Steerable electrophysiology catheters for use in mapping and/or ablation
of accessory pathways in myocardial tissue of the heart wall and methods
of use thereof are disclosed. The catheter comprises a catheter body and
handle, the catheter body having a proximal section and a distal section
and manipulators that enable the deflection of a distal segment of the
distal tip section with respect to the independently formed curvature of
a proximal segment of the distal tip section through a bending or knuckle
motion of an intermediate segment between the proximal and distal
segments. A wide angular range of deflection within a very small curve or
bend radius in the intermediate segment is obtained. At least one distal
tip electrode is preferably confined to the distal segment which can have
a straight axis extending distally from the intermediate segment. The
curvature of the proximal segment and the bending angle of the
intermediate segment are independently selectable. The axial alignment of
the distal segment with respect to the nominal axis of the proximal shaft
section of the catheter body can be varied between substantially axially
aligned (0.degree. curvature) in an abrupt knuckle bend through a range
of about -90.degree. to about +180.degree. within a bending radius of
between about 2.0 mm and 7.0 mm and preferably less than 5.0 mm. The
proximal segment curve can be independently formed in a range of about
-180.degree. through about +270.degree. with respect to the axis of the
proximal shaft section to provide an optimum angular orientation of the
distal electrode(s). The distal segment can comprise a highly flexible
elongated distal segment body and electrode(s) that conform with the
shape and curvature of the heart wall.