A New “Calculator” Analyzes 5-Year Risk for Arrhythmic Events in Long QT Syndrome


Because of COVID-19, many health and medical-related conferences and events have been moved to virtual settings. But that doesn’t mean that the learning has stopped, says Healio. During the Heart Rhythm Society Annual Scientific Sessions, Dr. Wojciech Zareba, MD, PhD, FACC, FESC, from the University of Rochester, presented a 5-year long QT syndrome risk calculator.

Long QT Syndrome

Long QT syndrome (LQTS) is a rare heart condition which can cause fast, uncontrollable, and dangerous heartbeats. These can occur sporadically, or following exercise or stress. When the heart beats too quickly and erratically, it can lead to fainting, seizures, or even death.

Genetic mutations, low potassium or magnesium levels, and certain medications raise the risk of developing the abnormalities in the heart’s electrical recharging system that cause long QT syndrome. Those with this condition require extra time for the heart to recharge between beating (a prolonged QT interval).

Many people with long QT syndrome are asymptomatic. However, episodes of fainting, sleep, or overactive heartbeat may occur during or immediately after waking up from sleep. Most people who experience this will do so before the age of 40. Learn more about long QT syndrome here.

Understanding the New Tool

According to Dr. Zareba, between 20-40% of patients between 18 and 40 will experience some form of cardiac event. However:

“when we limit the analysis to life-threatening events, this number…ranges from [6-9%].”

Alongside her team, Dr. Zareba designed a 5-year risk model to detect potential arrhythmic events. It was created using data from 1,288 patients followed over (a mean of) 9.8 years:

  • 721 patients (56%) were women.
  • 20 years old: mean age
  • 477 ms: mean QTc
  • Genetic mutations included LQT1, LQT2LQT3
  • 0.33/100 person-years: life-threatening arrhythmic event rate

Next, they validated this model using data from 1,481 Italian patients with long QT syndrome over a mean period of 7 years:

  • 770 patients (52%) were women.
  • 21 years old: mean age
  • 471 ms: mean QTc
  • 0.45/100 person-years: life-threatening arrhythmic event rate

Through this, researchers were able to discover the 5-year risk factor based on different factors like sex, age, QTc, beta-blocker use, and syncope. This will provide a risk score:

  • Less than 4%: low-risk
  • 4-6%: moderate risk
  • Over 6%: high risk

However, Dr. Zareba notes that this score would not be as effective for patients who developed long QT syndrome following infection with COVID-19 who were treated with hydroxychloroquine.

Jessica Lynn

Jessica Lynn

Jessica Lynn has an educational background in writing and marketing. She firmly believes in the power of writing in amplifying voices, and looks forward to doing so for the rare disease community.

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