Left-sided ablation, such as for atrial fibrillation, is enabled by which approach?

• A. Left atrial access via transseptal puncture enabling left-sided ablation including pulmonary veins
• B. Direct left atrial puncture from the femoral artery
• C. Abolition of transseptal puncture
• D. Right atrial appendage ablation only

Answer: (A)

Access to the left atrium is essential for left‑sided ablation, especially when targeting the pulmonary veins. The standard, percutaneous route to reach the left atrium is through a transseptal puncture from venous access (usually via the femoral vein). Puncturing the interatrial septum allows the catheter to enter the left atrium so operators can map and deliver lesions around the pulmonary veins to achieve isolation. Direct left atrial puncture from the femoral artery would involve arterial access and isn’t the typical or safest route for this procedure. Eliminating transseptal access would make left‑sided ablation inaccessible, and attempting ablation from the right atrium alone wouldn’t achieve pulmonary vein isolation.