page_title: Catecholaminergic polymorphic ventricular tachycardia
section_title: Signs and symptoms
hierarchical_section_title: Catecholaminergic polymorphic ventricular tachycardia / Signs and symptoms
caption_attribution_description: English: Abnormal heart rhythms in a case of CPVT. The patient, a 13 year old girl, presented with a history of fainting during exercise.
context_page_description: Catecholaminergic polymorphic ventricular tachycardia is an inherited genetic disorder that predisposes those affected to potentially life-threatening abnormal heart rhythms or arrhythmias. The arrhythmias seen in CPVT typically occur during exercise or at times of emotional stress, and classically take the form of bidirectional ventricular tachycardia or ventricular fibrillation. Those affected may be asymptomatic, but they may also experience blackouts or even sudden cardiac death.
  CPVT is caused by genetic mutations affecting proteins that regulate the concentrations of calcium within cardiac muscle cells. The most commonly identified gene is RYR2, which encodes a protein included in an ion channel known as the ryanodine receptor; this channel releases calcium from a cell's internal calcium store, the sarcoplasmic reticulum, during every heartbeat.
  CPVT is often diagnosed from an ECG recorded during an exercise tolerance test, but it may also be diagnosed with a genetic test. The condition is treated with medication including beta-adrenoceptor blockers or flecainide, or with surgical procedures including sympathetic denervation and implantation of a defibrillator.
context_section_description: Although individuals with CPVT may not experience any symptoms, the most commonly reported symptoms are blackouts or sudden loss of consciousness, referred to as syncope. These blackouts often occur during exercise or as a response to emotional stress—situations in which chemical messengers known as catecholamines, such as adrenaline, are released within the body. Blackouts may be misinterpreted as being caused by simple faints or epilepsy, often leading to delays in reaching the correct diagnosis. In a third of those affected, the first manifestation of the disease may be cardiac arrest, potentially leading to sudden death. This can occur in very young children, presenting as sudden infant death syndrome or 'cot death'. Approximately 30% of those with CPVT will have a family member who has experienced blackouts, seizures, or sudden death in response to exercise or stress.
  In those with CPVT, catecholamine release can lead to an abnormal heart rhythm or arrhythmia known as ventricular tachycardia. The ventricular tachycardia may take a characteristic form known as bidirectional ventricular tachycardia. This form of ventricular tachycardia occurs relatively infrequently, but if seen is suggestive of an underlying diagnosis of CPVT or the related condition Andersen-Tawil syndrome. These ventricular arrhythmias in some cases terminate by themselves, causing a blackout from which the person then recovers. However, if the abnormal heart rhythm continues, it can degenerate into a more dangerous arrhythmia known as ventricular fibrillation causing a cardiac arrest and, if untreated, sudden death.
  There are typically very few abnormal signs on clinical examination in persons with CPVT. However, those with CPVT may develop a less serious heart rhythm disturbance called atrial fibrillation, which can be detected on examination as an irregular pulse. Furthermore, approximately 20% of those with CPVT have a slow resting heart rate known as a sinus bradycardia.
caption: Abnormal heart rhythms in a case of CPVT
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