When M
ichael underwent blood testing for the genetic defect, Long QT syndrome, Type 3 (LQT3), that caused his mother's cardiac arrest on February 23, 2006, he had a 50/50 chance that he had not inherited the same defect. Richard received the results of Michael's genetic testing this morning and it confirms that Michael has inherited the same defect.
We have been researching the consequences of this possibility for months, and are all prepared for what we have to do next as a family to insure Michael's health and well being, despite the gravity of the test results. As you can see from the picture Michael has been helping us with the research and we are confident that the future holds the promise for his health and happiness.
What is the QT Interval?
The QT is a time interval on an electrocardiogram tracing. The heart's natural pacemaker fires an electrical impulse to stimulate the heart to pump. The QT interval represents the electrical activity that passes through the heart muscle causing it to contract and pump blood through the heart. The QT interval continues until the end of the contraction when the heart muscle relaxes. The natural pacemaker then produces another electrical charge that stimulates the heart to pump again.
Long QT syndrome is a disturbance of the heart's electrical system. There are no physical abnormalities to detect on physical exam, only a subtle electrical disturbance on an EKG. Please note, 10-40% of long QT syndrome patients have a NORMAL QT interval on initial evaluation, so a normal QT does not exclude the condition. Long QT is caused by abnormalities of microscopic pores in the heart cells called ion channels. Ions such as potassium, sodium, calcium and chloride pass back and forth across the heart cells membranes through ion channels. As they do, they generate the electrical activity that controls the heart's beating. These electrical signals are detected on the surface of the body with electrodes and recorded by the electrocardiogram (EKG or ECG). Potassium and sodium ion channels are two of the sites affected in LQTS. The abnormal channels prolong the process of the electrical charge from the pacemaker passing through the heart muscle and therefore, lengthen the QT interval. This defect can cause the heart to beat abnormally leading to a cardiac arrest.
What are the symptoms of Long QT syndrome?
Sudden, temporary loss of consciousness (syncope) is the most common event. About ½ of LQTS patients NEVER experience syncope. Others have one or many syncopal events or cardiac arrest possibly resulting in sudden death. These events usually occur without warning. They are caused by a very fast cardiac arrhythmia known as torsade de pointes. Typically, the onset of symptoms is earlier in boys than in girls. Events may occur in the twenties, not so often in the thirties, and rarely past 40 years of age.
In patients who experience syncope only, the torsade de pointes rhythm spontaneously returns to normal, usually within about one minute, and the patient quickly regains consciousness, without disorientation or confusion. Some patients experience fatigue afterwards, others feel fine and resume their regular activities. On the other hand, in a minority of patients, the torsade de pointes rhythm persists then degenerates into the heart rhythm known as ventricular fibrillation, which rarely reverts back to a normal rhythm without medical intervention. If the ventricular fibrillation is not converted, usually by electrical defibrillation, the outcome is death.
There are many subtypes of LQTS and all but one involves an abnormality in the potassium channels. Long QT Syndrome type 3 is the only one to involve the sodium channels. In these subtypes, syncope often without warning symptoms, occurs during or just after physical exertion, emotional excitement, or sudden auditory arousal (such as a doorbell or alarm clock) but may occur in sleep or at rest. Conversely, in a simple faint (known medically as a vasovagal event) is primarily due to a fall in blood pressure accompanied by a slowing of the heart rate caused by pain, injury, nausea or stress. There are warning symptoms to fainting such as dizziness, blurring or blackening of vision, tingling or sweating, for seconds to even minutes prior to the syncope. In LQTS type 3, there are rarely any warning symptoms and the event occurs during sleep or at rest and is usually catastrophic.
Michael had his first appointment with his cardiac specialist, a pediatric cardiac electro physiologist, Dr. Sampson, before he was 2 months old and his follow-up appointment was when he was 6 months old. He had no abnormalities that showed on his EKG's at either visit, which was very encouraging, but the gold standard of his own genetic test has indeed identified the inherited abnormality. Michael has been on daily medication to prevent abnormal heart rhythm; since Lisa's genetic testing came back showing LQTS type 3. Michael has never shown any symptoms, but then neither had Lisa. Now that Michael is known to have the defect he will be examined again tomorrow by Dr. Sampson and another EKG will be done. His medication will be changed to one that is specific to his abnormality and a treatment plan will be established. All children without symptoms should be treated because some will become symptomatic and sudden death may be the first symptom. At present, it is not possible to tell which child is destined to have symptoms.
How can Michael be Protected?
** No medication misses!! Treatment for LQTS is effective in most instances by administration of daily medications.
**See doctor regularly for follow-up, even more often during periods of rapid growth. Growing children need medication dose changes regularly.
**Be supportive when the doctor advises "no competitive sports for Michael". Usual physical activities are suitable but competition can be dangerous.
**Channel Michael's energies into sports without intense physical demands (golf, for example) or non-physical activities.
**Have Michael avoid caffeine and over-the-counter stimulants (cold pills).
**Keep abreast of new research and treatment options and be proactive with the medical team.
**Hugs and kisses and Love, Love, Love
Addendum:
I have agonized over not having been able to save Lisa's quality of life when Richard and I fought to keep her alive on the night of her arrest. But, Lisa's grit and determination as she struggles through her rehabilitation has given Michael the greatest gift a mother can give. Michael will forever be protected with the knowledge that Lisa was able to give him with her genetic test results, which literally hold the promise of saving his life. A mother couldn't be more proud.
Sherry Wintory
– mlwintory@msn.com
