Bifurcated lead system for a cardiac vein

A bi-furcated medical electrical lead that is adapted to be implanted in the cardiac venous system is disclosed. The lead includes a bifurcated distal portion having first and second elongated members, or fingers. In one embodiment, the first elongated member, or thumb portion, is adapted to be positioned within the coronary sinus or great cardiac vein. The second elongated member, or finger portion, of the bifurcated distal tip, may be positioned within a branch vessel of the coronary sinus such as the posterior vein or middle cardiac vein. The thumb portion may carry at least one electrode for pacing and/or sensing, and may carry additional electrodes for multi-polar pacing applications, whereas the finger portion may carry a defibrillation electrode. Portions of the pacing/sensing electrodes may be insulated so that electrical stimulation is only delivered to myocardial tissue. According to one method of using the bifurcated lead system, the lead may be employed in conjunction with a standard right ventricular pacing and defibrillation lead to deliver bi-ventricular pacing and defibrillation therapy. Both the thumb and finger may include preformed or shapeable distal tips to aid in the positioning of these structures within the respective vessels. A stiffening member may be used to maintain the thumb in a substantially parallel position with the finger when the lead is being positioned within the vascular system, as may be accomplished with the further use of a guide catheter.