Abstract: Methods and apparatus of embodiments of the invention are adapted to treat tissue inside a patient's body. Aspects of the invention can be used in a wide variety of applications, but certain embodiments provide minimally invasive alternatives for treating atrial fibrillation by delivering a tissue-damaging agent to selected areas of the heart. One exemplary embodiment of the invention provides a method of treating cardiac arrhythmia. This method includes positioning a distal tissue-contacting portion of a body in surface contact with a tissue surface of cardiac tissue; detecting the surface contact between the tissue-contacting portion and the tissue surface; and thereafter, injecting a tissue-ablating agent into the cardiac tissue through the tissue-contacting portion of the body.

Abstract: An occlusive implant delivery assembly includes a rapid response decoupling or detachment mechanism that does not effect significant migration of the implant during release. The assembly includes an occlusive implant device, such as an embolic coil, a pusher or device to carry the implant to the selected location, and an expandable coupling-decoupling mechanism for releasing the implant at the selected site. The mechanical construction provides rapid release times. In addition, the releasing mechanism generally operates without exerting any significant force on the implant, thereby avoiding any significant displacement of the implant during release.