Abstract: Methods, apparatuses, and systems are described for accessing a body lumen for subsequent treatment thereof. Systems include a cannula configured to penetrate a wall of a body lumen and to passively transition to a nonlinear shape within the body lumen as an elongate member is withdrawn from the distal section of the cannula. Other embodiments include a handle, a cannula removably disposed within a lumen of the handle, and a penetration member sized to advance through a lumen of the cannula, the cannula configured to passively transition to a nonlinear shape as the penetration member is withdrawn from a distal section of the cannula, and a cannula hub configured to selectively engage with a proximal end of the handle to selectively lock rotational movement of the cannula with respect to the handle.

Abstract: This invention is related to a tissue ablation system and method that treats atrial arrhythmia by ablating a circumferential region of tissue at a location where a pulmonary vein extends from an atrium. The system includes a circumferential ablation member with an ablation element and also includes a delivery assembly for delivering the ablation member to the location. The circumferential ablation member is generally adjustable between different configurations to allow both the delivery through a delivery sheath into the atrium and the ablative coupling between the ablation element and the circumferential region of tissue.

Abstract: This invention is related to a tissue ablation system and method that treats atrial arrhythmia by ablating a circumferential region of tissue at a location where a pulmonary vein extends from an atrium. The system includes a circumferential ablation member with an ablation element and also includes a delivery assembly for delivering the ablation member to the location. The circumferential ablation member is generally adjustable between different configurations to allow both the delivery through a delivery sheath into the atrium and the ablative coupling between the ablation element and the circumferential region of tissue.