Abstract: Apparatus and methods for injecting biological agents into tissue. Devices are provided having elongate shafts and distal injection heads for driving needles into tissue and injecting medical agents into the tissue through the needles. A longitudinal force directed along the shaft can be translated to a needle driving force. Some devices provide controllably variable needle penetration depth. Devices include mechanical needle drivers utilizing four link pantographs, rack and pinions, and drive yokes for driving a first needle bearing body toward a second tissue contacting body. Other devices include inflatable members for driving and retracting needles. Still other devices include magnets for biasing the needles in extended and/or retracted positions. The invention includes minimally invasive methods for epicardially injecting cardiocyte precursor cells into infarct myocardial tissue.

Abstract: A device for temporarily sealing an opening in a blood vessel is provided. The device comprises a cutting mechanism for creating an opening in a blood vessel and a seal for sealing the opening in the blood vessel. The seal is delivered through an inner lumen of a tool body coupled to the cutting mechanism. Methods for using the device to construct an anastomosis between two vessels are also provided.

Abstract: A method of performing a medical procedure, such as surgery, is provided. The system comprises a sensor to sense a biological characteristic, such as a chemical, physical or physiological characteristic of a bodily tissue or fluid. The method also comprises a nerve stimulator in communication with the sensor to inhibit beating of a heart when the sensor senses the biological characteristic at a first value; and a cardiac stimulator in communication with the sensor to stimulate beating of the heart when the sensor senses the biological characteristic at a second value.

Abstract: Methods and apparatus employed in surgery involving making precise incisions in vessels of the body, particularly cardiac blood vessels in coronary revascularization procedures conducted on the stopped or beating heart are disclosed. Such incisions are created by applying an elongated electrosurgical cutting electrode to the outer surface of the vessel wall in substantially parallel alignment with the body vessel axis, the elongated electrosurgical cutting electrode having a predetermined cutting electrode length exceeding the cutting electrode width. RF energy is applied between the electrosurgical cutting electrode and the ground electrode at an energy level and for a duration sufficient to cut an elongated slit through the vessel wall where the elongated electrosurgical cutting electrode is applied to the surface of the vessel wall.