A catheter for mapping and/or ablating a region of the heart, comprises acatheter body with an intermediate section that is connected to a tip assemblyby a highly flexible preshaped section. The highly flexible section presetsthe tip assembly at an off axis and/or off plane angles from the intermediatesection, to provide the following: a) The intermediate section when deflectedapproximates the generally convex region of the cavo tricuspid isthmus and thepreset angle of the flexible section is off axis in the same plane and samedirection as deflection of the intermediate section to enable the tip assemblyto contact the cavo tricuspid isthmus for ablation and/or mapping. b) Theintermediate section when deflected approximates the generally concave regionof the VA/RV/LA/LV and the preset angle in the same plane and oppositedirection of deflection enables the tip assembly to contact the walls of thecavity for ablation and/or mapping. c) The intermediate section when deflectedapproximates the generally convex region of the His area and the preset offplane angle of the flexible section enable the tip assembly to contact theBundle of His region. A high bending modulus of the flexible section enablesthe flexible section to absorb displacement force applied to the tip assembly,such as when the tip assembly encounters uneven tissue surface, withoutdisplacing the intermediate section. The flexible section prevents excessiveforce from being applied to the tip assembly, reducing the risk of any of thefollowing: a) mechanical perforation, b) steam pop, c) burying the tipassembly in the myocardium resulting in high temperatures, low energydelivery, thrombus formation and char formation.
