A handle assembly for use in navigating a deformable shaft of a medical device within a body, said handle assembly having a proximal end and a distal end and said handle assembly comprising: a first guide member disposed near said proximal end, said first guide member defining first and second linear channels (64,66); a second guide member disposed distally of said first guide member and configured for rotation relative to said first guide member, said second guide member defining a circular channel in communication with said first and second linear channels; a first connector disposed within said first linear channel and movable within said first linear channel along a first axis, said first connector configured for coupling to a first steering wire, a second connector disposed within said second linear channel and movable within said second linear channel along a second axis parallel to said first axis, said second connector configured for coupling to a second steering wire, and a flexible coupling connected at a first end to said first connector and at a second end to said second connector, said flexible coupling extending from said first linear channel into said circular channel and from said circular channel into said second linear channel, said flexible coupling connected to said second guide member for rotation therewith, wherein rotation of said second guide member causes movement of said first end of said flexible coupling and said first connector in a first axial direction along said first axis and movement of said second end of said flexible coupling and said second connector in a second axial direction, opposite said first axial direction, along said second axis such that said first and second steering wires move in opposite directions, further comprising a retainer ring configured to be received within said circular channel, said retainer ring retaining said flexible coupling within said circular channel, wherein said retainer ring defines first and second diametrically opposed openings (102, 104) configured for passage of said first and second steering wires therethrough. a first guide member disposed near said proximal end, said first guide member defining first and second linear channels (64,66); a second guide member disposed distally of said first guide member and configured for rotation relative to said first guide member, said second guide member defining a circular channel in communication with said first and second linear channels; a first connector disposed within said first linear channel and movable within said first linear channel along a first axis, said first connector configured for coupling to a first steering wire, a second connector disposed within said second linear channel and movable within said second linear channel along a second axis parallel to said first axis, said second connector configured for coupling to a second steering wire, and a flexible coupling connected at a first end to said first connector and at a second end to said second connector, said flexible coupling extending from said first linear channel into said circular channel and from said circular channel into said second linear channel, said flexible coupling connected to said second guide member for rotation therewith, wherein rotation of said second guide member causes movement of said first end of said flexible coupling and said first connector in a first axial direction along said first axis and movement of said second end of said flexible coupling and said second connector in a second axial direction, opposite said first axial direction, along said second axis such that said first and second steering wires move in opposite directions, further comprising a retainer ring configured to be received within said circular channel, said retainer ring retaining said flexible coupling within said circular channel, wherein said retainer ring defines first and second diametrically opposed openings (102, 104) configured for passage of said first and second steering wires therethrough.