Catecholaminergic polymorphic ventricular tachycardia(patient information)
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mounika Reddy Vadiyala, M.B.B.S.[2]
Overview
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare condition characterized by an irregular heart rhythm (arrhythmia) that can be life-threatening. In people with CPVT, these episodes typically begin in childhood but symptoms can also show up later in life. As the heart rate increases in response to physical activity or emotional stress, it can trigger an abnormally fast and irregular heartbeat called ventricular tachycardia. With this condition, the heart beats so quickly that it doesn't have enough time to fill blood between beats. As a result, not enough blood gets pumped to the body. The first sign is often fainting or near fainting during exercise or strong emotion. Other symptoms include light-headedness, dizziness, and also may cause the heart to stop beating (cardiac arrest), leading to sudden death. If untreated, it is very lethal.
What are the symptoms of catecholaminergic polymorphic ventricular tachycardia?
The symptoms typically start with ventricular tachycardia (VT) during physical activity or emotional stress:
- Fainting is commonly the first sign of the disease
- Light-headedness or dizziness
- Palpitations or unpleasant awareness of the heartbeat
Sometimes the ventricular tachycardia goes away, and symptoms stop. At times, ventricular tachycardia can turn into ventricular fibrillation (VF) in which the ventricles quiver and are unable to pump blood. This sudden loss of heart function leads to sudden cardiac arrest. A person stops breathing and becomes unresponsive. Unfortunately, sudden cardiac arrest is sometimes the first sign of CPVT. Sudden cardiac arrest can lead to sudden cardiac death.
What causes catecholaminergic polymorphic ventricular tachycardia?
- CPVT is caused by a gene defect (abnormal gene). Genes are part of your DNA, the material passed down from parents to children, which can be passed down through families and inherited in different ways (from either one or both parents).
- In some cases, CPVT is autosomal dominant which means you need an abnormal gene from only one of your parents to have it. In other cases, CPVT is autosomal recessive which means you need an abnormal gene from both of your parents to get the disease.
- CPVT can result from mutations in genes such as RYR2 and CASQ2. RYR2 gene mutations cause about half of all cases, while mutations in the CASQ2 gene account for 1 percent to 2 percent of cases.
- The RYR2 and CASQ2 genes provide instructions for making proteins that help maintain a regular heartbeat. For the heart to beat normally, heart muscle cells called myocytes must tense (contract) and relax in a coordinated way. Both the RYR2 and CASQ2 proteins are involved in handling calcium within myocytes, which is critical for the regular contraction of these cells.
- Mutations in either the RYR2 and CASQ2 gene disrupt the handling of calcium within myocytes. During exercise or emotional stress, impaired calcium regulation in the heart can lead to ventricular tachycardia in people with CPVT.
- Stress and exercise can trigger episodes. Certain medicines, such as catecholamines, can also make it worse.
Who is at highest risk?
Diagnosis
When to seek urgent medical care?
Go to the emergency room or call the local emergency number (such as 911) if you have a rapid, irregular pulse, faint, or have chest pain. All of these may be signs of ventricular tachycardia.