The Human Left Atrial Venous Circulation as a Vascular Route for Atrial Pharmacological Therapies. Effects of Ethanol Infusion

Objectives This study catalogued the human venous left atrium (LA) circulation system and the ablative effects of ethanol in different branches. Background Vascular routes to target the LA could have significant therapeutic potential. Beyond the vein of Marshall (VOM), the fluoroscopic LA venous anatomy has not been described. Methods Patients undergoing ethanol infusion in the VOM as adjunctive therapy to atrial fibrillation (AF) catheter ablation were included in this study. Balloon occlusion venograms of the VOM and other LA veins were obtained in 218 patients. Results Sequentially from the coronary sinus (CS) ostium, LA veins included: 1) proximal septal vein draining the inferior septum; 2) inferior LA vein in the annular inferior LA; 3) VOM; 4) LA appendage vein; and 4) anterior LA vein. Additionally, venous sinuses not connected to the CS included roof veins and posterior wall veins, which drained into the right and left atria, respectively. Venous connections between LA veins through capillaries and with pulmonary veins were abundant. Extracardiac collateral vessels were present in 38 patients (17.4%). Ethanol infusion in LA veins led to tissue ablation in their corresponding regions. Conclusions The atrial venous anatomy is amenable to selective cannulation. Consistent anatomical patterns are present. Targeting atrial tissues through atrial veins can be used for therapeutic purposes.