Left marginal vein of heart

The left marginal vein (Lateral marginal vein of heart) is a tributary of the cardiac venous system that drains the lateral portion of the left ventricle. It runs along the lateral border of the heart, typically coursing alongside the obtuse marginal branch of the left circumflex coronary artery.

This vein is present in approximately 70-85% of individuals and exhibits variable drainage patterns. In about 80% of cases, it drains into the great cardiac vein, while in approximately 20% it drains directly into the coronary sinus. The left marginal vein typically measures 1-3 mm in diameter and may have an ostial valve in about 30% of cases.

The left marginal vein is clinically significant because it is frequently used for placement of left ventricular leads during cardiac resynchronization therapy (biventricular pacing).