Abstract 17226: Increased Risk of Heart Failure Associated With Left Atrial Remodeling Without Known Atrial Fibrillation

Background: Atrial fibrillation (AF) significantly increases risk for heart failure (HF) and independently increases mortality and adverse in-hospital outcomes in HF patients. Validated clinical risk scores (ARC2H) can predict HF in patients with AF, but are limited in application as AF is frequently clinically silent or undetected. However, AF may be preceded by significant preclinical remodeling (left atrial enlargement (LAE) or excessive atrial ectopy (EAE)). Whether LAE and EAE are associated with HF prior to AF is unclear. Method(s): We analyzed consecutive adults >65 years with outpatient echocardiography or Holter at 11 Ontario community cardiology clinics (2010-2017). Exclusions were history of AF, anticoagulation, pacemaker/ICD/ILR, and prosthetic valve. Using linked administrative databases, we assessed 5-year rates of HF (primary) and incident AF and death (secondary) associated with LAE and EAE and among subgroups (M vs. F; <75 vs. >75; CHADS-VASC 0-2 vs. 3-6). Competing risks cox proportional hazards estimated adjusted hazard of HF for severe LAE: >47mm (M);>52mm (F)) or increased APBs/hour (EAE: >30) or both LAE and EAE, adjusting for age, vascular comorbidities and left ventricular (LV) dysfunction. Results: In 28,261 adults (mean 73+/-6 years), direct age-adjusted survival was reduced for those with severe LAE and EAE. 5-year rates of HF were increased for severe (8.8%) vs. moderate (3.5%) and mild (1.4%) LAE and for those with excessive (3.8%) vs. normal (2.5%) ectopy. For both LAE and EAE, those >75 and with a CHADS score 3-6 showed marked increases in HF at 5 years compared to <75 (LAE: 10.6% vs. 7.9%; EAE: 4.3% vs. 1.9%) and CHADS score 0-2 (LAE:21.4% vs. 6.6%; EAE: 8.9% vs. 2.4%). Severe LAE increased hazard of HF 2-fold (HR=2.07; p<.0001), and incident AF over 3-fold (HR= 3.43; p<.0001) and EAE increased hazard of HF (HR=1.31; p<.0001) and incident AF (HR=1.13; p<.0001). Those with both LAE and EAE showed an over 3-fold increased hazard of HF (HR=3.28; p<.0014). Conclusions: Severe LAE and EAE without known AF are associated with increased risk of HF and AF after adjusting for LV dysfunction, particularly for those >75 and with high vascular burden. These data have implications for risk stratification, AF screening, and trials for HF prevention in individuals with left atrial remodeling.