An assembly is provided for accessing a superior vena cava of a patient without visualization of a vasculature of the patient. A stylet has an elongated body including a core wire disposed within a tubular body, the core wire having a pre-formed shape in a first state and a straightened shape in a second state. A first portion of the core wire has a substantially straight shape in the first state. A second portion of the core wire has a first pre-formed bend in the first state. A third portion of the core wire has a substantially straight shape in the first state. A fourth portion of the core wire has a second pre-formed bend in the first state. A fifth portion of the core wire has a substantially straight shape in the first state and includes a narrow segment that increases deflection of the distal tip.