A catheter comprising: an elongated tubular catheter body with at least one lumen extending therethrough; a deflectable intermediate section having proximal and distal ends and at least two off-axis lumens (30, 31) extending therethrough, the proximal end of the deflectable intermediate section being attached to the distal end of the catheter body; and a distal assembly distal of the deflectable intermediate section, the distal assembly comprising: a tubular structure having a generally straight proximal region attached to the intermediate section, a generally circular main region generally transverse and distal to the proximal region; an elongated support member extending through the distal assembly, the elongated support member having shape memory; a non-conductive cover over at least the main region of the distal assembly; and at least one electrode carried on the generally circular main region of the distal assembly; at least one washer at a distal end of the deflectable intermediate section, the washer having at least two off-axis lumens (40,41), each axially aligned with a respective off-axis lumen of the deflectable intermediate section; a puller wire having two proximal portions (24A, 24B) and a mid-portion transverse to the two proximal portions, each proximal portion extending through a respective off-axis lumen of the deflectable intermediate section and a respective off-axis lumen of the washer, the mid-portion being distal of the washer and extending between the two off-axis lumens of the washer; and a control handle comprising deflection mechanism adapted to act on at least one proximal portion of the puller wire anchored in the control handle to deflect the deflectable intermediate section. an elongated tubular catheter body with at least one lumen extending therethrough; a deflectable intermediate section having proximal and distal ends and at least two off-axis lumens (30, 31) extending therethrough, the proximal end of the deflectable intermediate section being attached to the distal end of the catheter body; and a distal assembly distal of the deflectable intermediate section, the distal assembly comprising: a tubular structure having a generally straight proximal region attached to the intermediate section, a generally circular main region generally transverse and distal to the proximal region; an elongated support member extending through the distal assembly, the elongated support member having shape memory; a non-conductive cover over at least the main region of the distal assembly; and at least one electrode carried on the generally circular main region of the distal assembly; a tubular structure having a generally straight proximal region attached to the intermediate section, a generally circular main region generally transverse and distal to the proximal region; an elongated support member extending through the distal assembly, the elongated support member having shape memory; a non-conductive cover over at least the main region of the distal assembly; and at least one electrode carried on the generally circular main region of the distal assembly; at least one washer at a distal end of the deflectable intermediate section, the washer having at least two off-axis lumens (40,41), each axially aligned with a respective off-axis lumen of the deflectable intermediate section; a puller wire having two proximal portions (24A, 24B) and a mid-portion transverse to the two proximal portions, each proximal portion extending through a respective off-axis lumen of the deflectable intermediate section and a respective off-axis lumen of the washer, the mid-portion being distal of the washer and extending between the two off-axis lumens of the washer; and a control handle comprising deflection mechanism adapted to act on at least one proximal portion of the puller wire anchored in the control handle to deflect the deflectable intermediate section.