Associations of Atrial Cardiomyopathy Markers with Incident Heart Failure

<title>Abstract</title> <p> <bold>Background:</bold> Atrial cardiomyopathy (AtCM) is increasingly recognized as an important substrate for heart failure (HF), but the comparative prognostic value of markers across different AtCM domains remains unclear. <bold>Methods:</bold> We included 30,052 UK Biobank participants without prevalent HF. AtCM markers were derived from cardiovascular magnetic resonance imaging and electrocardiography. Associations with incident HF were examined using multivariable Cox proportional hazards models and restricted cubic splines. Incremental predictive value beyond the Atherosclerosis Risk in Communities HF risk score was assessed using time-dependent receiver operating characteristic analyses. <bold>Results:</bold> Over follow-up, 288 participants developed incident HF. Left atrial markers, including left atrial maximum volume index (LAViMax), left atrial minimum volume index (LAViMin), and left atrial ejection fraction (LAEF), were independently associated with incident HF. In contrast, right atrial markers and P-wave duration were not consistently associated with HF risk. Restricted cubic spline analyses revealed a significant nonlinear association between LAEF and incident HF, with HF risk increasing at lower LAEF values. An LAEF threshold of approximately 50% identified participants at elevated HF risk. Incorporating LAEF into the ARIC HF risk model significantly improved discrimination for incident HF at both 3 and 5 years. <bold>Conclusions:</bold> Among multiple domains of AtCM, left atrial markers were independently associated with incident HF. LAEF values below approximately 50% identified individuals at increased HF risk and improved risk prediction beyond the ARIC HF risk model, supporting its potential utility for HF risk stratification. </p>