Diagnostic accuracy and clinical impact of internist-performed point-of-care ultrasound in atrial fibrillation: a multicenter study.

Atrial fibrillation (AF) is highly prevalent in internal medicine and often requires timely echocardiographic assessment. Limited availability of standard studies may delay management, particularly in acute or resource-limited settings. We conducted a multicenter, cross-sectional study across 35 Spanish hospitals, enrolling adults with new-onset or chronic AF without echocardiography in the previous 12 months, comparing internist-performed point-of-care ultrasound (POCUS) with blinded cardiologist-performed transthoracic or transesophageal echocardiography (TTE/TEE) as the reference standard. The primary outcome was diagnostic accuracy for structural abnormalities. Secondary outcomes included comparison with auscultation and the clinical impact of POCUS findings. Among 441 patients (mean age 80.4 ± 9.9 years; 51% women), POCUS showed good diagnostic accuracy for left ventricular (LV) dilation (sensitivity 83%, specificity 94%) and LV systolic dysfunction (sensitivity 81%, specificity 94%), and moderate accuracy for left atrial (LA) enlargement (sensitivity 91%, specificity 64%). Compared with auscultation, POCUS was significantly more accurate for detecting mitral and tricuspid disease. POCUS findings frequently prompted therapeutic adjustments, including anticoagulation in mitral stenosis, individualized rate-control strategies in LV dysfunction, diuretic titration in congestion, and referral for significant valvular disease. Pericardial effusion, though less common, strongly influenced management. Internist-performed POCUS demonstrated robust diagnostic performance in AF and directly informed bedside therapeutic decisions. Although it does not replace comprehensive echocardiography, particularly for detailed valvular assessment, it represents a valuable extension of the physical examination and may improve timely and equitable cardiac evaluation.