A tissue penetrating device comprising: an elongate shaft having a proximal end and a distal end and a lumen extending between the proximal end and the distal end, wherein the proximal end is positionable outside of a patient's body and the distal end is positionable within the patient's body; a first needle disposed within the lumen of the elongate shaft and extendable distally of the elongate shaft's distal end between a first configuration and a second configuration, the first needle having a proximal end and a distal end with a lumen extending between the proximal end and the distal end, wherein in the first configuration the first needle is disposed within the elongate shaft's lumen and is substantially aligned with an axis of the elongate shaft's lumen, and wherein in the second configuration the first needle is extended distally of the elongate shaft's distal end and bends away from the axis of the lumen; and a second needle disposed within the first needle's lumen, the second needle being extendable distally from the first needle's distal end when the first needle is positioned in the first configuration and being extendable distally from the first needle's distal end when the first needle is positioned in the second configuration so as to penetrate tissue of a patient, the second needle being retractable within the lumen of the first needle subsequent to penetration of the tissue so that the second needle is fully disposed within the first needle's lumen subsequent to retraction; wherein when the second needle is extended distally of the distal tip of the first needle, a distal end of the second needle is coaxially aligned with the distal tip of the first needle; characterised in that the first needle is made of a flexible shape-memory material having a preconfigured bend or curve such that the first needle bends or curves from the first configuration to the second configuration as the first needle is extended distally of the elongate shaft's distal end; and wherein the second needle comprises a proximal end and an open distal end with a lumen extending between the proximal end and the open distal end such that a guidewire is insertable through the lumen and through the open distal end of the second needle. an elongate shaft having a proximal end and a distal end and a lumen extending between the proximal end and the distal end, wherein the proximal end is positionable outside of a patient's body and the distal end is positionable within the patient's body; a first needle disposed within the lumen of the elongate shaft and extendable distally of the elongate shaft's distal end between a first configuration and a second configuration, the first needle having a proximal end and a distal end with a lumen extending between the proximal end and the distal end, wherein in the first configuration the first needle is disposed within the elongate shaft's lumen and is substantially aligned with an axis of the elongate shaft's lumen, and wherein in the second configuration the first needle is extended distally of the elongate shaft's distal end and bends away from the axis of the lumen; and a second needle disposed within the first needle's lumen, the second needle being extendable distally from the first needle's distal end when the first needle is positioned in the first configuration and being extendable distally from the first needle's distal end when the first needle is positioned in the second configuration so as to penetrate tissue of a patient, the second needle being retractable within the lumen of the first needle subsequent to penetration of the tissue so that the second needle is fully disposed within the first needle's lumen subsequent to retraction; wherein when the second needle is extended distally of the distal tip of the first needle, a distal end of the second needle is coaxially aligned with the distal tip of the first needle; characterised in that the first needle is made of a flexible shape-memory material having a preconfigured bend or curve such that the first needle bends or curves from the first configuration to the second configuration as the first needle is extended distally of the elongate shaft's distal end; and wherein the second needle comprises a proximal end and an open distal end with a lumen extending between the proximal end and the open distal end such that a guidewire is insertable through the lumen and through the open distal end of the second needle.