genes CALM1, TRDN, and TECRL, all of which affect related aspects of calcium handling.
In around 30–40% of children with a clinical diagnosis of CPVT, no causative gene mutation is found with current testing panels. The absence of a positive genetic result does not invalidate the diagnosis and does not remove the need for treatment.
The hallmark of CPVT is symptoms that are triggered by exercise or strong emotion and that resolve when the child calms down or stops exercising. This pattern is distinctive and should always prompt further investigation when it is reported.
The most common symptoms include fainting (syncope), which may be sudden and without warning, dizziness or light-headedness during exertion, a sensation of the heart racing or pounding (palpitations), and, in the most serious presentations, cardiac arrest. Some children describe feeling briefly unwell or dizzy during PE, competitive sport, or a moment of fright or excitement. Others have no symptoms at all and are only identified because a family member has been diagnosed.
It is important to recognise that a faint during exercise, or a faint accompanied by a seizure-like episode, should always be assessed by a cardiologist. These presentations are sometimes incorrectly attributed to epilepsy or a simple faint, and the distinction matters enormously. Dr Giardini assesses all children with exertional or emotion-triggered syncope carefully, because early diagnosis of conditions like CPVT is directly life-saving.
Between episodes, children with CPVT look and feel entirely normal. There is no murmur, no breathlessness at rest, and no visible sign of a heart problem. This normality between events is one of the reasons a high index of clinical suspicion is so important.
Because the heart appears normal at rest, diagnosing CPVT requires tests designed to provoke or detect the abnormal rhythm under controlled conditions.
The most important investigation is an exercise stress test, typically performed on a treadmill. As the child's heart rate rises and adrenaline levels increase, characteristic abnormal heartbeats appear on the ECG monitor: a pattern of bidirectional or polymorphic ventricular tachycardia that is specific enough to confirm the diagnosis in the right clinical setting. The exercise test is performed under close medical supervision with resuscitation equipment immediately available.
An echocardiogram (cardiac ultrasound) is performed in all children to confirm that the heart's structure is entirely normal, a key feature of CPVT that distinguishes it from other conditions. The resting ECG is also obtained, though it is typically normal and is used primarily to exclude other conditions such as long QT syndrome. Ambulatory ECG monitoring (a Holter monitor worn for 24–48 hours, or longer) may capture spontaneous arrhythmias during everyday activities, particularly in younger children who cannot reliably complete a formal exercise test.
Genetic testing forms an essential part of the diagnostic work-up. A blood or saliva sample is analysed for mutations in the key CPVT genes, beginning with RYR2 and CASQ2. A positive result confirms the genetic cause, guides family screening, and has some implications for predicting inheritance patterns. A negative result does not rule out CPVT if the clinical picture is convincing.
In selected cases, particularly where the exercise test is inconclusive or the child is too young to perform it, adrenaline (epinephrine) provocation testing can be performed in hospital to elicit the abnormal rhythm safely. This is always carried out by an experienced paediatric electrophysiologist in a monitored setting.
CPVT cannot be cured, but with the right treatment it can be managed very effectively, and the risk of life-threatening events can be reduced substantially. Treatment is lifelong and requires ongoing specialist follow-up, but the large majority of children with CPVT go on to live full and rewarding lives.
Beta-blockers are the cornerstone of treatment. These medications block the effect of adrenaline on the heart, directly addressing the trigger mechanism for arrhythmias in CPVT. Non-selective beta-blockers, particularly nadolol and propranolol, are preferred because they block both types of adrenaline receptor more completely. It is essential that children with CPVT take their beta-blocker every day without missing doses, as even a single missed tablet can leave them unprotected. The medication must never be stopped suddenly.
Flecainide is an antiarrhythmic medication that has emerged as a highly effective addition to beta-blocker therapy in children whose arrhythmias are not fully suppressed on beta-blockers alone. Recent large-scale studies have confirmed that adding flecainide reduces arrhythmic events by more than 50% in patients who continue to have breakthroughs on beta-blocker therapy.
Exercise restriction is a necessary part of managing CPVT. High-intensity competitive sport is generally not recommended, because it generates the sustained adrenaline surges most likely to provoke dangerous arrhythmias. However, the degree of restriction is individualised based on the child's response to treatment, and the goal is always to allow the maximum amount of safe physical activity. Many children with well-controlled CPVT can enjoy recreational exercise, swimming, and moderate physical activity. Decisions about sport are made collaboratively, taking the child's and family's wishes fully into account.
Left cardiac sympathetic denervation (LCSD) is a surgical procedure in which the nerves that carry adrenaline signals to the heart are interrupted on the left side of the chest. It is a highly effective treatment for children who continue to have arrhythmias despite optimal medical therapy and represents an important alternative to an ICD in many cases. The procedure is performed via a minimally invasive approach and has an excellent safety record in specialist centres.
