Coronary access and delivery systems are provided. A coronary access system can include a coronary sinus guide and a first core. A lateral vein delivery system can include a lateral vein introducer and a second core. The coronary sinus guide, the lateral vein introducer, and the first and second cores may be designed or shaped to access a predetermined position within a heart of a subject. For example, the coronary sinus guide, the lateral vein introducer, and/or the first and second cores can be used in combination to access the predetermined position within the heart of the subject.
