Abstract 16974: Sudden Cardiac Death With Heart Failure Despite Improvement in LV Ejection Fraction: A Population-Based Study

Abstract

Introduction: Individuals with heart failure (HF) and severely reduced LVEF (≤35%) have increased risk of SCD and qualify for primary prevention ICD implantation. Guideline-directed medical therapy can improve LVEF in ICD patients but influence on SCD risk remains controversial. Hypothesis: In a subgroup of HF patients, improvements in LVEF may not eliminate risk of SCD.Aim: To identify and characterize a subgroup of HF patients who suffer SCD despite improvements in LVEF. Methods: From a large, prospective population-based study of SCD in the Northwest US (population ~1 million, 2002-2018), we identified all consecutive patients with an established diagnosis of HF and LVEF≤35%. In the sub-group of patients with at least 2 prior LVEF evaluations (earliest and latest in relation to SCD), individuals with significant improvement in LVEF over time (latest LVEF >35%) were compared to those without improvement in LVEF (latest LVEF ≤35%). Results: A total of 1622 individuals suffered SCD with a known diagnosis of HF (65% male, age 72±14) of which 434 had at least 2 LVEF evaluations over time prior to their SCD. Of these 100 (23%) had LVEF ≤35% at their earliest evaluation (mean LVEF 27±6). A subgroup of 46% (n=46) had significant improvement in LVEF between earliest vs latest evaluation (28±6 vs. 49+9, by 20±10, p<0.001) with no improvement observed in the remainder (54%, 25±6 vs. 24±7, by -1±7, p = 0.23). Comparisons of the clinical profile (demographic, coronary disease, comorbidities and medications) did not yield any identifiable differences between the subgroups with and without improvement in LVEF (Table; p>0.05 for all). Conclusions: Approximately half of individuals with SCD and a history of HF and LVEF ≤35% had significant improvements in LVEF, but this group could not be distinguished from those without improvements in LVEF by readily available clinical variables. These findings highlight the need for novel markers of SCD risk beyond the LVEF for this subset of HF patients.