Abstract / Summary
Background/Objectives: In cardiovascular-kidney-metabolic (CKM) syndrome, left atrium (LA) involvement begins early: reservoir function declines before the chamber dilates, and the resulting atrial cardiomyopathy (ACM) precedes atrial fibrillation (AF), heart failure with preserved ejection fraction (HFpEF), and cardioembolic stroke. How ACM is distributed across CKM stages has not yet been characterized in routine clinical practice. ATRIO-CKM aims to characterize ACM non-invasively across the range of CKM stages in patients assessed in an internal medicine and cardiology department and to identify the parameters most strongly associated with ACM within CKM syndrome. Methods: Single-center, prospective, observational study with cross-sectional phenotyping at the index visit. We will enroll consecutive adults at their first assessment in our department (target, 200; minimum, 150). The primary objective is to estimate the stage-specific prevalence of ACM among participants in sinus rhythm without documented AF, who form the main cohort and are grouped as CKM with versus without ACM. Patients in sinus rhythm are phenotyped with 12-lead electrocardiogram (P-wave duration, Bayés interatrial block), echocardiography with speckle-tracking of the left ventricle (LV), LA (biplane reservoir, conduit, and contractile strain), and right ventricular (RV) free wall, and biomarkers including MR-proANP, Fetuin-A, FGF-23, and NT-proBNP, with cardiac magnetic resonance in an exploratory subset. Participants with AF documented at any time, including previously documented paroxysmal AF, are allocated to a separate established-AF cohort irrespective of the rhythm at the index visit. Results: We will report ACM prevalence by CKM stage with confidence intervals, the profile separating the two groups, LA volume index across three groups of increasing severity (no ACM, ACM in sinus rhythm, and established AF), and the parameters associated with ACM. Conclusions: Using only measurements already available in routine cardiology, ATRIO-CKM will describe how ACM is distributed across CKM stages and identify the parameters most strongly associated with ACM within CKM syndrome, as candidates for a classification index to be developed and validated in a larger cohort.