Lead introducer with mechanical opening valve

A transvenous lead introducer having a mechanical valve assembly disposed thereon. In a preferred embodiment, a longitudinally splittable introducer sheath is provided with a sliding valve at or near one end. The sliding valve may be spring-biased to a normally closed position. A semicircular notch may be provided in the forward end of the sliding valve, so that the sheath may be effectively sealed even when a guide wire runs through the sheath. In an alternative embodiment, the sliding valve is adapted to have its forward end inserted into a notch in the cylindrical sheath body. The mechanical valve assembly is further configured to permit use with a splittable lead introducer sheath.