Congenital absence of the left atrial appendage: a positive coincidence for the electrophysiologist? A case report

The congenital absence of the left atrial appendage (LAA) is an extremely rare anatomical anomaly, with only 23 cases documented in medical literature. The LAA plays a critical role in thrombus formation, particularly in patients with atrial fibrillation (AF), thus impacting stroke prevention strategies and the management of anticoagulation.

We report a 48-year-old male with a 2-year history of hypertension and prior episodes of tachycardic palpitations, who presented with AF and chest pain. During catheter ablation for AF, a transoesophageal echocardiogram revealed the absence of the LAA, initially suspected to be a thrombus. The procedure was suspended until a computed tomography confirmed the congenital absence of the LAA. The patient successfully underwent pulmonary vein isolation with radiofrequency and, after a shared decision-making process, discontinued anticoagulation. He remains asymptomatic without AF recurrence.

The congenital absence of the LAA raises important considerations for managing stroke risk in AF patients, as standard thromboembolic risk scores do not account for such anatomical variations. Despite the LAA being the most common site for thrombus formation, stroke risk in AF results from multiple factors beyond a single site of thrombus formation. Left atrial appendage occlusion is a viable alternative for stroke prevention in patients contraindicated for anticoagulation. Recent guidelines recommend individualized risk assessment using scores such as CHA₂DS₂-VA, even in atypical cases, ensuring that management strategies are tailored to each patient’s risk profile.