An implantable cardioverter-defibrillator (ICD) delivers a life-saving electric shock if a dangerous arrhythmia occurs. In CPVT, ICD implantation requires careful consideration because an ICD shock itself causes pain and distress, which triggers further adrenaline release potentially creating an electrical storm with repeated shocks. For this reason, ICDs in CPVT are used selectively, usually after a cardiac arrest or in children with high-risk features that have not responded adequately to medication and LCSD. When an ICD is implanted, it is combined with optimised medical therapy, never used as a standalone treatment.
Emergency preparedness is an integral part of care for every child with CPVT. Families are advised on how to perform CPR, encouraged to ensure that school staff are aware of the diagnosis, and in some cases provided with a home automated external defibrillator (AED). Every child with CPVT should have a clear written emergency plan accessible to parents, school, and sports clubs.
Because CPVT is inherited, a diagnosis in one family member has direct implications for everyone else in the family. All first-degree relatives parents, brothers and sisters, and children of an affected individual should be offered cardiac screening and, where a genetic mutation has been identified, genetic testing.
For RYR2-related CPVT (the most common form), inheritance is autosomal dominant: each child of an affected parent has a 50% chance of inheriting the mutation. For CASQ2-related CPVT, inheritance is autosomal recessive, which means both parents carry one copy of the mutation without being affected themselves, and each child has a 25% chance of developing the condition.
Screening of relatives involves an ECG, an echocardiogram, and an exercise stress test. Where a mutation has been confirmed in the index case, relatives who test negative for that specific mutation can be reassured and discharged from cardiac surveillance. Relatives who test positive for the mutation require the same comprehensive evaluation and should be followed up regularly, even if no arrhythmias are detected initially. In children of an affected parent, screening is recommended from the age of around 8 or earlier if symptoms are present or the family history is particularly severe.
Genetic counselling is strongly recommended for all families with a confirmed CPVT diagnosis. A genetic counsellor can explain the inheritance pattern in plain terms, discuss implications for future pregnancies if relevant, and help the family decide who else in the wider family tree should be evaluated. Dr Giardini works closely with dedicated inherited cardiac conditions and genetics teams to ensure every family receives coordinated, holistic support from the point of diagnosis onwards.
If you have a family history of unexplained fainting during exercise, seizures during sport, or sudden cardiac death in a young person, please do not wait for symptoms to occur before seeking specialist review.
Without treatment, CPVT carries a significant risk of dangerous arrhythmias that can lead to cardiac arrest. With appropriate diagnosis and treatment, including beta-blockers and lifestyle adjustments, the risk of serious events is greatly reduced. The earlier CPVT is identified and treated, the better the outcome.
Yes, most children with CPVT can live full and active lives. Treatment focuses on reducing arrhythmia risk while maximising quality of life. While high-intensity competitive sport is generally avoided, many children enjoy recreational activities, school, and social life without significant restriction. Regular specialist follow-up ensures that treatment remains optimised as the child grows.
In CPVT, the heart's electrical activity at rest is completely normal. The characteristic abnormal rhythm only appears when adrenaline levels rise, which is why an exercise stress test is the key diagnostic investigation rather than a resting ECG.
Fainting during exercise, particularly if it is sudden and unexplained, always warrants urgent cardiac assessment. While most exercise-related faints have a benign cause, a proportion are the first presentation of a serious underlying condition such as CPVT. Any child who faints or collapses during physical activity should be reviewed by a paediatric cardiologist before returning to sport.
Yes. The most common form of CPVT is inherited in an autosomal dominant pattern, meaning a parent who carries the mutation has a 50% chance of passing it to each child. This is why all first-degree relatives of someone with CPVT should be screened, even if they feel entirely well.
No. An ICD is not the right treatment for every child with CPVT, and in this condition ICDs require particularly careful consideration because a shock can trigger further adrenaline release. Many children are very well protected on medication alone, or with the addition of a surgical procedure called left cardiac sympathetic denervation. The decision is always made on an individual basis with a specialist team.
No. Beta-blockers for CPVT must be taken every single day without breaks. The medication does not cure the condition but it continuously suppresses the trigger mechanism. Stopping it, even briefly, removes this protection and can be very dangerous. It should never be stopped suddenly without discussion with the cardiologist.
Symptoms most commonly appear between the ages of 7 and 12, though CPVT can present in infancy or remain unrecognised until adulthood. The median age of onset in published studies is approximately 10 years. Children with a family history of CPVT should be screened proactively rather than waiting for symptoms to develop.
Author: Dr. Alessandro Giardini, MD, PhD
Written 30/03/2026