A steerable catheter device, comprising: a multilumen catheter shaft body, which catheter shaft body comprises: a proximal end length having a first durometer; a proximal intermediate length fixedly joined to a distal end of the proximal end length and having a second durometer; a distal intermediate length fixedly joined to a distal end of the proximal intermediate length and having a third durometer; and a distal terminal end length fixedly joined to a distal end of the distal intermediate length and having a fourth durometer; where the proximal end length is the longest of the lengths and has a higher durometer than at least the proximal intermediate length and the distal intermediate length; where the distal terminal end length is the shortest of the lengths and has a higher durometer than at least the proximal intermediate length and the distal intermediate length; and where a plurality of longitudinal lumens (166, 168, 176, 178, 192, 193, 197, 199) extends through at least a major length of the catheter shaft body; the device further comprising: a coil disposed around an outer circumferential surface of the catheter shaft body along at least the proximal intermediate length; and a tubular sleeve around at least the coil, the proximal intermediate length, and the distal intermediate length, where the tubular sleeve is securely fixed to and around the coil, the proximal intermediate length, and the distal intermediate length, and the tubular sleeve includes material of at least two different durometers; wherein a first sleeve durometer of a first sleeve portion overlying at least part of the proximal intermediate length is greater than a second sleeve durometer of a second sleeve portion overlying at least part of the distal intermediate length. a multilumen catheter shaft body, which catheter shaft body comprises: a proximal end length having a first durometer; a proximal intermediate length fixedly joined to a distal end of the proximal end length and having a second durometer; a distal intermediate length fixedly joined to a distal end of the proximal intermediate length and having a third durometer; and a distal terminal end length fixedly joined to a distal end of the distal intermediate length and having a fourth durometer; a proximal end length having a first durometer; a proximal intermediate length fixedly joined to a distal end of the proximal end length and having a second durometer; a distal intermediate length fixedly joined to a distal end of the proximal intermediate length and having a third durometer; and a distal terminal end length fixedly joined to a distal end of the distal intermediate length and having a fourth durometer; where the proximal end length is the longest of the lengths and has a higher durometer than at least the proximal intermediate length and the distal intermediate length; where the distal terminal end length is the shortest of the lengths and has a higher durometer than at least the proximal intermediate length and the distal intermediate length; and where a plurality of longitudinal lumens (166, 168, 176, 178, 192, 193, 197, 199) extends through at least a major length of the catheter shaft body; the device further comprising: a coil disposed around an outer circumferential surface of the catheter shaft body along at least the proximal intermediate length; and a tubular sleeve around at least the coil, the proximal intermediate length, and the distal intermediate length, where the tubular sleeve is securely fixed to and around the coil, the proximal intermediate length, and the distal intermediate length, and the tubular sleeve includes material of at least two different durometers; wherein a first sleeve durometer of a first sleeve portion overlying at least part of the proximal intermediate length is greater than a second sleeve durometer of a second sleeve portion overlying at least part of the distal intermediate length. a coil disposed around an outer circumferential surface of the catheter shaft body along at least the proximal intermediate length; and a tubular sleeve around at least the coil, the proximal intermediate length, and the distal intermediate length, where the tubular sleeve is securely fixed to and around the coil, the proximal intermediate length, and the distal intermediate length, and the tubular sleeve includes material of at least two different durometers; wherein a first sleeve durometer of a first sleeve portion overlying at least part of the proximal intermediate length is greater than a second sleeve durometer of a second sleeve portion overlying at least part of the distal intermediate length.