Mayo Clinic researchers published a study Monday that offers new hope for patients suffering from long QT syndrome , a potentially-fatal heart rhythm condition.
Sudden cardiac death and episodes of fainting and seizures are significantly lower than previously thought when patients are diagnosed and treated at a speciality center dedicated to the treatment of genetic heart rhythm diseases, according to the 16-year study just published in the Journal of the American College of Cardiology.
The study tracked 606 patients with long QT syndrome at Mayo Clinic's Genetic Heart Rhythm Clinic from January 1999 to December 2015. Mayo says patients' health records were analyzed to note how many experienced symptoms or died despite receiving treatment. It's one of the largest studies ever conducted on long QT syndrome.
According to the study, 92 percent of patients did not experience symptoms after treatment and the overall chance of sudden cardiac death was deemed low.
"Although long QT syndrome is a potentially lethal syndrome, when it is recognized and treated, sudden death should almost never happen," said senior author Dr. Michael Ackerman, director of Mayo Clinic's Long QT Syndrome/Genetic Heart Rhythm Clinic in Rochester. "The expectation needs to shift from merely preventing sudden death to enabling these patients and their families to live and thrive despite the diagnosis. Hopefully, the results of this study should be reassuring and encouraging to these families who live with long QT syndrome."
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Researchers found that only 50 patients experienced breakthrough cardiac events, despite "comparatively lower use of implantable defibrillators and a philosophy of shared decision-making that enables patients to remain active." Of those 50 patients, just two experienced sudden cardiac death and three other required a heart transplant.
Existing estimates suggest that long QT syndrome occurs in only 1 in 2,000 people, though it's one of the common causes of sudden cardiac death.
"Because the disease is so rare, it is challenging to study its outcomes," said Dr. Ram Rohatgi, first author and Mayo pediatric cardiology fellow. "Therefore, most of the previous studies had to combine data from multiple institutions, and there could be variations in how patients were evaluated and treated at each center."
Additionally, Mayo researchers found fewer symptoms than have been reported in previous studies of long QT syndrome. They believe this reflects the "changing landscape" of the disease, potentially signaling that more patients are being diagnosed earlier due to genetic testing and familial screening.
"We think this recognition of the diagnosis could be leading to earlier treatment and improved outcomes," Dr. Rohatgi said.
