A catheter adapted for deflection in a narrow tubular region and/or sharpturn, has anelongated body, a deflection section having a support member adapted for heatactivation toassume a trained configuration, and a lead wire configured to deliver acurrent to the supportmember for heat activation. The support member is constructed of a shapedmemory alloy, forexample, nitinol, and the lead wire is adapted to directly heat the supportmember. Moreover,the catheter may include a thermally insulating layer covering at least aportion of the supportmember. The trained configuration of the support member extends in a singledimension, intwo dimensions or in three dimensions.
