Rare left‐sided accessory pathway successfully ablated with atrial insertion site at the left‐side fossa ovalis

Introduction: Left‐sided accessory pathway (AP) with atrial insertion away from the annulus is an atypical variation. Conventional mapping and ablation performed along mitral annulus (MA) is usually ineffective.Methods: A 14‐year‐old girl without structural heart disease presented with recurrent episodes of sudden onset palpitations and electrocardiogram (ECG) showed a narrow QRS complex tachycardia.Results: Electrophysiology study (EPS) was done and anterograde atrioventricular reentrant tachycardia (AVRT) with AP was diagnosed. Conventional mapping and ablation performed along TA and MA was failed. 3D‐activation mapping found the retrograde atrial insertion site of AP on the left atrium fossa ovalis (FO), and AP was successfully abolished by radiofrequency ablation at that site.Conclusion: As reported, this patient is the first report of ablating a left‐sided AP with retrograde atrial insertion on the left atrium FO.