Catecholaminergic Polymorphic Ventricular Tachycardia
Catecholaminergic polymorphic ventricular tachycardia or CPVT is a rare inherited condition that results in abnormal heart rhythms occurring with exercise or activities associated with high adrenaline levels. These abnormal rhythms are absent at rest but can cause syncope (fainting) or even sudden cardiac death with physical exertion or emotional stress. CPVT can present at any age but symptoms generally begin in childhood.
CPVT is not associated with abnormal heart structure so cardiac imaging studies are usually normal. Resting EKGs are also normal since the abnormal heart rhythms only occur with exercise. CPVT is diagnosed by cardiac stress (treadmill) test and typical findings include polymorphic ventricular tachycardia (fast abnormal heart rhythm).
Medications reduce the risk for syncope and sudden death in individuals with CPVT. Most of the time CPVT can be effectively treated with medication but if a person continues to have symptoms while taking medication, an internal cardioverter defibrillator (ICD) might be recommended.
Genetics
The abnormal heart rhythms in CPVT are due to genetic differences in the electrical system that controls the heart rhythm. So far, a couple genes have been associated with CPVT and mutations in these genes are responsible for over half of families with the condition. We expect to identify more genes responsible for CPVT as our knowledge in cardiac genetics improves over time.
Most commonly, CPVT is inherited in an autosomal dominant manner. This means that each child of a parent with CPVT has a 50% chance of inheriting the genetic mutation associated with the condition. The chance of inheriting the mutation is the same for men and women. There is a far less common form of CPVT that follows an autosomal recessive inheritance pattern. In this pattern, CPVT is due to two gene mutations, one that has been inherited from each parent. The siblings of an individual with autosomal recessive CPVT each have a 25% chance of having the condition.
Some people who inherit the genetic mutation never have any health problems related to CPVT. However, they can still pass the mutation to their children who may develop abnormal heart rhythms.
Genetic testing can be done to try to identify the genetic mutation causing CPVT to confirm the diagnosis and so other family members can have genetic testing to determine their risk for abnormal heart rhythms associated with the condition.
Family members
Since CPVT is a genetic condition, the family members of someone who has the condition may be at risk of developing the abnormal heart rhythms. Close relatives (parents, siblings, and children) of someone with CPVT should be evaluated for the condition by consulting a cardiologist familiar with CPVT or having genetic testing if the gene mutation associated with the condition in the family has been found.
Electrophysiologists are cardiologists who are experts in abnormal heart rhythms. Appointments can be made with the electrophysiologists at UCSF by calling (415) 353-2873.
Precautions
Individual recommendations should be made with the help of a cardiologist. However, individuals with CPVT may be advised to avoid strenuous exercise since exertion can provoke dangerous heart rhythms.
Resources for support and information:
Research
Comprehensive Genetic Arrhythmia Program
Primary Investigator: Melvin Scheinman, MD