Abstract 4147532: Left Ventricular Global Longitudinal Strain is Associated with Appropriate Implantable Cardioverter Defibrillator Shocks Independent of Left Ventricular Ejection Fraction

Background: Left ventricular ejection fraction (LVEF) <35% is the principal criterion to select patients for primary prevention of sudden cardiac death (SCD) from ventricular tachyarrhythmias (VTAs) with Implantable Cardioverter Defibrillator (ICDs). Unfortunately, many SCDs occur in people with LVEF >35% and many people with LVEF <35% are actually at low risk for VTAs and SCD. Thus, identification of novel risk factors for VTAs independent of LVEF is paramount. LV Global Longitudinal Strain (LVGLS) has been associated with adverse cardiovascular events and heart failure independent of LVEF. Objective: To evaluate the association between LVGLS and appropriate ICD shocks for VTAs. Methods: 223 consecutive patients who had ICDs implanted for primary prevention of SCD at a tertiary care medical center (1/2016-12/2017) were retrospectively evaluated in 2024. Patients were excluded for inadequate transthoracic echocardiogram data (n=44) and follow-up <3 years (n=55). TTEs were retrospectively analyzed with speckle tracking to calculate LVGLS (TomTec; Unterschlessheim, Germany). Appropriate ICD shocks were physician adjudicated after review of ICD reports from the medical chart. Cox proportional hazards models and Kaplan-Meier survival analyses were used to evaluate the association between LVGLS and appropriate ICD therapies for VTAs. All statistics were completed in SPSS (Version 29.0.2.0 Armonk, NY: IBM Corp). Results: 124 patients were included (52% with ischemic cardiomyopathy (ICM), 74% male, mean age 66.3 +/- 15.3 years) with a mean (standard deviation) follow-up time 5.6 (2.3) years. Increased (less negative) LVGLS was independently associated with appropriate ICD shocks in ICM patients. The association was attenuated after adjusting for LVEF when modeled as a continuous variable per 5% increase. When modeled as a categorical variable, LVGLS > -4.5% was associated with appropriate ICD shocks independent of LVEF, age, and gender. In patients with non-ischemic cardiomyopathy (NICM), LVGLS was not associated with appropriate ICD shocks. Interestingly, LVEF was not associated with appropriate ICD shocks patients in either ICM or NICM patients. Conclusion: If our findings are validated in larger cohorts, future studies should evaluate whether analysis of LVGLS can guide therapies such as implantation of primary prevention ICDs and/or prophylactic treatment in patients with ICDs to prevent VTAs and occurrence of ICD shocks.