Going Off Beta Blockers an Option in Selected Low-Risk LQTS, Group Proposes

March 09, 2020

Not everyone diagnosed with long-QT syndrome (LQTS) needs to take beta blockers to cut their risk for sudden death, despite guidelines that recommend all such patients be given the drugs, say researchers based on their retrospective cohort study.

Such patients who are judged to be at exceptionally low risk from their LQTS and who want to avoid the often oppressive side effects of beta blockers can safely follow an "intentional nontherapy" strategy, the authors conclude.

The approach avoids the use of beta blockers, which the guidelines call for even in those with genetically confirmed LQTS but who are asymptomatic and whose electrocardiograms are normal.

The nontherapy also excludes implantable cardioverter defibrillators (ICDs) and denervation surgery for LQTS but maintains standard precautions, such as avoidance of QT-interval-prolonging medications.

"We are certainly overtreating this entity overall. Way too many ICDs are being put into too many long-QT patients whose risk is nominally low," Michael J. Ackerman, MD, PhD, Mayo Clinic, Rochester, Minnesota, told theheart.org | Medscape Cardiology.

"Maybe some of our long-QT patients don't need any intentional therapy," he said. "If you have somebody who's at extraordinarily low risk, and you're confident in your low-risk forecast, maybe they don't need a beta blocker."

Ackerman is senior author on the report, which was published February 24 in Heart Rhythm. The lead author is Ciorsti J. MacIntyre MD, Dalhousie University, Halifax, Canada.

"Patients themselves should not make the leap to think that they can come off beta blockers. They really have to talk to a physician who knows and is comfortable dealing with long-QT-syndrome patients," Mark S. Link, MD, told theheart.org | Medscape Cardiology.

"The thing to get across from the study, and to make sure everyone knows, is that this is a very highly selected group of long-QT patients that came off beta blockers because of perceived low-risk status," said Link, of the University of Texas Southwestern Medical Center, Dallas, who isn't associated with the current report.

Importantly, Ackerman and the report emphasize, a decision to follow the intentional nontherapy strategy calls for shared decision making after "detailed risk assessment and patient education."

But whether to take beta blockers can be a quality-of-life dilemma for many patients who have indications, Ackerman observed. Given that that the drugs are recommended universally for patients who are identified as having LQTS, "You can take a very low-risk person who never had a disease symptom and now give them a new disease called, 'I feel lousy every single day of my life.' "

In the current analysis, which Ackerman likens to a "progress report" on the strategy, 55 such patients with LQTS but no history of symptoms were intentionally not treated with beta blockers, device therapy, or surgery.

They represented 8.3% of a total of 661 patients with clinically or genetically diagnosed LQTS seen over a 17-year period at a major center. In that subgroup, there were no LQTS-triggered cardiac events or cardiac deaths over a mean follow-up of 7.5 years, the investigators reports. Even among the remaining 606 patients, there was only one death.

Among the intentionally nontreated patients, QTc intervals averaged 448 ms. On genetic testing, 85.5% of these patients tested positive for a form of LQT, and 73% had a family history of LQTS.

None in the nontreated group had symptoms; by comparison, 32% of those who took beta blockers had symptoms. For the nontreated group, resting QTc intervals averaged 448 ms, vs 469 ms for the treated group (P < .001).

Most of the nontreated patients in the analysis had started on beta blockers, "hated it, then moved to intentional nontherapy," Ackerman said.

But these days, "if we've sized up their risk forecast to be incredibly low, then we are slowly becoming supportive of not even starting beta-blocker therapy," he said.

Link pointed to limitations of the analysis. For example, there were only 55 patients in the beta-blocker nontherapy group, "and when you consider the risk of a long-QT patient having an event, it's pretty low over a 2- or 3- or 4-year time period, even over a lifetime if they are a low-risk LQTS patient," he said.

"It's a small number of patients and relatively small follow-up compared to a lifetime risk," Link said. A longer follow-up might have shown more events in the beta-blocker nontherapy group, he said, so "to say there's no risk I think would be stretching it based on the data from this study."

Ackerman said his center's LQTS program has now had over 1300 patients, compared to fewer than 700 covered by the analysis. About 10% of them were selected for intentional nontherapy after discussion with the patient and family, he said. For perspective, "I think a similar percentage of patients probably deserve aggressive ICD therapy."

The hypothetical patient he would be "most confident about moving to nontreatment," Ackerman said, might be an asymptomatic man with type-1 LQTS who is found to be genotype positive by cascade screening after age 40 and whose QTc interval is <440 ms. "That man, by everything we know about the disease, is as close to a zero-risk host that we know of."

Ackerman has consulted for Audentes Therapeutics, Biotronik, Boston Scientific, Daiichi Sankyo, Gilead Sciences, Invitae, Medtronic, MyoKardia, and St. Jude Medical and, along with his institution, has a licensing agreement with AliveCor. MacIntyre has received honoraria or speaker fees from Abbott and Medtronic. The other authors and Link have disclosed no relevant financial relationships.

Heart Rhythm. Published online February 20, 2020. Abstract

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