Activation pattern of the coronary sinus facilitates the differentiation for ventricular outflow tract arrhythmias

Area of Science:

• Cardiology
• Electrophysiology
• Medical Imaging

Background:

• Surface ECG algorithms for outflow tract ventricular arrhythmias (OT-VAs) may lack accuracy.
• Intracardiac electrograms at anatomic landmarks offer potential for improved prediction.
• Evaluating novel criteria for localizing OT-VAs is crucial.

Purpose of the Study:

• To assess the efficacy of a new criterion using coronary sinus (CS) activation patterns for localizing OT-VAs.
• To differentiate between right ventricular outflow tract (RVOT), endocardial left ventricular outflow tract (Endo-LVOT), and epicardial left ventricular outflow tract (Epi-LVOT) origins.
• To compare the predictive value of the novel criterion with existing ECG algorithms.

Main Methods:

• Measured ventricular activation time (QRS-MA interval) from QRS onset to mitral annulus (MA) signal deflection.
• Recorded QRS-MA intervals at 3 o'clock (QRS-MA3) and 12 o'clock (QRS-MA12) on the MA.
• Compared predictive values of QRS-MA intervals with prior ECG algorithms in 68 patients.

Main Results:

• Ventricular activation sequence at MA12: Epi-LVOT, Endo-LVOT, RVOT.
• In LBBB morphology OT-VAs, QRS-MA12 was significantly earlier for LVOT origins than RVOT origins.
• A QRS-MA12 cut-off ≤10 ms predicted LVOT origin (100% sensitivity, 78% specificity); ≤-24 ms predicted epicardial LVOT origins.

Conclusions:

• The QRS-MA interval effectively differentiates the localization of OT-VAs.
• This novel method provides accurate localization of ventricular arrhythmias originating from the outflow tract.
• The QRS-MA interval shows promise for guiding therapeutic interventions for OT-VAs.