Isolated Biatrial Cardiomyopathy Presenting as Postoperative Atrial Fibrillation: Diagnostic Value of Atrial Strain Imaging and Cardiac MRI in a Patient with Sickle Cell Trait

Background: Atrial cardiomyopathy is an emerging clinical entity characterized by structural andfunctional abnormalities of the atria, often preceding atrial fibrillation (AF). Isolated biatrial involvementwith preserved ventricular function is uncommon and frequently underrecognized, particularly inpostoperative settings where AF is often attributed to transient triggers.Case Presentation: We report a 61-year-old Caucasian female with sickle cell trait and no priorcardiovascular comorbidities, who presented with cholelithiasis and underwent laparoscopiccholecystectomy. On postoperative day 2, she developed new-onset atrial fibrillation with a fast ventricularrate. Baseline evaluation, including electrocardiogram and chest radiography, was unremarkable.Transthoracic echocardiography revealed significant biatrial enlargement with preserved left ventricularsystolic function (LVEF 63%). Speckle-tracking echocardiography demonstrated markedly reduced leftatrial strain (−5.6% and −0.3%), indicating severe atrial dysfunction. Cardiac magnetic resonance imagingconfirmed biatrial dilatation (left atrial volume index 70.25 mL/m²) and excluded infiltrative, restrictive,and structural heart diseases, with no evidence of late gadolinium enhancement.Conclusion: This case highlights isolated biatrial cardiomyopathy as a potential underlying substrate inpatients presenting with new-onset postoperative atrial fibrillation in the absence of conventional riskfactors. Advanced imaging modalities, particularly atrial strain analysis and cardiac MRI, play a criticalrole in early detection and diagnostic clarification. The possible contribution of sickle cell trait to atrialremodeling warrants further investigation.