Long QT syndrome type 1

Recognizing signs of silent killer

It's 7a.m. A 28-year-old woman is wheeled into the emergency room. Her husband explains that she started to have what looked like a seizure when her alarm sounded for work. The young woman is assessed and found to be in stable condition with no apparent history of seizures or syncope. She explains that she gets dizzy during times of stress or exertion. The results of neurological consult are unremarkable.

In this scenario, the patient may be released witbout further diagnostic assessment, cardiac work up or follow up. In fact, she may be suffering from a poorly understood disorder called Long QT Syndrome (LQTS).

I'd like to share what I have learned about LQTS in the hope of reaching some of the front-line staff who may be responsible in assisting doctors during this type of patient scenario. Many cases of LQTS may be misdiagnosed or even missed altogether. The patient's first symptom may in fact be their very last.

LQTS is a disorder of the heart's electrical system, particularly the heart's ability to recharge after a heartbeat, better known as repolarization. The QT interval is a period of time measured by an ECG. The interval represents the period of time in which the heart needs to recharge or repolarize. When the QT interval is prolonged, the patient is vulnerable to ventricular arrhythmia, specifically torsade de point, represented as a sort of twisted helix on the ECG.

The incidence of the disorder is unknown and it is estimated that about one third of patients never develop any symptoms at all. The most common symptoms of LQTS include sudden toss of consciousness and death which tend to occur under physical stress or when startled. Current research suggests that six genes may be responsible for the disorder. A possible link of LQTS to Sudden Infant Death Syndrome is also being explored.

Treatment options include beta blockade therapy to slow conduction of the heart, implanting a pacemaker or internal cardiac defibrillator to override a possibly lethal arrhythmia. In cases such as asthmatics where beta blockade therapy is not recommended, a procedure called a left cervico-thoracic sympathectomy can be performed to remove the nerves that over-stimulate the heart.

Dr. G. Michael Vincent, a professor of medicine at the University of Utah founded the American Sudden Arrhythmia Death Syndrome (SADS) Foundation in 1991. He has been instrumental in forming a Canadian SADS group operating in Toronto. Dr. Vincent's extensive research on LQTS, his desire to educate health care professionals about his findings, to provide support and to increase public awareness of LQTS has no doubt saved many lives.

According to an article published in the 7bronto Star in 1994, Dr. Vincent lists three key points for health care professionals to keep in mind:

* Be aware of unexplained loss of consciousness in children and teens under times of physical exertion or stress.

* When a young person presents with these symptoms, suggest to the attending physician that an ECG be done with special attention to the QT interval.

* If a family member is identified as having LQTS, all members of the family and the extended family should be tested.

Not long after my diagnosis, the founder of the Canadian SADS foundation, Payn Kotsilitis, contacted me. Pam's son died suddenly at the age of 16. Greg had a history of loss of consciousness with startling, particularly when awakened by his alarm for his early-moming paper route. Unfortunately, Greg's last symptom was death.

In August 1999, several of us with varying experiences related to LQTS met in Edmonton to talk about establishing a western Canada chapter of the SADS foundation. The Canadian SADS Foundation in Toronto has been overwhelmingly supportive of our initiative. In October 1999, 1 attended the first annual Canadian SADS conference in Toronto featuring American and Canadian physicians speaking on all aspects of this syndrome. I hope to share what I learn and to support families affected by LQTS in Western Canada.

My encounter with LQTS

My experience with Long QT Syndrome began in October 1995 when my father died suddenly in his early 40s. His family doctor recommended that my siblings and I have a cardiac work up to ensure we did not have any unknown cardiac arrhythmias. In November, Dr. Timothy Prieur tested me on an exercise treadmill, noted a QT prolongation and subsequently referred me to electrophysiologists Dr. Robert Sheldon and Dr. Derek Exner.

In retrospect, there were warning signs during peak activity in my adolescence and stresSful situations such as nursing school. I would get flushed, hate a racing heart. and feel like I was going to faint, It generally subsided on its own when I rested. For Years I blamed hypoglycemia, but according to Dr Derek Exner, hypoglycemia is actually quite rare and often misdiagnosed. My, treatment options were simple. With absence of true syncope or seizures I was put on beta blockade therapy.

When I was diagnosed with LQTS in 1995, 1 was working in family practice. Since then, I have pursued an interest in cardiac nursing and I am currently practising in fix cardiac surgery ward at FoothilL Hospital.

References

SADS website @ www.sads.org. page 1 of "current news" by Dr.G. Michael Vincent AD.

SADS website @ www.sads.org. page 1-4 of "An Overview of the Inherited Long QT Syndrome" by Dr.G.Michael Vincent.

Toronto Star Oct. 10, 1994 by staff reporter Janice Dineen.

The Spectrum of symptoms and QT intervals in carriers of the gene for the Long QT syndrome. Article reprinted from the New England journal of Medicine 327:846-852 (September 17), 1992 authors: Dr.G. Michael Vincent M.D., Katherine W Timothy B.S., Mark Leppert, Ph.D.,and Mark Keating, M.D.

The Sudden infant Death Syndrome and LQ7N. is there a link? summer/fall SADS newsletter, 1999. By Dr. Peter Schwartz M.D. SADS scientific advisor Professor and Chairman Dept of Cardiology, University of Pavia. Pavia, Italy.

EX can provide confirmation of syndrome. Calgary Herald Aug. 27,1999 by staff reporter Susan Scott and Dr. Michael Giuffre M.D. Pediatric Cardiologist. Calgary, Alberta

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