Key result
In Swedish LQTS patients with ICDs, the incidence of first appropriate shock was 4.3 per 100 person-years, and existing risk scores failed to reliably identify patients at low risk for shocks.
Why the study?
ICD use in LQTS is essential in high-risk patients but is sometimes used without high-risk profiles where expected benefit may be lower than ICD harm.
Can clinical risk scores accurately identify LQTS patients at low risk for appropriate ICD shocks to balance the risks of ICD harm?
Cohort (n=109)
Yes
Can clinical risk scores accurately identify LQTS patients at low risk for appropriate ICD shocks to balance the risks of ICD harm?
Current risk scores may not reliably identify LQTS patients at low risk for appropriate ICD shocks, highlighting the complexity of individualized risk stratification and the substantial risk of ICD-related harm.
Current risk scores may not identify low-risk LQTS patients for ICD shocks; leaves open need for refined stratification tools.
Objectives. The use of implantable cardioverter defibrillators (ICDs) in long QT syndrome (LQTS) patients is essential in high-risk patients. However, it is sometimes used in patients without high-risk profiles for whom the expected benefit may be lower than the risk of ICD harm. Here, we evaluated ICD benefit and harm by assessing risk according to risk scores and pre-ICD clinical characteristics. Design. We studied 109 Swedish LQTS patients drawn from the Swedish ICD and Pacemaker Registry with data collected from medical records. In addition to clinical characteristics, we used two risk scores to assess pre-ICD risk, and evaluated ICD benefit and harm. Results. Twenty percent of all patients received ≥1 appropriate shock with a first appropriate shock incidence rate of 4.3 per 100 person-years. A long QTc (≥550 ms) and double mutations were significantly associated with appropriate shock. Low risk scores among patients without pre-ICD aborted cardiac arrest were not significantly associated with low risk of first appropriate shock. The incidence rates of a first inappropriate shock and first complication were 3.0 and 7.6 per 100 person-years, respectively. Conclusion. Our findings on ICD harm emphasize the importance of careful individual pre-ICD consideration. When we applied two risk scores to patients without pre-ICD aborted cardiac arrest, we could not validate their ability to identify patients with low risk of appropriate shocks and patients who were assessed as having a low risk still received appropriate shocks. This further supports the complexity of risk stratification and the difficulty of using risk scores.
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Sundström et al. (2022) conducted a cohort in Long QT syndrome (LQTS) (n=109). Implantable cardioverter defibrillators (ICDs) was evaluated on First appropriate shock. In Swedish LQTS patients with ICDs, the incidence of first appropriate shock was 4.3 per 100 person-years, and existing risk scores failed to reliably identify patients at low risk for shocks.
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