Romano-Ward Syndrome. Long QT Syndrome.
Incidence
It is a genetic disorder that is inherited in an autosomal dominant pattern, usually from the parent who also has RWS. Romano-Ward syndrome was thought to occur in one out of every 5000 to 7000 babies born. However, as we learn more about the disease, some people now believe that RWS is much more common and may occur in one of every 3000 to 5000 people. In the United States, this disorder is thought to affect about 50,000 people. There seems to be no racial preference. Studies have shown that boys seem to have increased risk of cardiac events (syncope or death) until they reach puberty. After puberty, the girls tend to have an increased risk.
Clinical Characteristics
Romano-Ward syndrome (RWS), or long QT syndrome, is a genetic disorder that causes arrhythmias (abnormal heart beat rhythms). While the heart's rhythm is normal most of the time in this syndrome, people with long QT syndrome are at risk for sudden arrhythmias that can cause loss of consciousness (syncope) or death. It can be identified before the arrhythmias occur by changes on an EKG. The usual symptoms are syncope or sudden death, which typically occur during times of emotional stress or physical activity. Some individuals may also have an abnormally slow resting heart rate. These symptoms can present at any age, from a newborn baby to an adult, but most commonly they begin in the teenage years. Sometimes, a seizure is blamed for the original loss of consciousness, and the RWS will remain undiagnosed. Any sudden loss of consciousness during physical activity or during a time of emotional stress should raise suspicion for the Romano-Ward syndrome and physicians should obtain an EKG to look for a prolonged QT interval. The inciting events, or triggers, for these cardiac events can be broken down into: physical activity (swimming or running), loud noises (alarm clock, horn or ringing phone), or emotions (anger, crying, taking an exam or other stressful situations). Sudden death may also occur when a person is sleeping. So far, there have been five genes discovered that have mutations that cause the long QT syndrome, but there are probably several more that have not been located yet. These genes code for proteins that make up the gates that trigger the heart muscle to contract. These gates, or cardiac ion channels, allow positive and negative charges to move in and out of the heart muscle. In RWS, the faulty gates allow too many positive charges to enter into the heart muscle. When this happens, the heart muscle has a little too much relaxing time before the next heart beat. It is during this extra time that the heart is vulnerable and can be stimulated by one of the above triggers to start into a rapid heartbeat. Most of the time this rapid heart beat stops by itself, but sometimes it can continue on into the arrhythmias that lead to syncope or sudden death.
Precipitants
The inciting events, or triggers, for these cardiac events can be broken down into: physical activity (swimming or running), loud noises (alarm clock, horn or ringing phone), or emotions (anger, crying, taking an exam or other stressful situations).
Provocation Tests
None should be attempted.
Diagnostic Procedures
A simple EKG can make the diagnosis, though occasionally other tests are needed. The QT interval varies with age and sex. If a family member is known to have the disorder and their specific mutation is known, sometimes it is possible to check blood samples for the same gene mutation.