Systems, devices, and methods are provided for transseptal access of septa within a patient. The device can be advanced to a septum, e.g., towards a fossa ovalis. Instead of applying positive pressure to “tent” the septum, a negative pressure is applied to a lumen within a sheath, e.g., within an elongated member slidable within the sheath, via a negative pressure source such as a syringe on the proximal end of the sheath. This results in the septum pulling inward. The sheath employs a stationary needle-like central core component contained within the lumen of the sheath that punctures the septum when the same is pulled passed it by the negative pressure. The stationary needle-like central core component may be hollow and may form a portion of the elongated member or may be coupled to a distal end thereof.