Echocardiography-Guided Risk Stratification for Long QT Syndrome

Area of Science:

• Cardiology
• Medical Imaging
• Genetics

Background:

• Identifying patients at high risk for life-threatening cardiac events in long QT syndrome (LQTS) remains challenging.
• Current risk stratification methods for LQTS require improvement.

Purpose of the Study:

• To validate the association between electromechanical window (EMW) negativity, measured by echocardiography, and symptomatic status in LQTS patients.
• To assess EMW as a predictor of cardiac events in LQTS.

Main Methods:

• Analyzed 651 LQTS patients and 50 controls.
• Calculated EMW as the difference between aortic valve closure and QT intervals.
• Used logistic regression and receiver operating characteristic curves to evaluate EMW's predictive performance.

Main Results:

• Nearly all LQTS patients exhibited negative EMW, with significantly more profound negativity in symptomatic patients compared to asymptomatic ones.
• EMW was an independent predictor of symptomatic status, outperforming the heart rate-corrected QT interval (QTc).
• Echocardiographic sonographer EMW measurements demonstrated excellent reliability.

Conclusions:

• A more profoundly negative EMW is associated with a history of LQTS-associated life-threatening cardiac events.
• EMW is a clinically validated and reliable risk factor for symptomatic status in LQTS.
• EMW is now routinely reported for LQTS patients at the study institution.